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(Volume 14)

S.L. Sah

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(Volume 14)
Well Logs Interpretation, and
Fundamentals of Palynology
DELHI-11 0052
"This page is Intentionally Left Blank"
Encyclopaedia of Petroleum Science and Engineering
S.L. Sah
ISBN: 978-81-7835-652-5
All rights reserved. No Part of this book may be
reproduced in any manner without written permission.
Published in 2008 in India by
Kalpaz Publications
C-30, Satyawati Nagar,
Phone : 9212729499
Lasser Type Setting by: Quick Media, Delhi
Printed at : Singhal Print Media, Delhi
"This page is Intentionally Left Blank"
Dedicated to the Geophysicists, Geologists, Engineers,
Scientists, Universities, Organisations, Teachers,
Students, and other working in different
disciplines of petroleum science
and engineering
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1. Well Logs Interpretation
2. Fundamentals of Pleontology
Appendix-A: Evolution of Species
Appendix-B: Biological Evolution
Appendix-C: National Oil Company-
ONGC (India)
Appendix-D: Important Figures and Data India
after 60 Years (1947 to 2007) 280
Appendix-E: News in Focus
India to Soon Have a Research
Base in Arctic 288
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"We usually find oil in new pla<:e with old ideas. Sometimes we fmd
oil in an old place with a new idea. But we seldom find oil in an old place
with an old idea. Several times in the past have thought that we were
running out of oil, when actually we were running out of ideas".
Professor Parke A Dickey
Fossil fuels such as coal, oil and natural ~ a s . currently supply around
85 per cent of the world's energy needs, and according to predictions
by the International Energy Agency, will continue to'do so for many years
to come. The burning offossil fuels is a major source-of excess CO
, the
gas that has most contributed to the increased concentration of
greenhouse gases in the atmosphere. There is an urgent need to reduce
the atmospheric concentrations of greenhouse gases that are likely to
produce rapid, human-induced climate change. It is possible to decrease
greenhouse gas emissions through increased energy efficiency, switching
to lower carbon-intensive fuels, enhancing natural carbon sinks
(vegetation), making greater use of renewable energy and through
geosequestration, the long-term geological storage of CO
Changes in the exploration business require a new perspective on
technology development and implementation. Due to significant advances
in sensor technologies in electromagnetic and potential field technologies
as well as in seismic technologies, there is a real opportunity to exploit
new high resolution exploration method based on richer physical
principles that go beyond just conventional seismic technology, e.g.,
newly developed electromagnetic technologies allow for hydrocarbon
charge testing remotely. Combining several of these "non-seismic"
technologies together with seismic measurements allows for reducing
sub-surface risk more than any of the individual measurements would
be able to do. These new technologies will change conventional
exploration methods, which are largely based on seismic technologies,
e.g., rock physics requires to underpin quantitative interpretation. In the
immediate future, efforts will concentrate on developing 'joint inversion"
of engineering, geologic and geophysical data. Further progress in
geosciences is likely to be based on "coordinated advances" involving
12 Encyclopaedia of Petroleum Science and Engineering
geosciences and petroleum engineering in the development of oil fields.
This definitely has a potential of mitigating technological risk. Minimizing
cost and risk through implementation of cutting edge technologies is
very important to spur the exploration activities especially deepwater
exploration. The petroleum industry has been continually equipping itself
with the new technologies, techniques and expertise needed to deal with
the challenges of the future. The pursuit is demanding and its course
uncertain, but for the petroleum companies with imagination and fleXlbility
to reach for it, the prize to be obtained will be a great reward.
Part-one of this encyclopaedia gives about the well logs
interpretation. Interpretation of well logs is very important. When the
interpreter comes to establish a tie between his seismic sections and a
borehole section, he faces the problem of making a direct correlation
between patterns of reflectors which are scaled vertically in terms of two
way reflection time and the realities of sub-surface geology as determined
by lithological logging of rock chippings and cores obtained from a
borehole. The geologist's lithological log is of prime importance in that
it provides the basis for identification of reflectors in terms of boundaries
between rocks of different type. Other geological work on the cores and
chippings aims to establish the age of stratigraphy of the geological
section and the presented results of exploration drilling normally include
a lithostratigraphic log as well as a chrono-stratigraphic scale. As far as
the seismic interpreter is concerned, the geophysical logging methods
of most value to him are gamma-ray logging, compensated formation
density logging, compensated sonic logging and well velocity surveys.
The results of these are most usefully combined to provide a synthetic
seismogram. Geophysical logs will be used to estimate formation
correlation between wells by comparison of sonic and gamma-ray logs.
The final geological analysis of a borehole is detailed in a composite
log. Where the well has penetrated and/or detected hydrocarbons,
pertinent data will be listed which may be utilized by the geophysicist in
seismic hydrocarbon indicator studies.
Part-two of this encyclopaedia gives about the fundamentals of
palynology. Palynology already has earned a prominent place in
paleobotany. The ubiquity and abundance of palynomorphs in diverse
kinds of rock provide a source of material that has enormous potential in
documenting the geological record of plants. New applications of
palynology have been recognized in geology and botany. In oil geology
particularly the phenomenal growth and expansion of palynology has
been stimulated by the successful practical application of the results of
Preface 13
research. Growth in palynological knowledge has not been accompanied
by a commensurate body of published information in the form of
comprehensive accounts of synthesis. Palynology in combining aspects
of geology and botany attracts interest from those whose background
may be incomplete in one or the other of these disciplines. Part-two
summarizes the nature, scope and application of the study of fossil pollen
and spores.
The aim of this encyclopaedia is to make interconnections among
the different disciplines of petroleum science and engineering like
interpretation of well logs and fundamentals of palynology.
At the end of this encyclopaedia five appendixes have been included.
These appendixes will give more information to readers about interesting
topics besides the petroleum science and engineering.
This encyclopaedia will help to promote understanding and
communication among users. It is suitable for geophysicists, geologists,
scientists, universities, organizations, teachers, students and other
working in different disciplines of petroleum science and engineering.
The author will be grateful for comments and criticism which might
help to improve the later edition of this encyclopaedia.
Some of the material of this encyclopaedia has been taken from the
books and the papers published in different journals. I am thankful to all
of them who have contributed to the development of this encyclopaedia.
Rishikesh (India), 2008
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When the interpreter comes to establish a tie between his seismic
sections and a borehole section he faces the problem of making a direct
correlation between patterns of reflectors which are scaled vertically in
tenns of two-way reflection time and the realities of sub-surface geology
as determined by lithological logging of rock chippings and cores
obtained from a borehole. The geologist's log is of prime
importance in that it provides the basis for identification of reflectors in
tenns of boundaries between rocks of different type. Other geological
work on the cores and chippings aim to establish the age and stratigraphy
of the geological section and the presented results of exploration drilling
normally include a lithostratigraphic log (rocks described in tenns of
lithology) as well as a chrono-stratigraphic scale (the rock units
subdivided according to age).
It is standard industry practice that at various stages during the
drilling of a well and upon reaching total depth (TD) geophysical logging
tests are made with a variety of instruments. These are lowered to the
bottom of the well, as drilled at the time oflogging, on a wire line which
is usually a multicore electrical cable on which the logging tools can be
suspended. The logging tools are then drawn upwards through the
borehole, measurements of various parameters being made either
continuously or by tests at selected horizons. The processed results of
these geophysical tools provide data which allow identification of the
interrelation between the seismic section time scale and the borehole
section depth scale and thereby directly correlation between reflector
pattern and stratigraphy. These measurements also provide data on the
physical properties of the rocks penetrated by the borehole and such
data are important to a geological understanding of the variation in
reflector pattern which can be seen in seismic sections throughout an
exploration province. As far as the seismic interpreter is concerned, the
16 Encyclopaedia of Petroleum Science and Engineering
geophysical logging methods of most value to him are gamma-ray logging,
compensated formation density logging, compensated sonic logging and
well velocity surveys. The results of these are most usefully combined
to provided a synthetic seismogram which is a process which aims to
produce from the borehole physical data a computed seismic section
display whih should be comparable with an actual seismic section
surveyed thro'\.lgh the well site.
Interpretation of well logs depends on the experience of the
interpreter because one well logs may be different from another well logs.
Well logs depend on the lithology, bore content, bore size, permeability,
etc. of the formation and mud cake thickness and well bore conditions.
Detection and evaluation of oil and gas deposits in subsurface formations
require measurements of several factors. Beside determining the top and
bottom of the pay zone data are needed on the intergranufar pore space
(porosity, ~ ) and the hydrocarbon saturation (fraction of the space which
contains oil or gas), and the way of verifying permeability of the
formation (to establish that oil and gas will be producible). All of these
can be obtained by using suitable borehole logs. The choice of the
logging suite depends on borehole conditions and on the characteristics
of the reservoir rocks.
Detailed Encyclopaedia
This encyclopaedia is arranged in alphabetical order. The detailed
encyclopaedia is given below:
Acoustic Neutron Gas Detection
The combination of an acoustic and neutron log for gas detection
is often recommended for shaly sandstones. Both measurements
are influenced by shale in the same manner and thus the gas effect
is independent of the shaliness. The only problem is that having
once detected the gas, and often the gas effect seen on the logs is small,
it is often difficult to obtain the porosity. The acoustic log does not
give good results much of the time when corrected for sP.ale content of
the formation. The neutron log has both gas and shale effects and thus
does not give us an avenue to obtain porosity. In clean formations the
density neutron combination is superior to the acoustic neutron
combination as porosity is easy to obtain. The acoustic neutron
combination is only used in some very special cases where nothing else
seems to work. Fig. I shows an acoustic-neutron overlay for a Gulf Coast
well. The acoustic log has been normalised in the water zones. The
overlay is not as good as it could be as the CNL is recorded in porosity
i:.J,UC!\.'US rute\.\ tis1
.. I ohr n.) J 5
r-' . t.
.+--.1.-.-1-- t- \1-_.
..... _.l_. --
.. ,.-+ I
L" J _,', _ .... U
, . __ .
! tmlTh
.... .....

I -- ... -...... -.
I H- .. - .- . ..:. "-

. L: ... _ _ __ _
t .
_. 0:tu!1I- :>u
- - _. ._ ..... ...:.
:L ..)_ .. 5
.. , j _ .. i-- .... :'t -----
. .. t + I
R1 . ''5"" 1 .... -. to.
l . ... 1->.. . '
. ..
I .... " I.AS
1.-.-,.... .-
.' I
\. . !
.tt I
\ __ GA'
r-f-.. f . . .- ....
. . .
. I
.. - - _ . . _. . t;AS-
. c: .. ".
..... f"-= . ''':', : . . . :: .,
--I- --

-- -
.. -
1-- -.
__ L-__ .
Fig. I. A compensated neutron and sonic log on the Louisiana Gulf Coast showing gas sands (Courtesy Schlumberger).


-J .
18 Encyclopaedia of Petroleum Science and Engineering
and the acoustic is in travel time. In some of the water zones there is an
apparent gas separation.
Advanced Gas Diction
Distinguishing between gas bearing and oil bearing reservoirs with
resistivity logs is almost impossible. Although the gas bearing zones
have lower water saturations than oil bearing zones the pore size
variations usually marks our ability to separate the two on a pure
resistivity or water saturation basis. Most gas detection today is done
with the density and neutron log. Other porosity log combinations are
sometimes used but are usually more difficult to analyze. The acoustic
log generally is not influenced by gas when the formations are well
consolidated or compacted. This includes essentially all carbonates,
cements and consolidated sandstones and unconsolidated sandstones
that are deeply buried and under normal net overburden stress. Normal
overburden pressures are those where the pore (fluid) pressure is in the
0.433 to 0.465 psilft range. Values higher than that are considered
abnormally pressured. .
Gas effects on the acoustic log show up as increases in travel time
(porosity calculated). The changes are apparently not related to the
volume of gas (gas saturation) as the influences appear on the logs to
be sharp and significant. There is little difference between 85 percent
gas saturation and 60 percent gas saturation on the travel time measured.
The gas effect appears to more influenced by the formation consolidation
or compaction than by the gas saturation. In modestly uncompacted
formations, where shale travel time is in the 100 to 125 1-1 seclft range the
porosity can be corrected using the following equation:
<p "" B <P calculated ... ( 1 )
where B is 0.7 for gas zones and 0.9 for oil zones. Equation (1) is only
approximate. The correction is of course dependent upon little or no
invasion, which is usually the case for uncompacted formations. If
invasion is deep, greater than about one foot from the side of wellbore,
there is a good chance the gas effect will not show up on the acoustic
log. When the formation is very uncompacted, with shale travel times of
over 125 1-1 sec/ft, using equation (1) is not sufficient. Travel times in gas
zones off of Nigeria was as high as 220 1-1 sec/ft. These cannot be
corrected back to a reasonable porosity. In cases where the acoustic log
cannot be corrected it is common practice to obtain the porosity in a
nearby water bearing zone and assume the gas bearing zone has the same
porosity. The acoustic log corrections for gas are not truely quantitative.
Well Logs Interpretation 19
Gas in the field of vision of the density log reduces the bulk density
and thus shows up as an apparent increase in porosity. The density log
is easier to handle than the acoustic log as the density log is controlled
by known theory. The bulk density is related to the rock and fluid by the
following equations:
Ph = <l>Pf+ (1- <1 P
... (2)
Pf =
SwPw + She Phe
... (3)
Ph =
bulk on total density
Pf =
factional density
matrix or solid material density.
water saturation
water density
hydrocarbon saturation
hydrocarbon density
S decimal fraction of pore space (saturation)
decimal fraction porosity
Since about 75 percent of the density log measurement is in the first
3 inches of formation next to the well bore the saturation values in
equation (3) could be thought of as Sxo and for Sch = 1 - Sxo With Rxo
and density the porosity can be obtained either by figures 2 and 3 or by
trial and error.
The trial and error method uses the following equations:
<I> =
S -
Pma -Pb
- Pr
... (4)
... (5)
Pf = Sxo Pmj+(1-Sx)P
... (6)
The trial and error starts with equation (4). We must guess a fluid
density between mud filtrate and the gas. The mud filtrate density is
obtained from Rmf and Chart 1 (annexure-one). From chart 1 we obtain
the mud filtrate salinity in PPM ofNaCl. The mud filtrate density is (after
Schlumberger) given as:
20 Encyclopaedia of Petroleum Science and Engineering
Pm! = 1 + 0.73 P ... (7)
Where P is the salinity in PPM divided by 1,00,000. The gas density can
be obtained from earlier Fig. 2. If you do not know the specific gravity
assume it to be 0.7. The gas density is different than the bulk density.
This is called Z fA effect. The correction for Z fA is given as:
Gas Density (gmlcc)
Fig. 2. Graph between gas density and depth.
= 1.325 Phc - 0.188 ... (8)
is called measurement density. At 20 percent porosity this Z fA
correction is just less than 1 porosity percent. This correction reduces
the calculated porosity. So without correction our porosity will be a little
high. Having gussed a fluid density for equation (4) we now calculate
our first estimate of porosity. Use this porosity in equation (5) to calculate
Sxo' Use this first Sxo estimate and equation (6) to caiculate the fluid
density. Plug this fluid density into equation (4). Recalculate equation
(5) and (6). Continue this interation until there is no significant change
in the porosity calculated from one trial and the next. We have gas
corrected the density log.
The influence of gas of the neutron log is a two fold influence. The
major influence is the reduction of hydrogen and the second is the
excavation effect (due to density reduction). The major effect/is the
Well Logs Interpretation 21
reduction of hydrogen. Reduced hydrogen look like reduced porosity on
the neutron log. The reduction is apparent neutron log porosity is a
function of how dry the gas is, the pressure and temperature of the gas,
and the depth of invasion of the mud filtrate into the formation.
Additional influences such as mud and formation water salinity are
usually very small. Excavation effect essentially relates to the fact that a
formation containing only rock and water where the water fills, for
example, 15 percent of the bulk rock volume will show up as a higher
neutron porosity than a rock with water and gas where the water again
fills 15 percent of the bulk volume and the gas fills 15 percent. The
reduction in the fraction of rock reduces the density. Both rocks have
about the same amount of water (hydrogen) but the one with the higher
actual porosity will look like it has the lowest porosity on the neutron log.
The density and neutron combination is the most popular gas
detection method. This is because the gas effects on both logs are usually
predictable and can be corrected to obtain porosity as well as determine
the presence of gas. Three different interpretation models are used
to determine porosity from the density neutron combination. Case-l
is where the mud filtrate invasion is either very shallow or very deep.
Most cases we see are the former. In this case both logs are influenced
Poroalty %
Fig. 3. Graph between density and porosity.
22 Encyclopaedia of Petroleum Science and Engineering
by the same amount of gas. See Fig. 4 when the logs detect gas the
density log apparent porosity increases and the apparent neutron log
porosity decreases. The slight separation in this figure in the water zone
is probably due to the slight shaliness of the formation. In this case the
density and neutron logs tend to mirror each other with the true porosity
between the two curves. The higher the gas saturation the larger the
separation. As the gas saturation decreases the two curves move
together until in a water sand they read the same value. The porosity for
the formation can be obtained in several ways : by empirical equation,
by density neutron crossplots, and from the density log if an Rxo log
has been obtained.
-!'0t--.. .. IVOt.," ..
I!> __
0 20

.. '-
\\ '
..... ,
. J . ,
I I ......

: .:../'2L
I '... I
. -.s __ --...-

. I
A I I ___
/ ,'" ' ..

J ". . ./. G"" eON"
!:' ! '
\..l \ ) I
' .,


... -.:-
4 }
, Am = 1.2.
\ Amf (;i)Tf
Arne=1 C

Fig. 4. Gas shows on the Density-Neutron combination (after Hung and Salisch,
13th SPWLA Trans., 1972).
Case-II results from the invasion of the mud filtrate being deep
enough into the formation to cover up the density log measurement but
not deep enough to completely cover up the neutron. This results from
the density logs 3-4 inch depth of investigation compared to the neutrons
(compensated) 6-14 inch depth of investigation. The two measurements
are being influenced by different gas saturations, the density being
usually lower than the neutron. A case-ll situation occurs in most
reservoirs with porosities under 20 percent or formation with a tendency
to invade. Case-ll density-neutron situation is recognised by the fact that
the density and neutron do not mirror each other. In a case II situation
the density log is used for porosity. Case-I and case-II gas effects on
Well Logs Interpretation 23
the density-neutron combination are easily recognised as the neutron is
always reading a lower porosity than the density log. When looking at
logs we should be aware of the scales on the density and neutron log. If
we are in a sandstone and the logs were run on a limestone porosity
scale, every time we see a clean sandstone the two curves will crossover
by about 6 porosity percent. This apparent gas crossover is even more
significant if the density log is run on density scale. The only time gas
crossover on the density and neutron log is legitimate is when the logs
are on the proper lithology scale. See Fig. 5. Many times the density and
neutron do not crossover but yet the interval produces gas. This can be
caused by either effective or non-effective shales or by heavy minerals
in the formation. If we look on a density-neutron crossplot we will see
these influences push the data point in the southeast direction while
gas pushes the data points in the north-west direction. The opposite
effects reduce or completely eliminate the "gas effect" on the density-
Case-III gas effect on the density neutron is due to shaliness, non-
effective shales or heavy minerals. In the case-III situation the neutron
Call1lla Ray
______ __________ _
o API Units 200

Apparent Sandstone Porosity %
ro W 0 -W
Fig. 5. Density/Cumpensated neutron in a cretaceous gas sand
(Courtesy Schlumberger).
24 Encyclopaedia of Petroleum Science and Engineering
porosity is larger than the density porosity. Fig. 6 shows a schematic
density-neutron plus gamma ray in a case-III situation. The upper part
of this figure shows the gamma rayon the left hand side and the neutron

f ... Density
...... .
, Gas Effect
" E
Liquid tiny
/ Cas Effect
Call1ll4 .....
Fig. 6. Schematic logs for a case III gas situation (After Hilchie, 1982).
and density in sandstone porosity for a liquid filled formation on the
right hand side. The simulated formation consists of 5 zones that are
getting progressively cleaner with depth. As the formation becomes
cleaner the density and neutron porosities move closer together until in
a clean formation the two values are the same. Gas effect is added to
zone C which shows up as lower neutron porosity and higher density
porosity. The separation between the density and neutron is reduced
due to the gas effect. The. lower pot in this figure is a method of
separating the liquid filled from the gas containing intervals. The vertical
scale is the separation of the density-neutron porosity values (cjlN- cjlD)'
The horizontal scale is the gamma ray values. In a liquid filled situation
there is a direct correlation between the increase in the gamma ray and
the separation of the density and neutron porosities as shown by the
liquid line. Gas causes a reduction in the neutron-density separation but
does not effect the gamma ray and thus gas points drop down on the
plot as shown with point C. A case-III plot is used only to identify
Well Logs Interpretation 25
potential gas bearing zones. The interpretation falls into one of the two
categories, shally zones or heavy minerals. If the minerals are heavy, just
do a conventional clean sand analysis using the density-neutron
crossplotted porosity.
Carbon-Oxygen (C/O) Logging
The carbon-oxygen log prime area of use is the determination of
water saturation in formation with fresh water, an area where conventional
logs do not work. Carbon-oxygen (C/O) logging is most applicable in
the search for oil. These are better ways to determine the existence of
gas. The idea for carbon-oxygen logging started in the 1950s with the
development of the accelerator neutron source that had high energy
neutron output and could be pulsed. In the 1970's a C/O log was
marketed. This log was obtained with stationary measurements of from 5
to 15 minutes. In the late 1970s the continuous C/O log was introduced,
by Dresser Atlas. The interpretation of the stationary and continuous
logs follow the same principles but the constants used change, probably
due to tool design changes.
Inelastic scattering is the process by which, upon being "hit" the
nucleas becomes excited. The added energy which causes the excitation
is disposed of by the giving off of one or more gamma rays. The energy
of these gamma rays is a characteristic of the nucleus from which the
emissions occur, e.g., carbon gives off a gamma ray at 4.43 MeV, oxygen
similarly gives of a gamma ray at 6.13 Me V. Other gamma rays are given
off by carbon and oxygen but these are the predominent gamma rays.
Fig. 7 shows the spectra of gamma rays from a C/O tool in a laboratory
environment where the formation is simulated by sand filled tank with
water and oil present. The peaks on the spectra occurring at 0.51 MeV
and 1.02 MeV below the primary peak are called escape peaks and are
caused by nuclear reaction in the detector. This figure is for the difference
between 100 percent oil saturation and 100 percent water saturation and
for a 10 minute stationary measurement with no borehole equivalent.
Fig. 8 is a more typical spectra for a C/O logging tool in a borehole
environment. The gamma rays counted in these energy windows are
ratioed and this is the carbon-oxygen ratio recorded. In an oil zone there
is more carbon due to the oil and less oxygen due to the absence of
water. In a water zone there is less carbon and more oxygen. Thus is a
water zone the carbon-oxygen ratio is lower than in an oil zone. For the
stationary tool, C/O ratios of around 1.6 in water zones and 1.7 or higher
for oil zones (Lock and Hoyer, 1974). See Fig. 9. This figure is for
i 1000


c 41)00
Encyclopaedia of Petroleum Science and Engineering
. - _. Oil TANK
- WAT,,. TA".
C ..... OM WINDOW OIT'GN _*oow
\ A e
! '",
\ 010['

Fig. 7. A spectra of gamma rays for inelastic scattering in a
laboratory environment.
10 10 100
120 110 180 200
Channel No.
Energy of Gamma Rays (MeV)--+
Fig. 8. A computer produced spectra from a carbon-oxygen logging device in a
borehole (After Oliver et. a!., 1981).
Well Logs Interpretation 27
1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8- 1 ',I 'i 0 2 1

Fig. 9. Stationary C/O log interpretation chart (After Lock and Hoyer, 1974).
interpretation of sandstones. Carbonates increase the carbon-oxygen
ratio due to carbon in the rock matrix. The existence of carbonate
materials in the formation must be determined so that carbonate materials
will not be mistaken for oil. The SilCa ratio can be determined either in
the inelastic scattering region or in thermal capture region by monitoring
the characteristic gamma ray energies for these reactions. The inelastic
measurements are made during the time the neutron source is creating
neutrons while the thermal capture gamma rays are monitored after the
neutron source is turned off. Lower Si/Ca ratios means more carbonate
material and less sand and thus higher expected CIO ratios for a water
bearing zone.
Fig. 10 shows the continuous CIO log of Dresser Atlas versus
porosity. The higher level of C/O is for limestones than for sandstones.
The much lower CIO ratio is for water sandstones. The C/O ratio seen
by the logging tool is effected by the liquid in the forehole, the casing,
the cement, the borehole diameter and of course statistics. Oil in the
borehole will raise the CIO ratio as the tool is not borehole compensated
(Oliver et. aI., 1981). Water lowers the C/O ratios. Even a significant
change in oil gravity will show up as a change in CIO ratio. Some of
these factors also influence the SilCa ratio. This figure shows that the
separation between water and oil bearing zones is porosity dependent.
For marginal zones with 50 percent water saturation in an oil zone the
CIO log would be very difficult to interpret reliably. In carbonate
formations the uncertainty is probably greater as the variation in C/O
ratio between dolomite and limestone should be in the order of a change
28 Encyclopaedia of Petroleum Science and Engineering

1.7r-----------------__________ -. ____
1. j


Porosity %
Fig. 10. Carbon-oxygen ratio versus porosity for various water saturation (Sw)
for continuous C/O log (After Oliver et. aI., 1981).
in cia of 0.1. In a clean sand (with a low SilCa ratio) an increase of 0.05
in cia ratio should be oil. The Cia log is more practical as an evaluation
tool for known or suspected oil bearing zones.
Density Acoustic Gas Detection
The density and acoustic log combination is only good under some
very specific conditions. Since the acoustic log only responds to gas
when the formation is not compact or consolidated so this combination
is very limited. For the acoustic and density to be a good gas detection
system the formation must be uncompacted. When this occurs the
acoustic will indicate higher porosity and the density by itself must be
used to calculate porosity. Fig. 11 shows an example of gas detection
using the acoustic and density log. In compacted formations the density
mayor may not see the gas and the acoustic will not see the gas. If
there is much invasion, the amount of gas seen by the density will be
small and no definitive indication will be available.
Well Logs Interpretation
Fig. 11. An acoustic-density combination showing gas zone of offshore
Louisiana (After Hilchie, 1982).
Dielectric Logging
In late 1970's Dielectic constant logging made its appearance
in the oil field. Two companies presently offer this service, GO (Gearhart
Industries) Wire line and Schlumberger. The major apparent use of
this log is in fresh water formations to distinguish hydrocarbons. Dielectric
constant logging is reasonably independent of variations in water salinity.
This technique does not rely upon having to known Rw. This is of
value in areas where ~ changes dramatically and is secondary and
tertiary recovery where reservoirs have been flooded with waters of
different salinity than the virgin waters and oil saturations must be
The propagation of electromagnetic waves through a material is
greatly influenced by the frequency of the waves. At lower frequencies,
from 35 to 20,000 Hz, normally used in resistivity logging, the largest
influence is conductivity. As the frequency increases the dielectric
properties of the material become more significant. Dielectric constant
logging uses frequencies in the 30 megahertz upto 1.1 gigahertz range.
The gigahertz (GHzY range is often referred to as the microwave range.
The dielectric constant is usually reference to air -as being one. A high
dielectric constant (usually associated with polar compounds like
water), means that the material is not a good insulator and weakens the
electric field. Water being polar, requires energy to orient all the dispoles
(magnet type molecules) and thus weakens the field. Dielectric constants
for common oil field materials at 70F are: air-I, water-80, oil-2
to 4, carbonates-7 to 9, sandstone-4 to 6, and shale-5 to 25. The Dielectric
30 Encyclopaedia of Petroleum Science and Engineering
Constant Logs are primarily water detecting logs. Oil and rock materials
have low dielectric constants. In fact oil and gas have lower dielectric
constants than the rock material. Dielectric constant logs measure
the dielectric constant by reduction in wave amplitude and phase
shifts in the waves. The response of the system is controlled both by
resistivity and dielectric constant. The resistivities will not agree
with the Rxo log values due to differences in invasion, depth of
investigation, etc.
The GO. Dielectric Constant Log (DCL) is a mandrel type tool with
induction type coils. It operates at 30 MHz. There are two receivers to
transmitter spacings. The log recorded shows the amplitudes at the near
and far receivers, the phase difference and the amplitude ratio. The charts
change with changes in mud properties, diameter of invasion, borehole
diameter changes and formation resistivity. Once the conditions are set
the dielectric constant can be calculated. When the formation resistivity
, I
.. '
~ s
; !
' .... I!I.
. ' ,
I ! " ;.'
l;' I

: !
, ;0
....... [ -.--
Fig. 12. An overlay of neutron porosity and dielectric constant to show
hydrocarbon zones.
is less than 10 ohm metres the DCL has troubles and when the resistivity
drops below 5 ohm metres the dielectric constant will not be calculated.
These dielectric logging systems are probably only qualitative below a
porosity of 15 percent. Qualitatively the DCL appears to be a good
overlay for the neutron log. The neutron log is looking at total water
plus oil while the DCL is looking at water. In an oil saturated zone the
neutron will round high and the DCL will record low. In water zones they
should agree. Fig. 12 shows a computer overlay of a neutron and DCL.
Well Logs Interpretation
Dual Porosity Systems
Often in carbonate fonnations there are two porosity system existing
in the same rock. There is the matrix porosity which is the intergranular
porosity. This porosity exists between the small grains. Also existing
in many carbonates is the vuggy porosity. This can be solution cavities,
moldic, secondary or big holes that supplies the permeability for the rock.
In a hydrocarbon bearing reservoir, the oil or gas is usually in the vuggy
porosity and sometimes in the intra-granular (matrix) porosity.
In carbonates the matrix porosity concept may be expanded to include
micro-porosity. This microporosity has an irreducible water saturation
in the 100 percent range. The idea is to separate the water saturation
that is associated with the very small pores and if often not a factor
in determining if the well will produce hydrocarbons or water,
from the water saturation in the large pores that is directly related to
fonnation permeability and type of production. The relationship between
these two different water saturations can be related by t!le following
Sw = VS
+ (1 - V) Swm ... (1)
S w total water saturation for the total rock
Swv water saturation in the vugs or equivalents
Swm water saturation in the matrix
V fraction of pore space represented by the vugs.
Swv is the water saturation related to what will be produced, water or oil,
and Swm is the immobile water tied up by capillary pressure. The extreme
in this case would be a fractured rock. If the matrix is 4.5 percent porosity
and the fractures are 1 percent porosity the water saturation could be
not lower than 80 percent for this conditions. This would make the
identification of a reservoir from logs very difficult. This problem can be
solved by multiple porosity systems. The major problem with this
technique is the obtaining of data to put into equation (1). Pyrite in the
rocks results in a unique problem in well log interpretation. pnder nonnal
conditions the conduction of electricity through the rocKs is via ionic
conduction, i.e., ions actually result in the passage of c u r r e n ~ With pyrite,
which is a metal, the conduction is via electrons.
32 Encyclopaedia of Petroleum Science and Engineering
The influence of pyrite on the resistivity measurement is greater
using high frequency electrical current, like the induction logs, than on
low frequency logs such as the old electrical logs. The formations with
lower Rw have a greater response to pyrite than the formations with higher
~ . The low frequency measurements such as LLd have essentially no
pyrite response at low pyrite concentrations. If the pyrite is continuous
as a thin layer the influence will be much greater and will show up as a
low resistivity thin bed. The induction log, in the case of a thin
continuous bed of pyrite will show a greater thickness than the focussed
resistivity logs. This is due to shoulder bed resistivity effects. The density
log is made almost unusable by the existence of pyrite in the rocks. Pyrite
has an apparent density of 4.99 gm/cc. This makes for a reduction in
calculated porosity of 1.4 porosity percent for every 1 percent of pyrite
in the formation. Pyrite can be identified with the litho-density log (LDT)
because it has a Pe of 17. Additionally pyrite influences the density log
because of its significant photoelectric effect. The short spacing part of
the measurement is more influenced than the longer spacing and thus
the correction can be distorted. The influence of pyrite on the neutron
logs depends upon the type of neutron log. Epithermal neutron logs
should have little to no influence on the recorded porosity. 10 percent
pyrite should show up as less than half porosity percent reduction to
the real porosity. The influence on thermal neutron logs is much larger
as iron is a significant thermal neutron absorber. At 10 percent pyrite the
porosity has been increased by 3 to 4 porosity percent. At 30 percent
pyrite the increased porosity on the neutron log is a total of 5 to 6 percent
increase in porosity the influence of pyrite on the porosity derived from
a density neutron crossplot is to create a crossplot porosity less than
the actual porosity. A straight neutron porosity (CNL) would be closer
than the crossplot porosity. The matrix travel time for pyrite is 67
microsecondlft (Clavier et. al., 1976). 10 percent pyrite would put the
porosity off 1 percent. The pulsed neutron capture logs are very sensitive
to pyrite due to the significant cross-section of iron. The matrix cross
section of pyrite is 90 cu versus 10 for sand. Dispersed pyrite has no
influence on the SP but continuou:; pyrite in a zone will cause a positive
shift on the SP. Pyrite has no influence on the gamma ray log. Gas effects
on both the density and neutron will reduce the apparent pyrite
influences as gas effects are opposite to pyrite effects.
A common philosophy is that the core porosities may be used to
calibrate the porosity log to obtain better values. This mayor may not
be true. Plug core analysis is not free from problems either. If the core is
not homogenous, the plug core data will be optimistic. Plugs, on a per
foot basis, represent a little more than 1 percent of\the volume of the
Well Logs Interpretation 33
core from which they were taken. Matching core and log porosities takes
a little fmesse. We must match the depths, compensate for missing core
and than match the porosities. A core gamma often helps. Correlating of
log and core porosities may be performed by using digitized data or trend
data that has been high graded. For the digitized correlation the log and
the core data must be digitized at the same depth interval. Usually the
log is digitized on a foot by foot basis. The core is also digitized in the
same manner. If the core is not on a foot by foot basis, it must be
converted. Once we get the core and log data digitized we can either
overlay the core data on the log, after we have depth corrected the core
data. Since the density and neutron log have a vertical resolutions of
between two and three feet a three foot filter is usually applied to the
core data to smooth it. The key to how good the filter is how good the
core data tracks the log data. A fmer digitizing interval than 1 foot would
increase the flexibility of choosing length of the filter and weights.
Different filters apply for different logs as the vertical resolution of the
density and neutron logs is not only a function of the source to detector
spacing but also the logging speed and time constant used. Filtering
data for correlations using core data and the acoustic log is much simplier.
The acoustic log vertical resolution is defined by the receiver to receiver
spacing (usually 2 feet) and the log averages linearly. Thus we usually,
for a two foot receiver to receiver spacing, apply a two foot filter that is
linear, e.g., 1 : 1. Most of the correlations between core and log porosity
can be done easier and quicker by high grading the data optically taking
into account the resolution of the tools and the statistical scatter. It is
also less expensive. The key to good core log calibrations is the original
depth correlations between the core and logs. If these are not good the
whole exercise is irrelevant.
Electromagnetic Propagation Tool (EPT) Log
The electromagnetic propagation tool which Schlumberger runs
measures the travel time of the electromagnetic wave as it passed by the
two receivers (or antennas). It operates at 1.1 GHz. The pad containing
the two receivers and transmitters is forced against the side the borehole
as shown in Fig. 13. The path through the mudcake does not influence
the measurement as long as the mudcake is less than 3/8 inch thick.
Propagation time is related to dielectric constant. Print Table 1 here shows
dielectric and equivalent propagation travel times. The two are closely
related. The non-computer output for the ETP is porosity which should
be water filled. The equation is given as :
34 Encyclopaedia of Petroleum Science and Engineering
Table 1
Detectric versus propagation times
(after Wharton et aL, 1980) (at 1.1 GHz)
Mineral I' = I'II
r 0
Sandstone 4.65
Dolomite 6.8
Limestone 7.5-9.2
Anhydrite 635
Dry Colloids* 5.76
Halite* 5.6-635
Gypsum* 4.16
Petroleum 2.0-2.4
Shale 5-25
Fresh Water at 25C 783
*Values estimated from published literature.

BACKUP t-----{
lpt nanosecim
Fig. 13. Schematic of the EPT tool (Courtesy Wharton et. al.).
Well Logs Interpretation
Fig. 14. An EPT log example with computer processed results
(After Wharton et. aI., 1980).
36 Encyclopaedia of Petroleum Science and Engineering
Tpo - tPnl
- tpm
propagation travel time obtained from the log
tpm propagation travel time obtained from solid matrix
t pwo propagation travel time obtained from the water in the pores.
Fig. 14 shows an example of the EPT combined with other logs. Zone
A is gas bearing, zone B contains light oil, while zones C, D and E are
essentially water saturated.
Empty Hole Log Interpretation
Empty holes are filled with gas at the time of logging. They have
been either air or gas drilled or have been drilled with cable tool rigs. In
empty hole log interpretation we are dealing with non-permeable
formations and formation that produce gas. The logging program is limited
to the density, neutron, gamma ray, caliper and induction resistivity logs.
The other logs do not work in this environment because the gas in the
borehole will not conduct electricity or acoustic waves effectively. Even
the neutron logs are somewhat limited in that the CNL's are either not
calibrated for gas filled holes or the tools require a neutron moderator
for them to work properly. So in empty holes the neutron logs are either
sidewall neutron logs or old conventional "uncalibrated type" neutron
logs that output in cps, inches of deflection, API units or other units. In
empty boreholes the density log must also be watched as often the
sandstone formationscave badly when being drilled with air or gas.
The three major logs are the density, neutron and resistivity. The
density log is the source of porosity. Since the formations of interest
contain both water and gas and the density log is investigating the
uncontaminated virgin zone (because of no invasion), the interpretation
requires some fmesse. The gas is a very low pressure because there is
only gas in the borehole. The gas is assumed to have a zero density.
Since gas at low pressure has a Z fA ratio significant different than the
normal water filling the pores a correction must be made. This correction
is approximately:
= 0.9353 Plog +0.1747 ... (1)
This correction is close enough to use for sandstones, limestones
and dolomites and must be used to correct the log values of density to
the "true" formation density. The neutron log responds to only the water
in the formation unless the porosity is relatively high. The existence of
significant quantities of gas in a formation will cause the neutron log to
read too low because of the change in density of the formation. This
has been called excavation effect by Schlumberger. Fig. 15 shows a plot
Well Logs Interpretation 37
of excavation effect versus water saturation. At low porosities the
influence is only around I porosity percent on the neutron log but reaches
to 6 porosity percent at porosities of 30 percent and water saturations in
the 50 percent range. It tends to increase the calculated porosity and
decreases the gas saturation, and decreases the total gas in place. Since
the neutron responds primarily to the liquid saturation it is used to
determine the liquid saturation by the following equation:

40 80
Water Saturation (Sw%)
_4L-__ J-__ -L __ __ __ -L __ ____ __ __ __
= K(2 Sw + .04
where K - 1 for 55,
1. 046 for 1s',
1.173 for dol.
Fig. 15. Excavation effect correction (Courtesy Schlumberger).
S =
... (2)
Where the liquid saturation is the ratio of neutron porosity, corrected
for excavation effect if necessary, to actual porosity. The induction
resistivity log responds only to the water filled porosity.
With the density neutron combination we can determine porosity
and liquid saturation. If no oil is present, this liquid saturation is then
the water saturation. To do this, we can either the equations or the chart
shown as Fig. 16. This figure includes the density log correction for
ZIA effects but not excavation effects on the neutron log because the
latter is small for low porosities. Using the equations we first use equation
(1) to obtain with density from the log density. Then, assuming the fluid
density is equal to and the gas density is zero, we have:
... (3)
38 Encyclopaedia of Petroleum Science and Engineering
Use Onl'l
If no
Shale IS

2 4 6

'\: ':F.
8 10 12 14 16 18 20 22 24 26 28 30
:: I::
Il 14

.:J '--.
II' r1"!
Y-- Y
I 7"
:-.... K :f... :1 'f. I
/ tl
oj :')
. I
'A. i.. '/... I- :1 '1
',,, l':-
- -
'v 0- r-" / Y-.. I
.f I P"
If rv!
Use Only
.f no
011 IS

60 Rt
3C &' 18
1\1 \.

.... u
:>- 22
kI rv 1
V b(
'f d
...;.:.. . .c. ,.-.
'-' f .. - -:.
.. ..
:\ F::
I:::: :

.: .
: .r" ,('vi""":
. 2f" :
.23 .2
'. :2

.:, , .. , .
X: r\I
So ndstone
XLlm .. ,one

k . ,:
"'\;X:'\ :,'\
2.8 2.7 2.6 2 24- 2.3 .. U II 20':
Fig. 16. Porosity and gas saturation in empty holes
(Courtesy Schlumberger).

... (4)
and Sg 1-Sw ... (5)
Using Fig. 20 we enter the chart at the bulk density and proper matrix
density, proceed vertically on the chart to the neutron porosity and read
the porosity and gas saturation directly.
With the density resistivity combination we determine porosity from
the density log and water saturation from the induction resistivity
measurement. No oil may be present in this method. Fig. 16 may again
be used only instead of the neutron porosity we input the ratio of R)R,.
Well Logs Interpretation
In equation fonn this is written as :
- Pb +..JR:JR:
~ =
... (6)
Where the bulk density has been corrected for ZIA. Water saturation is
detennined by the following equation:
R . v
S - --
l1' - R
... (7)
This method relies on conventional log interpretation concepts. If
the pore geometry is unusual the technique will be good. The density
neutron combination ignores pore geometry as it does not rely upon the
conversion of porosity to resistivity. With the combination of density,
neutron and resistivity logs we can, in an empty borehole, calculate water,
oil and gas saturation. The density neutron is used to calculate porosity
and gas saturation. Resistivity plus porosity gives us water saturation.
Water, plus oil, plus gas saturation must equal 100 percent.
Formation Water Resistivity
There are basically three ways of determining the formation water
resistivity: (1) from production or drill stem test, (2) from the SP, and (3)
from the resistivity and porosity logs (usually ir.. a water saturated zone).
Water catalogs are collections of measured values of waters obtained
from formations of interest. Usually the data is classified by formation.
The catalogs can be listings of water resistivities, well location, formation
name, etc. In fresh water mud systems (where ROlf> Rw) water catalog
values should be considered to be maximum values. The Rw (resistivity
of the saturating water) could always be less. In salt mud systems the
real Rw could be higher or lower depending upon if the problem is mud
contamination or effective shale stripping ofthe ions. The catalog values
must then be corrected to the formation temperature. SP gives good
estimates ofR
in a wide variety oflocals. Rw's from the SP are usually
considered upper limits. This is because the things that influence the
SP, like shalilless and hydrocarbon suppression reduce the SP amplitude
and result in higher calculated Rw's. Two possible things cause the SP
amplitude to be too high. The first is a pressure depleted reservoir. The
second is a non-penneable zone. In detenninations of Rw from SP make
sure we have a normal mud. A quick way to handle potassium muds is to
add -25mV to the measured SP and calculate nonnally. Determination of
Rw from porosity and resistivity logs requires a water bearing zone to be
present or if no water is present the Rw calculated is a maximum
Gas Detection in Low Porosity Formations
In low porosity formations gas detection can be a problem due to
the lack of lithology control (e.g., in dolomites and limy dolomites) or
40 Encyclopaedia of Petroleum Science and Engineering
due to lack of sufficient data to determine. The solve the problem more
data is needed. In most cases this represents the addition of the acoustic
log. In low porosity carbonates a case-I! situation is most common. Case
I! results from the invasion of the mud filtrate being deep enough into
the formation to cover up the density log measurement but not deep
enough to completely cover up the neutron. In limestones the situation
is not too bad as the lithology control is good. We can take the density
log and calculate porosity assuming a limestone matrix. In limy dolomites
and dolomites the uncertainty increases. For example, the difference
between a limestone matrix at say 2.6 gmlcc bulk density is from 6.5
percent porosity for a limestone to 14.5 percent for a dolomite. Lithology
control is absolutely essential to obtain a good interpretation. Good
lithology control can be either regional data on the formation that allows
us to have a good feel for the matrix values we must use to calculate
porosity or absolute assurance that the acoustic log is a reliable porosity
device. In many areas the acoustic log gives erroneous porosities in
carbonates. In the latter case we may have to use an R,o device as a
backup to indicate the minimum porosity for the interval. Gas detection
in complex lithology is diffi..:ult unless we know or can deduce the
lithology. All three porosity devices are needed and sometimes it is
impossible to any more than establish the range in which the porosity
will lay.
Litho-Density Log (LDT)
This log is an adaptation of the density log by Schlumberger. The
measurement system has been adapted to measure the results of low
energy gamma ray (photoelectric effects) interactions with the formations
as well as the higher energy (Compton scattering) interactions. The
standard tool has been changed slightly in that the source to detector
spacing has been reduced. Compton scattering is the physical process
used in bulk density measurements in the density log. The absorption
of gamma rays in the density log follows the equation:
N = No exp (uL) ... (1)
N counts at the detector
No counts at the source
L length from the source to detector
u absorption coefficient for Compton scattering.
Equation (I) shows that the g:mlll1a rays reaching the detector
experience an exponential reduction based on absorption of tlle gamma
rays by the formation. This relationship only takes into account Cornpton
Well Logs Interpretation
scattering. Fig. 17 shows gamma ray absorption coefficient versus gamma
ray energy. At higher energies (over 0.1 MeV) the coefficient are much
larger for Compton scattering and low for photoelectric effects. Below
o .1 MeV the photoelectric absorption coefficient become larger than the
Compton scattering coefficient. This means the gamma rays are more




01 ____ __ ____
, .
Gamma Ray Energy Mev
Fig. 17. Gamma rays mass absorption coefficients (After Hilchie, 1982).
42 Encyclopaedia of Petroleum Science and Engineering
influenced by the photoelectric process then by the Compton scattering
process at the lower energies. The reason is that Compton scattering is
predominately interaction of the gamma rays with the orbital electrons.
Photoelectric effects are the result of interaction mostly (about 80 percent)
with the K shell of the atom. Bigger atoms can absorb more energy.
Fig. 18 shows a schematic of the LDT measurement system with the higher
1""""II ___ of pholOil1Ctric ,"let
L_ U IIId Complon lan.,i",
MH. U Ip i P. Inform.lionl
R-vion of Complon
Ip information onlyl
5 is the low energy photoelactric window
H is the higher energy compton scattering window
Fig. 18. A schematic of LDT measurement system.
energy window (H) for density measurements and the lower energy
window (S) used for photoelectric measurements. High U's reduce the
counting rate in the S window and have little influence in the H window.
Pe is a function of the atomic number or size of the molecule. Te can be
measure as a function of the count rate (gamma rays detected) in a low
energy window (e.g., S). Fig. 19 shows an LDT plus CNS combination
for various rock types. Recorded are porosity from CNL, bulk density
and Pe. The Pe aids in the determination of the rock types.
Natural Gamma Ray Spectral Logs
These logs separate the normal gamma ray log into three
components. The three sources of natural radiation are : Potassium,
Thorium series and the Uranium-Radium series. Fig. 20 shows the relative
Well Logs Interpretation
GR 2.0 P!o 3

&$ 30 15 0 -15

f- ...... _.,.
r I r"'f, ..LLl. I
I r, f I
1 I
.. t
T 1 I
I :'1 iI I I
--'1';' F;;f
I 11
I TIT! , J I
I l'l I , I I I) I.' I.i" I i I I
'II 11
! lot
, 'II 'I I j I I
I ,I' I I I, I' >i I I I I
cAL I GR , ... !)PIo II I SHALE
I : ,'-!-. I: I I I I , I I I
11 "1 1.11.1 TTTT I I I I
111'1..' IJI I I.lI I I I I I I I I
TT I" m ITT!rf I, I
I: I'
1I'!l1 I I : I " 'I ' II I I'i I Il.l I t
, :J
: ! ' ' , '" I ! I I 11;1 ,,,,(OOLOM'
: I
I 1'1
I I:' ,-->: I
I Tn I I '1'_1' i
I Itt
I I I I : ,
I I i
ITl, I I ' I 11: ITill19 Ii
CAL I I , I I 1111 NIJ i I
II, ,II II',
I' t '
I tTTTL ... TI 11 -:7;...,;; -! I
! ....
I til II: 11'1 j! !,"I T

I I I ! "
1131 fN
r ' I i
, ,
I Oct.,'
I 1'1
IT TT Ii : I tt I I I f< Ii II
, I
, I CAL 'J
f j
TI I,:'
II I, i I
TT " 'i
Fig. 19. Typical LDT log responses (After HiIchie, 1982).
44 Encyclopaedia of Petroleum Science and Engineering
PO"fA 55 JUM
: II iHOltJUM SERle; s

o .!> I ,.5 2 2.5 l
'AM"" -ItAY EHI!If.G"( ( .. ltV J
Fig. 20. Gamma ray emission spectra of Radioactive minerals
(After Tittmean, 1956).
emissions versus energy for these three sources of natural gamma rays.
Potassium is the cause of much of the radioactivity we see on gamma
rays logs. A small percentage of all natural potassium is radioactive and
thus the existence of potassium in a material indicates that the material
will have some natural radioactivity. The materials that have potassium
that we encounter in sedimentary rocks are : illite, potassium feldspars,
mica and some of the smectites have potassium between the layers. The
absence of potassium in montmorillonite and other smectite clays causes
radioactivity due to cation iron exchange (CEC). Good correlations of
CEC versus gamma ray emissions have been shown. This implies that
the radioactivity comes from radioactive ions absorbed on the clay
surface due to the CEC. The clays with significant CEC must strip the
ions of the water as it migrates through the shales. The effective shales
concentrate the radioactivity due to their CEC. Marine shales are more
radioactive than non-marine shales because marine shales contain
organic type materials. These organic type materials, due to their colloidal
nature, absorb ions. Why do we have radioactive sandstones, limestones
and dolomites. Uranimn ions in the water, when exposed to a reducing
environment, precipitate out of solution. Oil and gas are reducing
Well Logs Interpretation 45
environments. If this is so, why are all formations not radioactive? It
depends upon which moves through the formation first, water or
hydrocarbons. If water migrates through the formations with no oil or
gas present the shales concentrate the radioactive ions and the other
formations maintain their low radioactivity. If oil or gas enter the formation
and then water migrates through the formation, or both happen at the
same time, the radioactive ions precipitate out and the formation is
radioactive. This also applies to fractures which are sometimes detected
due to their radioactivity. Thorium/CEC correlations are poor. Thorium is
not very soluble and is deposited with the solids. Thorium is a product
of depositional environment.
The natural gamma ray spectral logs separate the three basiC
radioactive sources using the distinct energies of each of the three
sources. Potassium gives of gamma rays with an energy of 1.46 MeV.
One of the uranium series (Bi214) gives off gamma rays with an energy
of 1.76 MeV. The thorium series is represented by thallium 208 which
gives off2.61 MeV gamma rays. See Fig. 21. The lack of distinct peaks is
T+U+K r'.
--', I \
I \
I 10 "t I
SCALE \: \T,i l'4
- '-.! \
I ,
, .
I I ,
, ,
U ---
Fig. 21. Natural gamma ray spectra (After Serra et. aI., 1980).
due to the loss of energy of the gamma rays as they pass through the
formation. The same process that the density log relies upon to measure
density. The gamma rays reaching the detector with energies around the
three energies noted for potassium, uranium and thorium are counted
and displaced as either count rates or as curves calibrated into ppm. The
overall smearing is eliminated by stripping the spectra of the background
at each energy level. This leaves only the bumps on the spectra. See
Fig. 22. A comparison of the primary run and the repeat shows significant
46 Encyclopaedia of Petroleum Science and Engineering
u,. ... ,,,,,,, ." ,... !.

'hot."", ... ,. fI
.. ... .
. _. ... - -
.. -- - - -.
- -0 _ .... _. ._
: .
. __ ....
--_... .... -- ...
::...::-:..-:::- :-:- -;:.
. ',.+:

... -

1:::- =:

:-:::...:.:.... - --
.- - -


-- - ---' F'Io-
.. -

Fig. 22. Spectral gamma ray log over Permian Carbonates in Kansas (Courtesy
Dresser Atlas).
statistical fluctuation of the curves. This is due to the low count rates or
small number of gamma rays being measured. The curves are often filtered
to make them appear smoother.
Nuclear Magnetism Logging (NML)
The NML has been around since 1959. It was developed by
Well Logs Interpretation 47
the Byron Jackson company and was put into commercial application
by PGAC (then the Pan Geo Atlas Corp.). Now Schlumberger has
developed the NML. The logging tool consists of a coil through which
a large direct current (DC) is passed. The magnetic field caused by this
action orients the protons (the hydrogen nucleus which is the
only common reservoir rock or fluid material to respond). When the
magnetic field is released the protons are accordingly released. The
protons, which are always spinning like a top, start to fall out the pattern
caused by the magnetic field and return to the original orientation which
is controlled by the earth's magnetic field. The process results in the
proton precessing. This precession releases some of the energy that was
put into orienting the protons. This released energy is measured by the
coil as a variation in the magnetic field. The energy detected by this
system is related to the number of protons that are free to be oriented
and relaxed (allowed to return to the original alignment in the earths
magnetic field). This energy is very small. The proton that are free and
thus measured are those associated wit the bulk water and oil in the
formation. Protons that are absorbed or chemically bound in materials
are not free. These include solid hydrocarbons, tar, fluids in shales, water
in gypsum, etc. See Fig. 23. The free fluid index (FFI) or the equivalent
free fluid filled porosity (4).1) is obtained by extrapolating back from
the received signal to the beginning of the time of precession.
Fig. 23. A pictorial representation of fluid signals in a NML
(After Coolidge and Gamson, 1960).
48 Encyclopaedia of Petroleum Science and Engineering
The exponential rate of decay is referred to as T
This is recorded
alongwith 4>1 4>1 is recorded in a continuous mode. A comparison of
porosity from the density log or crossplot porosity with 4>1 will indicate
the liquid bound to the formation. The mud is treated with a magnetite
slurry before logging with an NML. This causes the mud signal to decay
very quickly and thus not influence the measurement. Fig. 24 shows an
example of 4>1 from an NML and a set of conventional openhole logs.
The 4>1 is always less than the porosities indicated by the other logs.
These logs are from the Texas Gulf Coast and thus are in essentially
sandstone and shale sequences (Herrick et. at., 1979). Since the 4>/is
related to the surface area of the rock it is expected that the determination
of permeability could be better. Gas will show up as a lower 4>1 due to the
lack of hydrogen.
.2 LL8
- - - ~ " ,
Fig. 24. An example of dual induction, porosity and NML logs
(After Herrick et. aI., 1978).
An additional measurement that can be made with the NML is T

Although TI and ckf can be measured more accurately fi-om a stationary
mode they are also both obtainable (with reduced accuracy) from the
continuous mode. T2 is the bulk relaxation time of the liquid in the pore
Well Logs Interpretation 49
spaces. T, is the relaxation time of the complete system, i.e., bulk liquid,
adsorbed liquids and anything else. This can be measured as the total
energy needed to polarize the material or the total energy given off during
relation. Bulk relaxation times are thus longer than T, because of the short
relaxation times of protons in solids or bound to surfaces. T, is also
influenced by the coexistence of oil and mud filtrate when the mud filtrate
has a different T,. See Fig. 25. The hydrocarbon looks like it influences
- - J,..1.
...... : .. ,- : . "t+:----= ,
.. ..... -Fqrmalion: . ',-, -.'
.. +- .. .... of Tl"2.000 MS-...... +' ffif-':---J
, ' I " ',I : I
, j
: : 1.. -
Time (millisecs) ms
Time ms
Fig. 25. Tl measurements: (a) for an oil zone, and (b) for a water zone
(After Collidge, 1962)
the T, by increasing the surface area. Fig. 26 shows the influence of water
saturation versus hydrocarbon (decane) saturation on T, versus mercury
injection pressure (which relates to pore size). The higher the mercury
injection (capillary) pressure the smaller the pore size. The porous media
is porcelain samples. Residual oil saturation has also be determined using
the NML. Residual oil saturation is needed for enhanced oil recovery
50 Encyclopaedia of Petroleum Science and Engineering
Fig. 26. Relationship between Tl and Capillary pressure.
methods. The mud is treated so that it has a very short relaxation time.
Thus the only signal comes from the oil and the FFI reflects only the
residual oil and not the mud filtrate. For this to work invasion must be
efficient and greater than about 6 inches.
Porosity and Lithology Determination
The conventinal density-neutron and acoustic-neutron crossplots
assume that the rock is composed of two minerals. In mathematical terms
the solution is one of three equations and three unknowns. One of these
unknowns is porosity. These conventional crossplots can be used
singularly or in combination. Fig. 27. This crossplots for the density-
CNL for the appropriate fluid density assume a two minerals composition
of the rock. In most cases the porosity obtained is good. We discuss
only relatively cleans rocks filled with liquid. Since both the neutron and
density log respond to density, if we adopt the theory that as the points
on this chart move to the lower right hand corner (they move in a
southeast direction) the matrix rocks have increased density. Then the
lines labeled sandstone, limestone and dolomite are not lithology lines
but lines of rocks with matrix densities of2.65, 2.71 and 2.87. A sandstone
with a heavy quartz matrix, and there are a significant number, will plot
towards or on the limestone line. A sandstone with anhydrite or dolomite
cement will also leave the sandstone line and more towards the dolomite
line depending upon the fraction of cementing material present. For
example, a sandstone with significant amounts of ironstone will plot below
the limestone line. The porosity read from the chart will be about right
but the lithology cannot be read off the labeled lines.
Well Logs Interpretation

.. --.
I : ... , ::=-="IHZ T
... _ .: - -P'- - - +:... _ .
fY" . . I/" " - - -----, ---'"
. '. ::;t -: ':--=----..)'. 1-20
co 24
. l'l /' ':1".' . .. . ... Y', .... ::i

. V" "'- .. --l;L .. -- ..

. 0':' :.:.:
. . ... -. Y.::.. ... . - .. +w: --' 1---- a:

. w - ... :/. . . "-'bl'--' - .... --. 1---.
: . /. v'_:: . __ . + ___ 10
/: : : . v. : .: '" : :.: : ---.- -.-
........ ". ". ',c.y' "'... .. >-
ce 27 .. if . - - '. .... - PI -1.0 l-
I--. ----- H
: .... :
2.8 .. : '
-. --.--/------/------
2.9 ',:-;-' 'i"r<: 1 #' ... ' :::-:: __ .. .
o w
Fig. 27. Density/CNL crossplot (Courtesy Schlumberger).
Fig. 28 is a acoustic-CNL crossplot. Although the reservoir rock lines
still fall in the same density order they did on the density-neutron chart,
anhydrite and saIt are not properly located for the density theory.
Increases in apparent matrix travel time do not always represent increases
in density. To use acoustic-neutron crossplots takes a little more lithology
information to get good porosity numbers. For example, the 10 percent
porosity lines are not nicely lined up as we go from sandstone to
limestone to dolomite. Thus for a travel time of 63 microsecondlft and a
CNL apparent limestone porosity of 11 percent there are two possible
porosities. If the rock is really a limestone the porosity is 11 percent, if
the rock is a cherty dolomite the porosity is about 9.5 percent.
Fig. 28. Sonic/Compensated neutron (CNL) crossplot
(Courtesy Schlumberger).
There are three different schemes for using the three porosity logs
in combination but from a hand calculation approach only one gives us
porosity. The other two give us a lithology indication that we can use to
help solve the problem. Looking at the problem of three porosity logs
and the need to solve for porosity initially leads one to think of solving
Well Logs Interpretation 53
the four equations and four unknowns with simultaneous linear
equations. We must know what rock types are there before we can solve
the equations. This is not always practical. To determine the porosity
with three porosity logs requires the use ofa chart like Fig. 29 (a' mineral
Fig. 29. Determination of P
a from density and CNL logs for fresh mud
(Courtesy Schlumberger).
identification or MID plots). Entering this chart with density (or apparent
limestone density porosity) and the apparent CNL limestone porosity
we obtain the apparent matrix density (P
a). From this we inter Fig. 30
a ~ d for the combination of minerals we think are present we obtain an
apparent matrix travel time (t
a). With this apparent matrix travel time
we, go to a conventional travel time versus porosity chart like Fig. 31
and. calculate porosity. The following is a check to determine if our matrix
estimation was correct.
54 Encyclopaedia of Petroleum Science and Engineering
., ,
Fig. 30. Matrix determination plot (After Hilchie, 1982).
1. <PA = <PDN' the porosity is correct and the lithology is
the expected san'dstone-limestone, limestone-dolomite or
2. <PA < <PDN' we may have secondary porosity and the acoustic log
is ignoring some of the secondary porosity. Please check the
calibration of the acoustic log.
3. <P A > <P DN' the lithology we chose was wrong. Try other
combination of minerals. This will give us a different apparent
Well Logs Interpretation 55

-":! r.,

:YJ SJ : 's::::.
g ...:!.s ,. "'t
-!..:.t .o)


; 8
I-f>- ... t
I-!' .....
'=FIg, ...
... "" ....
=; g g
_ ,. 0

= ...
1,,'tIo.n VI .:...
.. ..
. .


...... ==
I .:::::
:0 -'I":::::
o 'i' 1 ___

.. n -


4-' or

"" 0






,. ::: ...
'is 0
0:> ....

o o
Fig. 31. To find porosity from the acoustic log (After Hi\Chie, 1982).
matrix travel tim\!. Continue this changing oflinear combinations
until we obtain a porosity match.
Porosity and lithology determination from MID ploto, we use
to density, neutron and acoustic logs to obtain both apparent matrix
density (Pma a) and apparent matrix travel time (t
a) from earlier figures
and from Figs. 32, 33 and 34. Having determined the apparent matrix
density and travel time we can enter earlier Fig. 30 and obtain some idea
of the matrix materials. In this case the formation must be gas free and
clean for the determination to be reasonable. The triangles constructed
56 Encyclopaedia of Petroleum Science and Engineering
DUERMtWA liON OF (.t ".,)", FROM SONIC ANr; CN.l t tOGS
Fig. 32. To detennine (t
.) a from sonic and CNL logs
(Courtesy Schlumberger).
Well Logs Interpretation
OETERMINATIC)N Of' (P ..... lr.

Fig, 33, To determine (Pm) a from FDC and SNP logs for fresh mud
(Courtesy Schlumberger).
58 Encyclopaedia of Petroleum Science and Engineering
Fig. 34. To detennine (1m) a from sonic and SNP logs (Courtesy Schlumberger).
Well Logs Interpretation
Fig. 35. MID solutions for various rock combinations (After Hilchie, 1982).
60 Encyclopaedia of Petroleum Science and Engineering
% dol- --
VIs + V
+ Vsd = 100%
Fig. 36. Matrix density for tri-matrix : sandstone, limestone, and dolomite.
v + v + v = 100%
dol anh sd
Fig. 37. Matrix density for tri-matrix : sandstone, dolomite, and anhydrite.
Well Logs Interpretation 61
Fig. 38. Matrix density for tri-matrix : limestone, dolomitl, and anhydrite.
using clean matrix points indicate the possible solutions. Using three
porosity logs we are only allowed to try and solve for three rock types.
That is a point represented by : P
a = 2.72 gmlcc and t
a = 50
microsec!ft falls in two triangles. It could be a combination of dolomite,
limestone and quartz or it could be limestone, anhydrite and quartz. Both
of these triangles, or mathematical solutions can be solved with no
problems. Of course only one is probably correct for the given formation.
Or if the rock actually contains four matrix components none of the
solution may be correct. Fig. 35 shows a break down of the triangles for
limestone, dolomite and anhydrite. We can go into one triangle with the
apparent matrix density and travel time and obtain the proportions of
limestone and dolomite. Anhydrite is obtained by subtracting the percent
of limestone and dolomite from 100 percent. These mineral fractions
should only be considered, at best, approximate. Using these mineral
fraction we can then enter Fig. 36 and obtain an apparent matrix density
for the combination of the three minerals. The apparent matrix density
can then be used with the conventional density porosity chart to obtain
a porosity. Figs. 37 and 38 are matrix density charts for mineral
combinations of sandstone, limestone and dolomite and dolomite,
62 Encyclopaedia of Petroleum Science and Engineering
sandstone and anhydrite, respectively. Fig. 39 is a conventional density
porosity chart.
In complex lithologies even with the best data we can only approximate
porosity. Secondly, using two porosity logs in complex lithologies can
result in porosities that are significantly different than the true porosities.
:..,. III
+: j:.

'.: f

. '"
i ,


ffl .

:::;:;::;:::;: 1 II
' .
, I I
I t'
.. ,
tl .

- 1'"1,.::
::; <;
, . .....
, II

'1 !...:,:

f;': :
L, .",
.. !!i
.. ,
1!1 .+
.. 4 1




" c::
" c::




Well Logs Interpretation 63
Pulsed Neutron Capture Logs
Pulsed Neutron Capture (PNC) logs such as the TDT and Neutron
Lifetime have been commercially available since about 1962. The key to
the measurement is a neutron source that can be turned off and on. These
electronically controlled sources produce fast (14 MeV) neutrons. The
measurement is a pulsed system. The neutron source is turned on for
some discrete time (typically from 20 to 200 micro-seconds) and then shut
off. The neutrons produced scatter off things like hydrogen atoms and
slow down by elastic type scattering. Once they reach a stable energy
(or velocity) they are called thermal neutrons. At this stage they are like
gas molecules in that they have a velocity that is controlled by the
temperature. At this stage in their life they are very susceptible to being
captured by some atoms and not others. This property of materials that
is a measure of the ability of atoms to capture thermal neutrons is the
thermal neutron capture cross section. Normalizing the cross sections to
where NaCl is one, Print Table 2, shows the relative capture cross section
for various common materials 3 found in sedimentary rocks. Print Table
3, shows a comparison of various capture cross sections for sedimentary
rocks and associated fluids. Thermal neutrons are more readily absorbed
by chlorine than the other common materials. Hydrogen does influence
the cross section. Essentially capture cross section is dependent upon
primarily water salinity and hydrogen content. The capture cross section
of a reservoir rock filled with salty water, oil and other materials is given
by the equation as :
Table 2
Thermal neutron capture equivalents to NaCI
Factor to Obtain EqUivalent NaCI ppm
, 64 Encyclopaedia of Petroleum Science and Engineering
Table 3
Capture cross section of sedimentary rocks and
associated fluids
Material Capture Cross Section
Water 22 (10-
or c.u.)
Water (100 kppm NaCI) 59
Water (200 kppm NaCl) 100
Crude oil (dead) 22
Methane (1500 psi 100F) 4
Limestone (zero porosity) 8-10
Sandstone (zero porosity) 8-13
Dolomite (zero porosity) 8-12
L.t formation true or actual cross section
4> fluid filled porosity
S"o fraction of pore space filled with water
(water saturation)
Cross section of formation water
Cross section of reservoir rock at zero
L."c Cross section of hydrocarbons.
Equation (1) indicates that at zero porosity reservoir rocks will have
a cross section of around 10 cu. For 1 00,000 ppm NaCl water filling the
pores as the porosity reaches 10 percent the cross section will be 15 cu
while for 20 percent porosity the cross section will be 20 cu and for a 30
percent porosity it will be 25 cu. Hydrocarbons present will reduce these
capture cross sections.
The measurement of capture cross section requires that the rate of
thermal neutron absorption be measured. This is called Lifetime or
Well Logs Interpretation
Thennal Decay Time. These are related to cross section as shown by
the following equation:
3150 4550
... (2)
L = half life of the neutron in microseconds
T = thermal decay time or mean lifetime of
neutrons in microseconds
~ = cross section in cu or (10-
The larger the cross section the shorter the life-time or decay time
of the neutron population. The pulsing of the neutron sources at about
1000 times per second produces a cloud of neutrons that slow down
and then are captured with little to no hang over between pulses. The
logging tool has a gamma ray detector located on the tool mandrel about
15 inches above the 40 source. Fig. 40 shows the counting rate at a
detector versus time for a laboratory logging tool in a simulated borehole
environment. The neutrons in the borehole environment die away
quicker and their presence is not noticable after about 400 microseconds.
The neutrons in the formation have a longer life and their
presence is noted as an exponential decay after the borehole signal has
gone. The capture cross section is related to the slope of the fonnation
Dresser Atlas uses two time gated windows which measure the
neutrons arriving 400-600 and 700-900 microseconds after the source is
shut off and determine the equivalent of the slope of the line in earlier
Fig. 40. Schlumberger either uses three controlled floating windows that
vary in width and time location or a series of fixed windows. These are
the TDT-K and TDT-M respectively. Most PNC logs are obtained in
cased holes where sufficient tiille has elapsed for the invaded zone to
disappear. This time can take from days to months depending upon the
reservoir conditions. With a good cement job and a water zone below
a gas zone the capillary forces will pull the invading fluids into the
water zone within days. If no water zone is present it will probably take
weeks to disperse the invasion fluids into the reservoir. The vertical
resolution of the PNC measurement is in the order of 2 to 3 feet.
The measurement is subject to statistical fluctuations which require
66 Encyclopaedia of Petroleum Science and Engineering
. 'the rmal Decay. Tin.e
", 256
TIME t}Juc)
Fig. 40. Pulsed neutron capture determination of thermal neutron decay
time in a simulated borehole (After Hilchie, 1982).
low logging speeds. The true test of statistics on a log is how well
the multiple passes of the log repeat. Fig. 41 shows the limitations of the
system with regards to porosity and water salinity. The quantitative range
of use for gas reservoirs is wider than that for oil reservoirs. This is due
to the very low cross section for gas (about 4 eu on the average)
relative to the higher value for oil (around 22 eu). The wider the
separation between the water saturation lines the more quantitative the
Well Logs Interpretation 67
interpretation should be (Hilchie, 1982). The best cross section we can
measure is probably one cu and the best porosity resolution is one
porosity percent.
Equation (1) is used for all interpretations of clean sands and
carbonates. The known parameters are obtained from a series of charts
like Figs. 42, 43 and 44. We must know the salinity of the water to perform
a calculation to determine water saturation. The water salinity can be
I > .. : I : .... : r
.... _ ..... I J . ....... .. l -- I
30 t -i t ive . .

.:. 20 40 60 80 100 120

100 120
Fig. 41. Pulsed neutron log applicability (After HiIchie, 1982).
68 Encyclopaedia of Petroleum Science and Engineering
determined from the usual water catalogs, Rwa and SP analyses. The cross
section of methane (or gas) is a function of both temperature and pressure
as these control the hydrogen content of the gas. The pressure of the
reservoiHs-OOtained by dividing depth by 2 in psi. Usually oil is assumed
to have a cross section of 22 cu. The PNC logs are not too sensitive to
the type of the rock. An analysis of Fig. 45 shows that the interval 6592-
6620 (all NLL depths) is hydrocarbons and actually produce oil. There is
an oil-water contact at 6596 (NLL). The sand at 6553-6568 (IES) was the
original completion and shows water saturations on the NLL of 55 to 80
percent. The thin sands centre around (NLL) 6542, 6550 and 6578 still
appear to be productive. Water saturations from PNC logs are not subject
to pore geometry problems as are resistivity logs.
Pulsed Neutron Capture Logs (Interpretation)
The interpretation on PNC logs gives an independent determination
of water saturation where porosity is known. Although the PNC logs are
not as accurate at determining water saturation due to the often small
differences between water, oil and gas on the cross section curve they
can be used where resistivity logs may not be used. The PNC logs can
be used in cased holes is of great benefit to determine the condition of
the reservoir at periods of time long after the casing has been set. The
PNC logs distinguish between oil and gas, which resistivity logs do not,
and that the PNC are not influenced by pore geometry where resistivity
logs can be. Resistivity logs can be interpreted at low porosities where
PNC logs are not quantitatively usable at low porosities and low salinity
waters. Interpretation ofPNC logs fall into two categories: (1) evaluation
of hydrocarbon content of reservoirs at some fixed time after the well
has been completed (this can be either exploration or exploitation), and
(2) monitoring of the changes in hydrocarbon content with time.
Qualitative uses of the PNC logs such as geological mapping are of
course obvious as the PNC logs look much like resistivity logs and are
easy to correlate with resistivity logs.
Calculation of water saturation falls into two categories. One is the
direct use of cross section, porosity, matrix cross section and water cross
section into following equation :
Well Logs Interpretation
l ~ l O '
22:J, 000
- no
180.000 .
. 90
'!'If:.OOO -
" 80
. ~ .
~ ,
So -
1'20,000 '1
.80,000 .
Fig. 42. Water cross sections.
Encyclopaedia of Petroleum Science and Engineering
, 20000

10,...-------------.-.,...... ...........
i 6 - ----- 0 -. ----*l-+:H
10 12
Fig. 43. Gas cross sections.

.00 --- . -- + - J
lOO ___ o ____ __ __ __ o --
zoo .... !
.:....--;_. -:- . _0 __ - _ . ....L_-:':"" .. _-+_! _.
Q U a 20
_t ... c ... ,
2Z 2. 21 2.
Fig. 44'. Oil cross sections (After Hilchie, 1982).
Well Logs Interpretation

_ _ J
s: . '
(:: ..
9 . _____ . ("'.-!.I _________ }QQQQ
Fig. 45, PNC (Dresser Atlas Neutron lifetime) log and induction electrical log on
Offshore Taxas Well (After Hilchie, 1982).
= , .. (1)
Second method is from nomographs. Shaly sandstone interpretation
using PNC logs is not as good as for resistivity logs because shales
generally have relatively high cross sections. In most cases when we
are looking for bypassed production with the PNC logs we do not have
god control of porosity. At these times the dual spaced PNC logs are
helped. The Schlumberger TDT-K and TDT-M allow the calculation of
water saturation and porosity.
The most valuable contribution made by the PNC logs is the ability
to monitor the reservoir after casing has been set and the well produced.
The overlaying of the cross section curves as changes in water saturation
occur due to the rise of the oil (or gas) water contact or the over running
of water provide a quick and easy tool to diagnosis what is happening.
72 Encyclopaedia of Petroleum Science and Engineering
Fig. 46 shows a case in which the oil water contact is rising. The apparent
water oil contact in run #2 was too high due to water coning. Run #3
shows the actual water contact after a few months of shut in. The
separation of the curves is a direct indication of the change in water
TABLE - - ,---:
ACTl:AL ....

Fig. 46. A PNC showing a rising oil water contact (Courtesy Schlumberger).
Well Logs Interpretation 73
saturation between run #1 and run #2 of course excluding statistics. This
figure shows significant statistical variations. This could have been
eliminated by multiple runs and averaging of the multiple runs. In an
equation form the difference in cross section (L\L) between run #1 and
run #2 is:
L\ S =
~ ( L W - Lh)
... (2)
Equation (2) only needs porosity and the water and hydrocarbon
cross sections to make the determination of the change in water saturation
quantitative. If there is no change in water saturation the cross section
will not change unless there is a significant increase in gas saturation
which could result in the decrease of the cross section measured with
the log. The determination of residual oil after the zone has been watered
out is a popular application of PNC logs. In this application the zone is
logged and the water with significantly different salinity and cross section
is injected into the formation to displace tlle original water and the interval
relogged. The water saturation is then:
~ ( L w l - L
... (3)
Usually the water in the formation is salty and fresh water is injected.
This often plugs the formation and causes incomplete flushing of the
formation water due to preferential flow channels being set up in cleaner
stringers or fracturing of the formation.
Special caution should be used when working with PNC's in
carbonates. Acid treatments with HCl result in anomalous behaviour due
to the chlorine left in the formation after the treatment. The interaction
ofHCl acid plus limestone or dolomite results in calcium carbonate. This
calcium carbonate stays in the formation and results in a larger cross
section on the PNC's. Fig. 47 shows an example ofPNC logs before and
after an acidization job (AI-Saif, 1979). This particular well was
reported to have produced 1,000,000 bbls of oil between the acid job
and the after PNC. The only way to remove this chlorine effect was to
back flush the core with water.
Pulsed Neutron Capture (Tool and Log Differences)
Now the Dresser Atlas Neutron Lifetime Logs (NLL) is 1-11116 inch
in diameter tools. The measurements could be made without pulling the
74 Encyclopaedia of Petroleum Science and Engineering
well tubing. The smaller diameter tools are of course bothered more by
statistics due to lower neutron source output and small diameter detectors.
Schlumberger originally came out with a 3-5/8 inch diameter tool and then
added a 1-11116 inch tool later. The Dresser Atlas NLL log originally only
displayed the counting rates of the two time displaced windows. Latter
the two windows were used to calculate cross section and the log looked
like Fig. 48. Gate 1 was taken from 400 to 600 microseconds after the
neutron burst and Gate 2 from 700 to 900 microseconds after the burst.
The cross section was calculated from this data. The dotted curve in track
1 on the left hand side is the monitor curve which indicates the level of
neutron output from the source. The casing collar locator (CCL) is the
curve immediately to the left of the depth column. A gamma ray log was
( ; Oft." 1M 1II011(
~ .Al!O "IU ACID I0Il1( 'OIlOSIT,
I ____ _ .. __
~ - I - - f - - - + - - I , ~ - -
Fig. 47. PNC logs before and after acidization (After AI-Said et. aI., 1979).
Well Logs Interpretation
Gamma Ray
1;0 API U!\,ITS
I ;>
. 1 .
; .
1 .

---",,':.. ..
; .
Fig. 48. A Dresser Atlas Neutron lifetime log from offshore Louisiana (Courtesy
Dresser Atlas).
tiel 00
'"AWA_ DEC A .. T, .. IT)
"(UTlla" caPTu_C CIltOSS II
c".''''_' """'''s I,
Fig. 49. Thermal decay time log (Courtesy Schlemberger).
76 Encyclopaedia of Petroleum Science and Engineering
run on this log although often the counting rate from gate 1 was inverted
and put in track 1 so that it looked like a gamma ray log. The heading
will usually tell us what curve we have. The small diameter tool analog
looked the same as the larger tool only the gates were often moved a
little in time or broadened to reduce the statistics on the measurement.
The first Schlumberger Thermal Decay Time (TDT) Log used floating
gates which were not recorded on the log. The logs looked like Fig. 49.
The initial logs only recorded thermal decay time (T) and a CCL (on
extreme right). Latter the cross section curve L was added. T and L are
the inverse. Later a gate 3 which was the background indicator and Gate
4 which was a constant width window were added sometimes. Gate 3
was the background which was subtracted from the output of the two
variable width windows before cross section was calculated. Dresser
Atlas did not subtract the background out but eliminated the background
by not counting low energy gamma rays at the detector. Gate 4 was meant
to show the detail that Dresser Atlas's fixed gates showed. This did not
happen as Schlumberger used a variable length burst on the neutron
source and this reduced the contrast that Gate 4 saw. The variable width
windows on the TDT reduced statistics but sometimes made significant
deviations due to significant changes in borehole environment like
entering multiple casing strings.
The TDT-K was the first small diameter dual detector PNC. This log
added a far spaced detector. See Fig. 50. The T and cross section values
were recorded in the same way as the earlier logs. The ratio curve, which
is meant to be a function of porosity, is the ratio of the counts from the
short and long detectors. N] and F] are counting rates from the near (N)
and far (F) detectors. F3 is the old Gate 3 background gate. The ratio
curve and the cross section curve were designed to give an apparent
porosity and an apparent water salinity from charts like those in Fig. 51.
The liquid filled reservoirs the apparent porosity was many times the
actual porosity. The gas filled reservoirs the apparent porosity is too
low just as' in a conventional neutron porosity log. Water saturation is
the apparent water salinity (WSa) divided by the true water salinity. In
gas zones the water saturation is the apparent porosity divided by the
true porosity. The curves N] and F] were found to be good indicators of
the presence of gas. When N] and F] were normalized in a water or oil
zone, F] would separate from N] and read a higher count rate in a gas
zone or a zone where there was even gas in the annulus between the
casing and formation. See earlier figure 50. Dresser Atlas followed with a
Well Logs Interpretation
F! I
Fig. 50. TDT-K dual detector log (Courtesy Schlumberger).
dual detector NLL although the porosity calibration was not as good as
Schlurnbergers. The TDT-M was introduced in 1981. It is still a dual
detector system only the floating gates to determine cross section are
gone. They now use a series of counting windows to determine the cross
section. They also record cross section from the long spacing rather than
the older short spacing cross section. This new longer spacing is more
like the spacing Dresser Atlas uses.
Resistivity is the electrical resistance of a material in the form of a
cube one metre on the side. Electrical flow in most well logging is through
ionic conduction which makes the measurements independent of the
frequency of the electricity. Reservoir type rocks are defmed as being
78 Encyclopaedia of Petroleum Science and Engineering
L (c.uJ
. $0
r (c.u.)
Fig. 51. TDT-K interpretation charts (Courtesy Schlumberger).
nonclay and non-conductive rock materials. Non-conductive rock
materials are those with resistivity near inftnity (greater than 1,000,000
ohm metres). The resistivity of the fluids generally found in reservoir
rocks are : (1) gas and oil resistivities are inftnite, and (2) water resistivity
Well Logs Interpretation 79
is dependent upon salinity. Pure water has an infinite resistivity. As the
water contains more and more ions the resistivity decreases. The
resistivity of the water is also controlled by temperature. At higher
temperatures the ions can move easily due to the lower water viscosity.
The easier the ions move the lower the resistivity. When water freezes
the ions cannot move and the resistivity is infinite. The relationship
between the water resistivity of the saturating fluid the rock containing
this fluid is given by Archie as :
Ro FR Rw ... (1)
Ro Resistivity of the rock 100 percent
saturated (Sw = 100%)
R w = Resistivity of the saturating water.
F R = Formation resistivity factor.
The formation resistivity factor (F R) is usually related to porosity by
the following equation:
FR = a cjl-m A2)
a constant depending upon pore geometry
m also a pore geometry constant
cjl porosity in a decimal form.
The most common relationship are as :
FR = .62 cjl-2.15
... (3)
Equation (3) is used for sandstones. For normal sandstones over
the porosity range of form 13 to 35 percent is given as :
FR = 1.cjl-2 ... (4)
Equation (4) is used for carbonates and low porosity sandstones.
The exact value to use for m (pore geometry constant) must be determined
from the logs or measurements on core samples. The sandstone pores
and pore samples control m. Some formations having lower m 50 are :
the Nugget, Norphlet and Dinkman. If we have a sandstones with
spherical grains the resistivity will be much lower than we expect. The
carbonate pore geometry influences by non-granular pores. In vuggy
and moldic type porosities the value of m is related to pore geometry.
Fractures will influence the resistivity of a rock by a reduction in
resistivity if the .current flow is along the fracture. If the current flow is
80 Encyclopaedia of Petroleum Science and Engineering
perpendicular to the fracture there will be no change. Water saturation
(irreducible) in reservoir rocks is controlled by the pore sizes and the
surface area of the rocks. Smaller pores, because of capillary pressure
hold water while larger pores do not. Larger surface area also increases
water saturation as the water wet surface area is larger. In sandstones,
higher water saturation, usually goes with smaller grains. Smaller pores
usually go with lower permeability.
In sandstones (and some carbonates) high water saturation do not
always mean the formation will produce water, the formation may be tight
and produce limited amounts of hydrocarbons and no water as all the
water is tied up on the grain surfaces and in the small pores. The effective
shales are clays. They are the montmorillonite, illite and bentonite. The
resistivity of these clays are a function of their CEC (cation exchange
capacity), the water salinity they are associated with and the porosity.
The non-effective shales are kaolinite and chlorite. These in many cases
cannot be detected on well logs as they "look like sand grians". This is
due to their very low CEC.
Resistivity Logs
These logs are often classified according to the depth of investigation
into the formation. Depth of investigation of the different resistivity tools
changes with the resistivity ofthe formation. In general Rxo tools measure
inches into the formation, R; tools measure about a foot into the formation
and R
tools read feet into the formation. The vertical resolution of the
tools is also important. This is particularly important when comparing,
or using values fonn, one log with another, e.g., a log with a vertical
resolution of a few inches must be averaged when comparing with a log
with a verhcal resolution of several feet. Rxo is of course the resistivity
of the flushed zone right next to the borehole. It is assumed that the
has all been removed by the mud fIltrate. The Rxo tools
are all pa type logs in which the current is focussed into the formation
to reduce udcake problems. Rxo curves, because of the shallow depth
of investig tion can be effected by borehole rugosity. The various Rxo
logs are: ( ) microlaterolog (MLL), proximity log (PL), and micro-SFL
(MSFL).The Micro-Spherically Focused Log is a compromise between
the older MLL and PL.
R; is the resistivity of the invaded zone which usually combines the
flushed zone with the zone of transition between the flushed and virgin
zones. This transition zone has both mud filtrate and formation water in
it. The 16 inch or short normal is the oldest of the R; logs. It appears on
Well Logs Interpretation 81
the old Electrical Logs and most of the Induction Electrical Logs. In fresh
muds its depth of investigation is greater than the modem replacements.
The vertical resolution of the tool in resistive beds is about 5 feet. In
conductive beds the vertical resolution is about 3' feet. Spherically
Focused Log (SFL) is Schlumbergers R
log. It has a vertical resolution
of about 2 feet and a depth of investigation of around one foot. Its
borehole influences are about the same as the short normal. The laterolog
8 is a little different than the other laterologs in that it has a high vertical
component to its measurement. This is due to the current return being
just above the tool. The vertical resolution of the laterolog 8 is about 2
feet. The laterolog 8 is replaced by the spherically focused log. Laterologs
have vertical resolutions of about one foot and depths of investigation
of about one foot. The guards are typically one foot long. The laterolog
shallow is a nine electrode device with a 2 foot vertical resolution and
about one foot depths of investigation.
Rt is the resistivity of the uncontaminated reservoir or non-reservoir
rock. The induction log is the most commonly used Rt device in the oil
production. It is primarily a fresh mud tool. In salt muds the invasion
becomes a problem and there are no charts that adequately correct for
invasion of salt mud. The vertical resolution in resistive beds is about 5
feet while the vertical resolution in conductive beds is about 2 feet. The
induction log has the deepest depth of investigation of the modem logs.
The induction reads primarily horizontal resistivity and ignores thin
resistive beds. The laterolog deep is the Rt log used most often in salt
base muds. It has a vertical resolution of about 3 feet. The depth of
investigation is not that of the induction log and thus this tool must be
corrected for invasion most of the time. The invasion corrections are
typically in the 30 to 40 percent range.
Other logs are given below:
1. Microlog : The rnicrolog is a mudcake detector. If there is
mudcake, the formation is presumed to be invaded and thus
permeable. Occasionally in carbonates the rnudcake will form in
the pores away from the well bore and no mudcake will be
detected. The rnicrolog does not work well in salt or gyp base
muds as the mudcake is not strong enough to hold the pad away
from the formation.
2. Porosity Logs : Porosity log measures density and form this
we deduce porosity.
82 Encyclopaedia of Petroleum Science and Engineering
3. Density Log: The density log measures the bulk density of the
formation by bombarding the formation with gamma rays and
measuring the results of Compton Scattering. The bulk density
is corrected for mudcake in front of the logging tool pad. The
measurement is primarily from one to three inches into the
formation. The vertical resolution is in the 2 to 3 foot range.
This measuring system is statistical and thus averaging the
measurement over the vertical resolution tends to reduce this
influence. Also the log measures only on one side of the
borehole. If the formation changes dramatically across the
borehole it wiil show up as changes when multiple passes of
the log are obtained.
4. Neutron Log: The neutron log measures the hydrogen density
of the formation by bombarding the formation with neutrons
and measuring the neutrons resulting from elastic scattering
with the hydrogen. Most neutron logs are borehole
compensated today. The depth of investigation of the
measurement varies with porosity (hydrogen content). In high
porosity formations the depth of investigation is about 8 inches
while in low porosity formations it is 14 inches. The vertical
resolution of the measurement is about 3 feet. The measurement
is statistical.
5. Acoustic (Sonic) Log: The acoustic log measures the time for
a high frequency acoustic wave to travel parallel to the borehole
axis to travel one foot. The vertical resolution is normally 2 feet
and the depth of investigation is 8 to 12 inches.
6. Caliper Logs: The major use of caliper logs is to evaluate the
environment under which a basic logging measurement is made.
An accurate determination of hole size from caliper logs requires
some knowledge of the characteristics of the tool used. In round
holes, all Caliper logs measure the hole size properly while in
non-round holes, which commonly occur when there is caving,
the one and two-armed calipers often measure larger diameters
than the three and four-armed calipers which are in common use.
Dual type caliper logs measure two orthogonal hole diameters,
giving some indication of the hole shape and a good
measurement of the hole size.
Well Logs Interpretation 83
The size, type and pressure of the actual contacting mechanism of
the caliper log also influences the measurement of hole conditions. Small
contacts measure more details of the borehole wall than do large contacts.
Similarly, high pressure contacts cut through the mudcake and measure
larger hole diameters than low pressure contacts which do not cut through
the mudcake. Caliper logs can give us valuable information about the
borehole size and shape. As hole size and shape should be controlled
by formation rock properties such as stress and geological conditions,
caliper logs should be used to aid in evaluation of rock properties of
formations drilled. Caliper logs are very informative and should be
analysed closely by people interested in the hole and the formations
around the hole.
Resistivity-Porosity Crossplots
Resistivity-porosity crossplots are efforts to obtain more information
or different information than from techniques like the R,,'11 techniques.
These resistivity-porosity crossplots are generally used where porosity
varies significantly as in these cases the information obtained is more
complete than a typical R"Y1 analysis. The two types of resistivity-porosity
crossplots used are, the log-log (often called the Pickett) plot and the
RPC (resistivity-porosity crossplot often called the Hingle) crossplot.
These crossplots are significantly different and yield different information.
Both these crossplots are based on the Archie equation. Logarithm-
logarithm (Pickett) plot is important. The prime purpose of this plot is to
obtain an m for the FR-porosity relationship. Because it is graphical
technique it also present a picture in which we can often see groupings
of data caused by the variations of rock texture (pore sizes, etc.). The
Archie Equation is given as :
2 = FRRw (1)
w R

Taking logarithm of equation (1), we get:
2 log Sw = log FR + log Rw -log R
.. (2)
Substituting FR = a ~ - m in equation (2), we get:
log Rt = -m log ~ + log (aR) - 2 log Sw ... (3)
For a zone with Sw = 100 percent, the equation (3) becomes:
log Rt = -n/ log ~ + log (aR,,) ... (4)
Equation (4) shows a statistical line on log-log paper in the form as :
S-4 Encyclopaedia of Petroleum Science and Engineering
Y = Inx+b ... (5)
This means that if we have porosity and resistivity logs in a water
zone the data taken from them will plot a straight line on a log-log paper
as long as In is constant. The slope of the line will be controlled by m.
See Fig. 52. The intersection of the line through the data points and 100
percent porosity will be a.R
Since a is usually unknown it is usually
assumed to be 1.0. Thus the intersection is at Rw. On log-log paper we
determine the slope by a ruler. Hydrocarbon bearing zones plot to the
right of the water (or Ro) line. Constant water saturation lines plot to the
right of the Ro line and parallel to it. Any Sw monograph or the equations
can be used to calculate the position of the Sw lines. The equation looks
Rt = ROS-2
, w
... (6)
At constant porosity Ro is then a number on the plot. Using above
figure and a porosity of20 percent, Ro is then 3.8 ohm m Sw = 50 percent
is then located at :
38 38 .
Rt = --2 = -- = 15.2 at 20 percent poroSIty
0.5 0.25
At any other porosity the same technique is used. All these values
for Sw = 50 percent will end up being parallel to the Ro line only with
resistivities 4 times higher.
Shaly zones quite often change m with changes in shaliness. The
Ro line for a zone with changing shaliness and Sw = 100 percent will not
extrapolate back to Rw. Small errors or shifts make large differences on
log-log graphs. Errors in porosity can result in curved rather than straight
Ro lines. Pickett showed that an error in matrix travel time or density can
cause this curvature. The slope of the Ro line may change from well to
well if the logs are not well calibrated. Consistent errors will cause
consistent changes in m. The higher the quality the data the better the
log-log plot is for solving problems.
The Resistivity-Porosity Crossplot (RPC) requires special graph
paper that is designed for particular formation resistivity factor-porosity
relationships. The RPC paper is designed so that a plot of resistivity
and some linear function of porosity, like density, will be linear in water
zones and zones of constant water saturation. In reality it is a plot of
porosity along the horizontal scale versus water filled porosity on the
vertical or resistivity scale. When the water saturation is 100 percent both
the porosity and water filled porosity are the same. In intervals with water
; j
" I
2 : !: .. 1
t ;;: ..
j .. '''" .. ,
l i!' I' ~
l -: ... ..! ! . ~ ..
,1 .2
:" 'I' -., f 1,,'1, l
". :"<,UHLtli'!. ~ , 11 t"7J ' , ,
: ,_ 11 t -f. ; ~ ~ I i
.3.4 ,6 .8 1
j .;
ReFli.Gtiv1 t}'
'j ; ,1 j
, : c : ~ , U -j
Fig. 52. A log-log resistivity and porosity crossplot (After Hilchie, 1982).
, ~ , : ,
86 Encyclopaedia of Petroleum Science and Engineering
saturations less than lOO percent water filled porosity is less than the
porosity. This is related to the water saturation which is given below:
Sw = ~ ; ... (7)
where ~ w is the fraction of total rock that is filled with water and ~ is
porosity. Fig. 53 is a schematic of an RPC plot. Since ~ w is not convenient
to plot it is converted to resistivity by the following equation:
... (8)
Equation (8) shows that at infinite resistivity the water filled porosity
is zero. RPC paper for various m's commonly used in log interpretation
0w = ~
0 W<0
Fig. 53. Schematic RPC plot.
Important points ofRPCAlgorithrn(Hilchie, 1982) is given below:
1. Read the resistivity and porosity log values from the logs for
the interval to the analyzed. Be sure to cover a complete range
of porosities so that a good Ro line can be drawn. The
porosities do not need to be productive. Porosities of 1 percent
very effectively tie down the low porosity range on the Ro line.
2. Set up scales on the appropriate RPC paper, i.e., choose the
proper m. Make sure the horizontal porosity scale goes from
zero porosity to the highest porosity we read off the log. If we
have a density and neutron (or acoustic and neutron) plot the
porosity obtained from the density-neutron crossplot. Scale the
resistivity scale on the RPC so that the lowest resistivity is near
the top of the graph. Change the RPC resistivity scale by
multiplying or dividing by a constant to obtain a scale where
the lowest resistivity is close to the top of the RPC paper.
3. Read the log data and plot it on the RPC paper. Use a number
for each zone so that you can fmd the zone later. Plot porosity
increasing to the right.
Well Logs Interpretation 87
4. Water zone (if any) data will plot in the upper and left edge of
the envelop formed by the data. Draw a straight line through
an average of the left edge data. The line should go from the
base line (infInite resistivity) to the lowest resistivity plotted.
5. Layout a porosity scale. Use the matrix if we plotted density or
travel time, to construct porosity scale.
6. The slope of the Ro line is controlled by Rw. To check that the
Rw is reasonable, i.e., in a water zone, you must use some
porosity value and the equivalent Ro value from the line.
7. All intervals with water saturations less than 100 percent will
fall below the Ro line. All the water saturation lines go through
the matrix point.
The log-log plot gives us m and if we are lucky an indication of Rw.
The RPC gives us matrix, or if we wish porosity control, and if we are
lucky Rw. The log-log plot is sensitive to small porosity changes in the
low porosity range. The RPC is sensitive to small resistivity changes at
high porosity. Both are relatively sensitive to Rw variations. In both cases
we need to know Rw to do a good job although often the crossplots will
tell us Rw. Both crossplots require high grade data to work effectively.
Thin resistive beds will throw both plots into erroneous answers if the
thin beds are not detected during the analysis. With both crossplots
changes in reservoir texture show up as group lings at different locations
on the plot. As both plots accentuate, different parameters the two may
be used in combination. The combined use of log-log and RPC plots is
often very advantageous. This combined use age requires a good
knowledge of the Rw otherwise we can sometimes fall into a trap. The
combined useage is best done with a computer. The computer allows
the construction of RPC paper with any m. The m must be constant for
all RPC and log-log plots. The easiest way is to start with the RPC and
then having established porosity control go to the log-log plot to
establish m and then go back to the RPC to refIne porosity control, etc.
Resistivity Ratio Methods
Conventional interpretations rely on everything staying the same over
the interval evaluated. Everything being Rw and the textural properties of
the rocks. One way is to measure the resistivity in the completely invaded
zone (Rxo) and compare it with the resistivity of the virgin zone. The
only problem with this technique is that the zone must be invaded enough
to be able to make the comparison. If the formation does not have
88 Encyclopaedia of Petroleum Science and Engineering
adequate invasion this system does not work. Sw is given by the following
RxO RW)5/8
Sw = Rt Rmf ... (1)
Equation (1) does not require a porosity to formation resistivity factor
conversion and thus is not bothered by m variations. Sw can be given
by another equation as :
R . ~
S = -'.- ... (2)
w R
Where Z is the decimal fraction of formation water left in the invaded
zone (usually assumed to be 0.075). Z is the function of invasion depth.
Changes of invasion from well to well will cause variations RIR,. In any
given well over a limited vertical distance invasion is constant. With
resistivity ratio charts the zones must be invaded. If we run into a zone
that is not invaded the ratio will decrease (in fresh mud) and look like
hydrocarbons. Usually in tight zones Ri and R
are close to being equal.
With the RIR
techniques, in water zones that are invaded the RIR
will be essentially constant with Sw = 100 percent. The ratio will reduce
to about 50 percent or less where we have Sw less than 60 percent. This
makes a good qualitative way to look at the logs. The modem logs which
use SFL, LL, etc. for Ri work better than the older logs that use the 16
inch normal as the newer tools do not see as deep as the 16 inch normal.
There is better defInition of Ri"
On modem logs presented with resistivity on a logarithmic scale,
the separation between the Ri and R
curves is the ratio, e.g., on a full
dual induction log if the RIR
ratio is 10, the Ri and R
curves will always
be 1.25 inches apart. In shaly formations the RIR
ratio is reduced over
what it would be under the same conditions in a clean formation. A quick
rule of thumb is that if the formation has a shale volume of 30 percent,
the ratio will be reduced 30 percent. What this means on a Fig. 54 if we
put in the SP that will give us the correct R
' and the formation is shaly
the apparent Sw will be 70 percent. But if we put in the apparent SP from
the shaly formation, with the apparent R
and R,. The Sw will calculate to
be about 100 percent unless hydrocarbon suppression is large. The
technique tends to be self compensating for shale if we put in the actual
data unless hydrocarbon suppression is severe. Use of the gamma ray
to normalize the SP would make the system self compensating. Fig. 55
shows a viking sandstone water bearing zone. The zone is shalying
Well Logs Interpretation
downward at a fairly constant rate. R/R
ratio is reducing with shaliness.
Below we see some points plotted for the interval from top to bottom.
The very top interval is well off the plot of earlier Fig. 54. This is probably
due to the difference in vertical resolution of the R
(LL8) and R
devices. The rest of the points tend to converge to the Sw = lOO percent
line as plotted actual SP versus R/ R,.
Shaly Sandstone Interpretation
The problem with shaly formation is that the water saturation we
calculate from the resistivity logs is too high in that it does not represent
I:"" AS 10:-:
RM: /11...: SP
. ,0
_ 10

L- .10--
;... .. 10-- ,
T 10 lIS 10 10: 40 50
SP -60 mv. z I.S - 3Jt
Fig. 54. Resistivity ratio technique R/Rt (After Hi1chie, 1982).
: : :
I ",;
I '.: :-:
I: :: : , i i
: : : : : : .

, .
; .
i :
I-J. : : ;
t 't. .....
III-I'll"'] o.
I! o
. , .
: . l ! _ I
. . -:l
,1 I I T f-: ;.
.. -.. 1.11" ,
<t .
1 I
- ,---<.
;. :
.. ' ..
: _. .. u
IS t<:('
Fig. 55. An example of resistivity ratio change in a water sand with Shaliness (After Hilchie, 1982).






Well Logs Interpretation 91
the time water saturation in the pores. This is caused by the shale (or
clay), which has a lower resistivity than the sand grains. Porosity logs
are often influenced by shale so that the calculated porosities are wrong.
In shally sandstone it is difficult to determine Rw and most important is
that the shale often influences the permeability. Usually with no shale
corrections, the water saturation is too high, making the zone look like it
could be non-productive, and the porosity is also too high or too low
depending upon the logs used. The high CEC (cation exchange capacity)
shales, montmorillonite, bentonite and illite an effective shales, while
kaolinite and chlorite are noneffective shales. Montmorillonite has a
resistivity of about 0.7 to l.5 ohm m at 77P' The porosity logs all show
montmorillonite to look like higher porosity than there actually is. Thus
in a sand of lO percent porosity the shale will make the porosity appear
higher than the actual porosity. In high porosities, like 30 percent the
density log will read lower than true porosity while the neutron will appear
to have higher porosity than the true porosity. The acoustic log response
is more complex as the acoustic log influences are determine by where
the shale is rather than the apparent travel time of the shale. In general,
if the shale is purely in the pore space, the acoustic log will not see the
shale. If the shale is in layers that are perpendicular to the path of the
acoustic wave propogation the acoustic log will see the shale. In this
case it will see the compacted shale. The travel time of the acoustic wave
in the shale will of course be influenced significantly by the degree of
compaction of shale.
Illite on the gamma ray looks about as radioactive as montmorillonite
as it is contains radioactive potassium as well as CEC. It looks like a
shale on the SP as it is an effective shale. The resistivity of illite it higher
than montmorillonite due to its lower CEC.A resistivity of illite is of 1 to
3 ohm m. The m for illite is about 2.1 which means it acts much like a
sand. The density log sees illite as a sandstone porosity of less than
zero. A large amount of illite in a sandstone will result in the density log
porosity being lower than the real porosity. At 30 percent illite the porosity
calculated will be about 2 porosity percent too low which could be serious
at the 8 to 9 percent porosity range where we are trying to decide if the
rock is tight or not. The acoustic and neutron logs see illite much like
montmorillonie. Illite thus results in larger separations on the density
neutron log combination than montmorillonite. It looks shalier. Kaolinite
is one of the noneffective shales. On the gamma ray, SP and resistivity
logs it looks like sand grains. Using these three logs we would expect
92 Encyclopaedia of Petroleum Science and Engineering
the reservoir to be a clean sandstone. The m factor for kaolinite is 1.87
and thus still reacts like a sand grain. The higher surface area and smaller
"grain" size will result in an increase in the water saturation but acts just
like a very fine grained sand. The density log sees kaolinite as being
very close to that for a sand. The neutron log shows kaolinite as 40+
porosity. Thus, in a bed with a great deal of kaolinite the neutron indicates
a much higher porosity than the density log. The density neutron
combination looks shaly. Kaolinite on an SP, gannna ray, resistivity, density
and neutron log combination looks anomalous. Everything looks clean
except the neutron log. We can calculate Rw from the SP with good results
and the density log give porosities that agree with the core analysis.
The acoustic log looks the same for montmorillonite and illite only with
possibly a little shorter travel time for as the formations become more
Chlorite is generally a non-effective shale. It looks like sand on the
SP and gamma ray just as kaolinite does. The resistivity is usually just
like a sand grain although sometimes iron appears in the matrix and the
resistivity is lower. Chlorite looks like a porosity less than zero on the
density log. The matrix density is significantly heavier than sandstone,
e.g., from 2.76 to 3 gm/cc which means that with chlorite in place the
density log porosity can be significantly too low. The neutron and
acoustic log see chlorite as high porosity. The iron effects should be
compensated for when a density neutron crossplot porosity is obtained.
Shaly Sandstone Interpretation Factors
The various factors influence the interpretation of shaly sandstones.
The water salinity and volume of effective shale significantly influence
the accuracy of shaly sandstone interpretations. The effective shales,
because of their CEC, attract the ions from the formation water. In a very
salty water (i.e., 100,000 ppm or more) the ions of the centre of the pore
are equal to or greater than the density of ions that are adsorbed on the
CEC sites on the effective shales. Fig. 56 shows a schematic of a pore
space filled with very salty water. The water in the centre of the pore is
free to move while the ions adsorbed on the effective shales are not free
to move. Oil or gas moving into this pore space would displace the water
and associated ions in the centre of the pore space leaving the ions
adsorbed on the shale particles and the water wetting the sites of the
pore. Bound water refers to the water associated with the effective clays,
free water is the water that can move in the centre of the pore space and
the combination of these two is mixed water. In very salty water the free
water is either the same or saltier than the bound water. In a oil or gas
Well Logs Interpretation 93
sand where the free water is displaced, the effective shale acts like a low
resistivity solid added to the pore space which reduce the formation
resistivity. The effective resistivity of the clay is probably higher than
the water resistivity. This disturbs the water saturation calculation. In
relatively fresh water (10,000 to 30,000 ppm range) we can end up with a
situation like that shown in Fig. 57. Most of the ions are adsorbed on
the clay sites and the free water appears less salty than the adsorbed or
bound water. When the oil or gas displaces the free water, the overall
resistivity of the pore is not increased nearly as much as in the salty
(only positive
shown but there would
negative 'ions also)
Fig. 56. A shaly sand pore space filled with salty water.
+- ions. (only pOSitiVe
shown) .
Fig. 57. A shaly sand pore space with low salinity water.
water case. In fact when interpreting this type of shaly sand the analyst
is often forced to assume that the water has changed from relatively fresh
in the water zone to salty in the hydrocarbon bearing zone. If there are
not enough ions to satisfy all the effective shale sites water obtained
from drill stem tests or production test may be very fresh as the clays
filter the ions out of the water as it moves through the formation. In this
case the water catalog values show the water resistivity to be two high,
e.g., Cretaceous sands. The relatively fresh water shaly sands are'more
difficult to interpret than the salty water shaly sands. A good value of
Rw for the shaly sand is a must for the reasonable shaly sand
interpretation as it is for any interpretation.
In shaly sandstone we must first decide if the shale is effective or
non-effective. Correction for effective shales is the conventional
approach to shaly sand interpretation. This requires a correction that
requires volume of shale and the resistivity of the shale, or CEC (cation
94 Encyclopaedia of Petroleum Science and Engineering
exchange capacity) or the amount of bound water and its resistivity. A
correction for the amount of non-effective shale would only require an
estimate of the amount of non-effective shale and its influence
(associated water). The gamma ray has been one of the classical ways
of obtaining the volume of shale. The gamma ray thus is an indicator of
effective shales of no outside influences interfere. The SP reduction due
to shaliness is due to effective shales and not non-effective shales.
Additionally the SP, when hydrocarbons are present, and the formation
is shaly, is reduced due to hydrocarbon suppression. A higher volume
from the gamma ray or density-neutron crossplot indicates other
influences than effective shale on the measurements. Obtaining the
correct porosity is important from two points : one the volume of the
reservoir and, two, the porosity is used in most of the shafy sand
interpretation models that are used to calculate water saturation. The
correction of the density log for shale content is relatively easy and
accurate if we know the shale volume and the type of shale. A good
shaly sand interpretation for porosity requires that the shale be a single
clay. A mixture of effective and non-effective clays can make the picture
very complex and unsolvable in some cases. The acoustic log is the most
difficult of the porosity devices to correct for shale content. The position
of the shale or clay in the rock matrix is very important. If the shale is
truly dispersed in the pore space the acoustic log will not see the shale
and the porosity will be the porosity calculated from the acoustic log
minus the fraction of pore space filled with shale. If the shale is in a
structural position, i.e., lumps of shale in a load bearing position
(replacing sand grains) the acoustic log will probably not see the shale
unless there is a lot of shale and it is disseminated throughout the bed
so that it looks homogeneous. We need excellent geological control to
obtain porosity from the acoustic log in a shaly sandstone. Do not use
the acoustic log for porosity in shaly sandstones unless we have good
control of the rocks. We have cores and do not need the acoustic log
for porosity.
The common practice ofusmg the shale resistivity from the resistivity
log in an adjacent formation is practical if the shale is laminated. If the
shale is dispersed in the pore space and not compacted or contaminated
(not pure) it would seem that the pure shale resistivity should be used.
The numbers quoted for montmorillonite (0.7 to 1.5 ohm m at 77F) and
illite (1 to 3 ohm m at 77F) seem tlike the numbers that should be used
in shaly sand interpretation. CEC measurements are made on rock samples
and not by logging devices. The sample used for most CEC
Well Logs Interpretation 95
measurements is very small. Only in relatively homogenous reservoirs
can we effectively relate the CEC measured on the small sample to the
logs which average a great deal to rock. Models are used to determine
water saturation from resistivity. For more complete discussion and more
models please refer to "A comparative look at water saturation
computations in shaly sands" by Fertl and Hammack, 12th SPWLA Trans.
1971. The Simandoux equation is used most and produces the water
saturations that has never been proven to be the case. The merits of
any particular model should be based on how well the model fits the
particular geological conditions of the reservoir. The three most used
shaly sand interpretation techniques are : Simandoux, Waxman-Smith, and
the Dual Water. Simandoux equation has been the most used by service
companies in their interval computer programs. Waxman and Smits
developed a Shaly sandstone model using CEC as the input. The Dual
Water Model consists of recognising that the pore space is filled with
two different waters, free water (Rw[) and bound water (R
) on the
effective shales. Rw is calculated as the combination of the bound and
free water. The amount of effective shale controls the amount of bound
water so the resistivity of the mix of bound and free water (Rwm) changes
as the shaliness changes. The adjacent shale or shaly water zone is used
to calculate R
In a water zone the sum of the free water and bound
water equals the porosity.
Temperature Logs
If we could only run one log in an empty hole which is producing
gas it should be the temperature log. Gas flowing from a formation into
an empty hole cools due to expansion. This can be seen on temperature
logs. Thus with a temperature log we can pinpoint the source of the gas.
The degree of cooling depends upon the reservoir pressure, the
permeability, the reservoir thickness and the volume of gas produced.
The higher the production rate the larger the temperature anomally
although sometimes the anomally is decreased by heating of the gas as
it flows Qrrough the formation. The determination of the boundaries of
the gas producing zones requires a knowledge of the shape of the curve
created by the gas. Fig. 58 shows a temperature log for a single gas zone.
The flowing temperature well above the gas zone is higher than the
geothermal gradient. The temperature in the gas producing zone is lower
than the geothermal gradient. Note the smooth transition between the
gas producing zone and the temperature well above the zone. Also notice
the sharp increase in temperature below the producing zone and the
return to the geothermal gradient. Differential temperature logs are also
96 Encyclopaedia of Petroleum Science and Engineering
'1-. "M ... ,. LOll
Sf.lN: r ....... , .... ,. t.,..
GnZ ...
Fig. 58. Gas expansion effect on the temperature log (Courtesy Walex).
often run in empty holes to detect gas producing zones. Fig. 59 shows
both a temperature and a differential temperature log. The differential
temperature log is a recording of the differential or slope of the temperature
log. Although the differential temperaru,e log makes it easier to fmd the
anomallies the temperature log better defmes the producing zone. With
just a differential temperature log it is not possible to determine the relative
production rates or the boundaries of the production zones. In this figure
the gas producing zone is thin as marked on the log. On the temperature
log each entry of gas from a different zone causes a reduction in the
temperature. Thus in a case where there are multiple zones producing
gas we will see a temperature reduction at each of these zones. See
Fig. 60.
Tying WelJ Data
If a seismic section can be tied directly to well information, the
synthetic seismogram or VSP (with the correct polarity and frequency
Well Logs Interpretation
. .
~ . ...... , .
. --
. --
Fig. 59. Temperature and differential temperature logs in an empty hole .
I If \'
c..lot .. ,,,.,,, ' . i J I I . ~ ' f .. '
I ''''''II
Co c.,,, .... , .. ,
l1li c. ... "0.-
Fig. 60. Temperature log with multiple gas producing zones.
a b c d
tldd se.ctlon With Input Density
density wavele. log
Field section
Sand. and """lois
wlrh coal 541ams
C arrowed j
1'''' C.lll fAC' (JU"
r y
O(,I .. ""t., .nd
Fig. 61. Example of borehole tie from Western Canada. Synthetic seismograms are (b) and (f). Displays (b) to (f) are supplied into the
field section (a). (Courtesy Digitech Ltd.).
Well Logs Interpretation 99
bandwidth) should be overlain or spliced in at the appropriate location.
The earth acts as a filter for seismic pulses, so it is unreasonable to expect
a perfect match in amplitude, frequency and phase. Where there is a good
fit, often a time mis-tie will be found due to errors in any of the applicable
corrections for NMO, weathering, elevations, depths of guns, cables, etc.
Other mis-tie effects may be induced by phase distortion in the recording
or playback instrumentation. Correlation should therefore be made on
an interval best-fit basis as has to be done with the synthetic seismogram
which has been produced from an uncalibrated sonic log. Static errors
should always be investigated but may be unresolved. In the absence
of, or in conjunction with a synthetic seismogram, the logged velocity
trace from a well velocity surveyor sonic can be overlain on or spliced
into a seismic section and velocity contrasts aligned with appropriate
peaks and troughs. See Fig. 61. Where the above are not available,
interval velocities can be plotted on a suitable time scale from a
continuous velocity log and compared as above. If neither synthetics
nor well velocity surveys are available, the integration on a sonic log
can be plotted manually as an interval velocity curve and used similarly.
If no sonic log are available, a formation density log can be used to give
a very qualitative indication of the relationship between the geological
section penetrated by a well and the equivalent seismic section. If there
is some confidence in the velocities derived regionally from seismic data,
the gamma-ray or formation density trace can be converted, depth to
time, and empirical correlations made. When seismic lines do not tie
directly to coreholes, various approaches can be adopted for reflection
identification but mainly in this situation there is a considerable reliance
on intuition and there can be no substitute for a good borehole tie.
1. Al-saif et. aI., 1979; Analysis of pulsed neutron decay time logs
in acidized carbonate formations, SPEJ, VoLlO, No.1.
2. Berry W.R., Head M. and Mougne, 1979; Dielectric constant
logging: A progress report; SPWLA 20th Ann. Log. Symp.
Trans., June.
3. Clavier et. at., 1976; Effects of pyrite on resistivity and other
logging measurements; 17th SPWLA Symp. Trans. Paper HH.
4. Coolidge and Gramson, 1960; Present status of nuclear
magnetism logging; presented at SPE Form. Eval. Symp.,
Huston, Nov., paper 1645 G.
5. Coolidge, 1962; Nuclear magnetism logging; Oil & Gas Jour.,
100 Encyclopaedia of Petroleum Science and Engineering
6. Herrich et. ai., 1978; An improved nuclear magnetion logging
system; presented in Las Vegas, Sept., SPE paper 8361.
7. Hi1chie D.W., 1982; Advanced well log interpretation; Douglas
W. Hilchile, Inc., P.O. Box 785, Golden Colorado 80402.
8. Lock G.A. and Hoyer W.A., 1974; Carbon-oxygen (C/O) log:
use and interpretation; Jour. Of Pet. Tech., Sept., SPE of AIME
paper 4639.
9. Loren, 1972; Permeability estimates from NML measurements;
Jour. Pet. Tech., August.
10. Oliver D.W. et. a/., 1981; Continuous carbon/oxygen (C/O)
logging instrumentation, interpretive concepts and field
applications; SPWLA 22 Ann. Log. Sym. Trans., June.
11 Serra et. ai., 1980; Natural gamma ray spectra; SPWLA 21st Ann.
Syn. Trans., Paper Q.
12. Tittman J., 1956; Radiation logging; Univ. of Kansas Pet. Engr.
Con f., April.
13. Wharton et. ai., 1980; Electromagnetic propagation logging:
Advances in technique and interpretation; presented SPE 55th
Ann. Mtg., DalIas, Sept., paper 9267.
Palynology, a word coined by Hyde and Williams (1944), was defined
by them as "the study of pollen and other spores and their dispersal,
and applications thereof'. The term includes both modem and fossil
pollen and spores. Fossils are elements of a continuum of once-living
organisms whose succession was shaped by organic evolution.
Palynology depends mainly on four characteristics of pollen and spores:
(1) their greater resistance to degradation than most other plant parts,
thus facilitating their survival as fossils, (2) their small size, mostly less
than 200 microns, so that they are transported and deposited as
sedimentary particles, (3) their morphological complexity, so that can be
distinguished and characterized, and (4) their production in enormous
numbers, which facilitates recovery of statistically significant
Fossil plants have been found in rocks ranging in age from the
Precambrian to the Recent. Spores are among the earliest structurally
preserved remains of plant life and accompany material that is probably
derived from bacteria, algae, and perhaps fungi. The fIrst unequivocal
plant spores bearing trilete sutures are found in rocks of Silurian age.
The advent of vascular tissues, a most signifIcant step in land-plant
evolution, occurred at about the same time. Vascular and reproductive
structures may have evolved more or less concurrently, but the two
developments probably were essentially, independent of one another.
Heterospory (the development of megaspores and microspores) is fIrst
noted in the fossil record of the Devonian Period. Heterospory is the
prologue to development of the seed. Two important structure types,
monosulcate and bisaccate pollen, fIrst appear in the Pennsylvanian
102 Encyclopaedia of Petroleum Science and Engineering
Period. Monosulcate pollen became established as characteristic in
the cycadophytes. Bisaccate pollen is common in the conifers. A
significant aspect of both monosulcate and bisaccate pollen is that the
aperture for the emergence of the prothallial tissue is on the distal surface.
In trilete and monolate spores the aperture is along the suture on the
proximal side of the spore. The last prominent evolutionary milestone
was the appearance of recognizable, true angiospermous pollen. The
palynological record shows recognizable angiosperm pollen in the late
early Cretaceous.
There are three major groups of phenomena from which inferences
concerning the age of rocks can be drawn: (1) sediments and processes
of sedimentation, (2) the record of evolution of life, and (3) rates of
radioactive decay. Table 1 shows geological time scale. Palynological
studies can be approached from the viewpoint of botany, with emphasis
on the plant relationships, or from the geological perspective, with
emphasis on biostratigraphy. Adequacy requires a knowledge of both
fields. Significant scientific contributions have demonstrated the value
of palynology, and its future expansion will yield further contributions
in the fields of plant systematics, plant geography, paleoclimatology, and
a better understanding of the history of the plant kingdom Palynology
will furnish more refined and more extensive geologic and stratigraphic
data as its coverage enlarges.
Detailed Encyclopaedia
This encyclopaedia is arranged in alphabetical order. The detailed
encyclopaedia is given below :
The acritarchs comprise unicellular or apparently unicellular
microfossils that consist of a test, composed of organic substances,
enclosing a central cavity. Shape, symmetry, structure, and ornamentation
are varied. An inner body may be present or not; where present it may
be connected to the outer wall by varied means or it may lack such
connection. The test may be unruptured or may open by formation of a
pylome of varied design. Acritarchs include many of the fossils formerly
known as hystrichospheres, especially those from the Paleozoic. Many
types bear spine-like processes and superficially resemble the
dinoflagellate hystrichospheres. Acritarchs are widespread in carbonates,
cherts, and fme clastic sediments from Proterozoic and younger horizons.
Geological Time Scale ;:s
Beginning of
System (s) Stage (million years) Duration
Series Kulp Holms (million years)
or or ......
Era Period (Epoch) Age (1961) (/965) Helmes (1965)
Quaternary Recent
Pleistocene 2 or 3 2 or 3 ;:s
Pliocene 13 12 9 or 10 ~
Miocene 25 25 13
Cenozoic Tertiary Oligocene 36 40 15
upper2 45
Eocene middle2 52
lower 58 60 20
Paleocene 63 70 10
Mesozoic Maestrichtian 72
Upper (Late) Santonian 84
Cretaceous Coniacian 90
Turonian 65
Cenomanian 110
Albian 120
Lower (Early) Aptian
Neocomian 135 135
Upper (Late) to-'
Bathonian 166 C/.j
Beginning of
Interval! 01:>-
System (s) Stage (million years) Duration
or Series or Kulp Holms (million years)
Era Period (Epoch) Age (1961) (1965) Helmes (1965)
Jurassic Middle (Middle) Bajocian
Lower (Early) 181 180
Upper (Late) 200
Triassic Middle (Middle)
Lower {Early} {230) 225 S
Upper (Late)
Pennian 260 45
Lower (Early) 280 270 .....
Pennsylvanian Visean 320
iferous Mississippian Toumasian 345 350
Upper (Late) (365) ~
Devonian Middle (Middle) 390 C"'-l
Lower (Early) 405 400
~ .
Silurian (425) 440 40
Upper (Late)
Trenton 445
Ordovician Middle (Middle) 60
Lower (Early) 500 500
Upper (Late) 530 ~
Cambrian Middle (Middle) 100
Lower (Early) 600
Fundamentals of Palynology 105
The acritarchs constitute a "catch-all" utilitarian category of organic
microfossils. They are morphologically varied and offten abundant
microfossils. General affinities of these microfossils with the algae have
been suggested by Eisenack (1962). These fossils occur in rocks of many
lithologies, shales and limestones having yielded the richest
assemblages. Most appear to have been elements of the marine plankton,
although freshwater examples have been reported. The essential
morphological feature of an acritarch is a central cavity closed off from
the exterior by a wall of primarily organic composition. Spines or other
projecting structures occur on many acritarchs. They commonly vary in
number within a single species and may also vary in length on a single
specimen. Surface structures that project appreciably from the central
body fall generally into two categories. Processes are spine like to
colunmar projections and may have simple to elaborately branched tips,
free or interconnected. Septa are membranous structures that rise more
or less at right angles to the surface of the central body. The variety of
form and structure evidenced by the acritarchs seems virtually limitless.
Acritarchs are classified in many subgroups : (1) Acanthomorphitae,
(2) Polygonomorphitae, (3) Herkomorphitae, (4) Sphaeromorphitae,
(5) Netromorphite (6) Pteromorphitae, Prismatomorphitae, and
(7) Diacromorphitae. See Fig. 1.
Most of the acritarchs have a wall composed of one principal layer.
However, an assortment of organic microfossils, especially from the
Jurassic and Cretaceous, consist of an outerwall about a distinct inner
body. They may be further categorised by differences in shape. Although
critical identifying features are lacking, distinctive external shapes and
traces of openings, which may prove identifiable as archeopyles on
closer study, suggest that some of these fossils may be dinoflagellates.
Wallodinium is represented by several Jurassic species in Europe and
Australia. It is cylindrical and is truncated by an opening at one end. A
large inneJ: body of somewhat similar shape is enclosed.
The chiefly vase-shaped tests of Chitinozoa range from 30 to 1500
microns in length and resemble pseudochitin in composition. They are
widespread in Ordovician to Devonian marine sediments and have proved
highly useful for stratigraphic zonation in some areas. Genera and species
. are distinguished chiefly by differences in the shape of the test, presence
and structure of spines and other projections, and structures associates
106 Encyclopaedia of Petroleum Science and Engineering
Fig. 1. Representative acritarchs (After Tschudy and Scott, 1969).
Fundamentals of Palynology 107
with a single terminal aperture. The Chitinozoa, named by Eisenack (1931 ),
comprise an assortment of essentially vaselike, commonly dark-coloured,
organic microfossils in lower Paleozoic marine sediments. They are readily
distinguished from associated fossils and seem to constitute a closely
interrelated groups. Specimens usually appear black or dark brown except
in the thinnest areas, but, with best preservation, they are transparent
and reveal internal structures. The larger specimens can be separated
easily from fine debris by differential settling or heavy liquid treatment
and then picked individually from concentrated residues with a fme
pipette under a low-power microscope. The morphological features of
Chitinozoa are shown in Fig. 2. The typically vaselike tests range from
nearly spherical to irregularly cylindrical. The cavity of the chamber may
open directly through the terminal aperture, or a distinct neck may
separate the two. Externally the base and sides of the test may merge
along a smoothly convex surface. Alternatively the contact may be
marked by a distinct angulation or ridge, the carina, or by a row of basal
horns, or appendages. The carina is rarely extended into an elaborate
network. The basal horns are variable in size, number, and structure. The
base commonly bears at its centre either a small mucron, which is a
nipplelike elevation usually with a central perforation, or a larger, tubular
structlp"e called the copula. The internal structures of chitinozoans and
tOnI .... '
II" I - Coltnttt
i' "" , j I
.'\4 I 4
\\"',-1 "
:' .. ' J II
'lop. , If
~ . .\. --
'" "" 'I
~ \ \ I,
.. ~ .. ~ ~
Ba ..
(a) IAbOtal pol"
_ - Appendage
Fig. 2. Terminology of Chitinozoa.
108 Encyclopaedia of Petroleum Science and Engineering
the devices that appear to have linked together successive members of
chainlike "colonies" are relatively new discoveries.
First described from the Ordovician and Silurian of Baltic Europe,
Chitinozoa have now been reported from Cambrian-Ordovician to upper
Devonian rocks of France, North Africa, and North America.
Clear evolutionary trends in the Chitinozoa have been recognised. They
were perhaps attached to floating objects if not themselves truly benthic.
The Copulida and the Acopulida families are distinguished within
each suborder on the basis of the nature of the connecting deyice
or the presence or absence of special ornamentation around the tJasal
Other organic microfossils occur in palynological preparationS are
ofTasmanites, Pediastrum and Ophiobolus.
Classification of Plants
A primary breakdown of the plant kingdom on a structural basis
yields two great division: (1) the nonvascular, and (2) the vascular plants.
Further subdividing is necessary. The following categories for additional
subdivision of the plant kingdom and their relative ranks are designated
by the "International Code of Botanical Nomenclature" :
Division (Phylum) Genus
Variety Form
Two systems of plant classification are given in Table 2. Some of
the microscopic types of fossil remains of non-vascular plants have:been
discovered. Some of these forms do not yet fit into the classification
scheme because they are only fragmentary remains of an extinct organism
Other forms, because of their morphologic similarity to an extent plant or
plant part, can easily be placed in an appropriate class, family, genus, or
even species, e.g., fresh-water algae from oil shale. Some problematic fossil
algae are Schizocystia, Lecaniella, and Horologinella. Representatives of
most of the thallophyte phyla have been found as fossils, and most of
the phyla have been recognised as microscopic remains in palynological
preparations. The spore known as Tasmanites is of interest because it
occurs abundantly in the coallike or kerogenlike "white coal". Tasmanites
Fundamentals of Palynology
Two Systems of Plant Classification
Fuller and TIppo (1949)
Subkingdom Thallophyta
Phylum Cyanophyta-blue-green algae
Phylum Euglenopyta - euglenoids
Phylum Chlorophyta - green algae
Andrews (1961)
Phylum Chrysophyta - yellow-green ALGAE
algae, golden-brown algae, and diatoms
Phylum Pyrrophyta - cryptomonads
and dinoflagellates
Phylum Phaeophyta - brown algae
Phylum Rhodophyta - red algae
Phylum Schizomycophyta - bacteria
Phylum Myxomycophyta - slime molds
Phylum Eumycophyta - true fungi
Subkingdm Embryophyta
Phylum Bryophyta (or Atracheata)
J ~
Class Musci - mosses Division Briophyta
Class Hepaticae - liverworts ] Division Hepatophyta
Class Anthocerotae - homworts
Phylum Tracheophytal - vascular plants
Subphylum Psilopsida
Class Psilophytineae Division Pripophyta
Order Psilophytales
Order Psilotale.,
Subphylum Lycopsida - clubmosses
Class Lycopodineae Division Lycapodophyta
Order Lycopodiales - clubmosses
Order Selaginellales - small clubmosses
Order Lepidoden-drales
- giant clubmosses
Order pleuromeiales
110 Encyclopaedia of Petroleum Science and Engineering
Order Isoetales - quillworts
Subphylum Sphenopsida - horsetails
Class Eqisetineae
Order Hyeniales
Order Spheno-phyllales
Order Equisetales - horsetails
Subphylum Pteropsida
Class Filicineaeferns
Order Coenopteridales
Order Ophioglos-sales
Order Marattiales
Order Filicales
Class Gymnospennae-
conifers and their allies
Subclass Cycadophytae
Order Cycadofili-
3 - seed
Order Bennettitales
4 j
Order Cycadales-cycads
Subclass Coniferophytae
Order Cordaitales
Order Ginkgoales-
maidenhair tree
Order Coniferales-confiers
Order Gnetales
Class Angiospennae-
flowering plants
Subclass Dicotyledoneae
Subclass Monocotyledoneae
1. Also known as Tracheata.
2. Known only as fossils.
3. Also known as Pteridospermae.
4. Also known as Cycadeoidales.
Division Arthrophyta
Division Pterophyta
Division Cycadophyta
Division Coniferophyta
Division Ginkgophyta
Division Coniferophyta
Division Gnetophyta
Division Anthophyta
Fundamentals of Palynology 111
has an affInity to the algae, based largely on the absence of haptotypic
structures. Coenobia of Pediastrum are not uncommon in palynological
preparations. Pediastrum may be of importance as a facies indicator.
Filamentous algae are rarely found as fossils. Botryococcus is another
alga that is often found in palyndogical assemblages. It has been reported
from rocks at least as old as Ordovician.
Boghead coal is made up largely of an alga similar to Botryococcus.
This alga is living today in fresh-water lakes and brackish-water localities.
An attribute of living Botryococcus is its ability to produce large
quantities of oil. Fossil representatives of the Cyanophyta, Euglenophyta,
and Chlorophyta are occurring in the Green River shales. The phylum
Pyrrophyta, which includes the dinoflagellates, is very well represented
in palynological preparations. The two remaining algal phyla, the
Phaeophyta and Rhodophyta possess plant bodies that are commonly
difficult to preserve. The remaining phyla of the Thallophyta do not
possess chlorophyll and may be considered bacteria and fungi. Bacteria
have been recorded as fossils. Mycelia of the Eumycophyta, or true fungi,
are common accompaniments of palynological assemblages. Spores
similar to the teliospores of rusts are also fairly common. A few other
fungal remains such as Phragmothyrites have been reported. In the
subkingdom Embryophyta only one phylum, the Bryophyta, does not
possess vascular tissues. This phylum includes the mosses, liverworts,
and homworts. It is the only non-vascular phylum that produces thick-
walled spores in tetrads. These spores, when separated from the tetrad,
commonly display a trilete suture. See Fig. 3.
The subphylum Psilopsida embraces two orders, the Psilophytales
and the Psilotales. The Psilophytales are known only as fossils.
Four species of a primitive group of vascular plants were described
from the Rhynie chest of Devonian age and their genera were Rhynia,
Horneophyton, and Asteroxylon. An abundance of trilete spores
was found in the sporangia of Rynia major. The earliest vascular plants
known to possess trilete spores are Baragwanathia from r09ks of Silurian
age in Australia. The Psilotales are represented in the Imodem flora
by the genera Psilotum, with two species, and Tmesipteris, with only a
single species. Two of the five orders belonging in the subphylum
Lycopsida are known only from fossils. They are the Lepidodendrales,
and the Pleuromeiales. The Lepidodendrales were all trees. They appeared
first in the Devonian and persisted to the end of the Carboniferous. These
112 Encyclopaedia of Petroleum Science and Engineering
. ~ ~
:/ r
. ,
Fig. 3, Examples of spores and other structures from nonvascular plants (After
Tschudy and Scott, 1969).
Fundamentals of Palynology 113
plants were among the dominant elements in Carboniferous forests.
The Pleuromeials attained a height of only 2 metres and never were a
dominant part of any flora. The single genus Pleuromeia is known only
from the Triassic. The Lycopodiales, or modern clubmosses, are generally
herbaceous and of worldwide distribution, e.g., from Arctic to temperate
and tropical regions. The order Selaginellales is represented by one
living genus, Selaginella. These small, herbaceous plants are widely
distributed in temperate and tropical localities. The order Isoetales is
represented by two living genera: (1) stylites, and (2) Isoetes. This
Isoetes genus is worldwide in distribution and is found commonly in
shallow lakes or ponds. The Lycopsida may have evolved from the
Psilopsida. The subphylum Sphenopsida contains one class, the
Equisetinese. It consists of three orders: (1) the Hyeniales, (2) the
Sphenophyllales, and (3) the Equisetales. The first two orders are
represented only as fossils. The order Equisetales consists of two families
: (1) fossil germs Calamites, and (2) the living genus Equisetum. Equisetum
possesses spores. Each mature spore is invested with two hygroscopic
elaters that coil and uncoil with changes in humidity. The subphylum
Pteropsida contains all the remaining plants in the plant kingdom. The
class Filicineae is subdividd into four orders. The first of these is
the Coenopteridales, known exclusively as fossils. They apparently
originated in the Devonian and persisted at least through the Permian.
Most of the genera recognised as belonging to the Coenopteridales
are known from stem and petiole anatomy. The Ophioglossales are
the adder's tongue and grape ferns. The Marattiales possess some
characters indicating a more advanced phylogenetic position.
The Marattiales are homosporous and produce both the trilete and
monolete types of spores. The Filicales is a large group containing
about 132 genera. Both the monolete and trilete spore types are found in
this order. All the families of the Filicales are homosporous except
the Marsiliaceae and the Salviniaceae. Both of these families are called
water ferms. Members of these families had already developed atleast
by Cretaceous time and have persisted to the present. The members
of the class Gymnospermae, or conifers and their allies, are
all heterosporous. See Fig. 4. The subclass Cycadophytae contains
the orders Cycadofilicales and Bennettitales, known only as fossils.
The Cycadofilicales, or seed ferns, may have originated in the late
Devonian, attained their acme of development in the Carboniferous, and
114 Encyclopaedia of Petroleum Science and Engineering
~ A
~ " . ' " W"

Fig, 4. Examples of spores from the phylum Tracheophyta
(After Tschudy and Scott, 1969).
some may have persisted into the Cretaceous. The Bennettitales became
extremely abundant in the Jurassic and probably became extinct in the
The modem representative of the Cycadales are mostly limited to
the tropics and subtropics. The pollen is consistently of the mono sulcate
type. The Cordaitales, an extinct order, is perhaps the oldest of several
orders of the subclass Coniferophytae. The order Ginkagoales, once
widespread and made up of many genera, is now represented by only
Fundamentals of Palynology 115
one genus and species, Ginkgo biloba. The order Coniferales is
represented by such well-known plants as pine, fIr, juniper, and spruce.
The plants in this group fIrst appeared in the Pennian and were dominant
in Jurassic and Triassic times. The Genetales, the most advanced order
of the subclass Coniferophytae, is represented at the present time by
the three genera: (1) Welwitschia; (2) Gnetum; and (3) Ephedra. The class
Angiospermae, or flowering plants, is divided into the subclasses
Dicotyledoneae and Monocotyledoneae. The pollen and spore types
known from the orders are given in Table 3.
Cycles of Plant Life
The life cycles of plants typically consist of two stages, a
gametophyte generation with a single complement of chromosomes (n)
and a sporophyte generation with a double complement (2n). An
examination of the life cycles of a few plants demonstrate the evolutionary
trends from simple life form to the most complex i.e., the attgiosperms.
See Fig. 5. The gametophyte generation in most lower plants is physically
the larger plant of the two generations. In some algae the sporophyte
generation is represented by a single cell, the zygote, e.g., spirogyra.
When growth of the zygote begins reduction division takes
place immediately, and the gametophyte generation reappears. The
converse is true in the angiosperms in which the gametophyte generation
is confmed to the pollen-grain tube and to the few cells of the female
gametophyte, hidden in the ovule enclosed in an ovary. The larger
plant is the sporophyte. Pollen grains have evolved from spores. The
spore has a nucleus that has undergone reduction division in the
formation of the spore. The spore represents the beginning of the
gametophyte generation and on germination and growth produces the
gametophyte generation. In some heterosporous genera the female
gametophyte develops within the spore coat. In both the gymnosperms
and the angiosperms the magagametophyte is entirely enclosed within
the tissues of the sporophyte. Pollen grains differ from spores is being
multinucleate young male gametophytes, whereas spores are uninucleate
and develop into gametophytes outside the spore coat. Pollen is
commonly different in external form. But it is essentially a spore in which
development of a male gametophyte has proceeded before liberation from
the sporangium.
116 Encyclopaedia of Petroleum Science and Engineering
Spore and Pollen 1YJ1es in the Bryophyta and Tracheophyta
Spore or Homosporous or
Plant Group Pollen TYpe Heterosporous
Bryophyta Trilete, Homosporous
Psilophytales Trilete, Homosporous
Psilotales Monolete, trilete Homosporous
Lycopodiales Trilete Homosporous
SelagineIIaIes Trilete Heterosporous
Lepidodendrales Trilete Heterosporous
Pleuromeiales Trilete Heterosporous
Isoetales Monolete, trilete Heterosporous
Hyeniales Trilete? Homosporous
SphenophyIIales Trilete? Homosporous,
Equisetales Trilete, Homosporous,
inaperturate heterosporous
CoenopteridaIes Trilete Homosporous,
Ophioglossales Trilete Homosporous
Marattiales Monolete, trilete Homosporous
FiIicaIes Monolete, trilete Homosporous,
Cycadofilicales Trilete, monolete, Heterosporous
Bennettitales Monosulcate Heterosporous
Cycadales MonosuIcate Heterosporous
Cordaitales MonosuIcate Heterosporous
Ginkgoales Monosulcate Heterosporous
Coniferales Monosulcate, Heterosporous
Gnetales MonosuIcatc. Heterosporous
Angiospermae Various Heterosporous
Fundamentals of Palynology
Fig. 5. Diagrammatic life cycles of Anthoceros, a generalized fern, SeIaginella, a
gymnosperm; and an angiosperm (After Tschudy and Scott, 1969).
118 Encyclopaedia of Petroleum Science and Engineering
The megagametophyte produces eggs. One of these is fertilized by
a sperm nucleus brought into the female gametophyte in the pollen tube.
The fertilized egg develops into a young sporophyte within the tissues
of the ovule. A seed consists of sporophytic tissue, the integuments,
the nucellus, the endosperm, the megagametophyte and the young
sporophyte or embryo. The endosperm develops from the fusion of one
sperm nucleus and the fused polar nuclei. Commonly the young embryo,
by the time the seed is mature, has taken up all the food material originally
present within the nucellus and endosperm. Consequently such a seed
then consists of the young embryo and only remnants of the
megagametophyte, nucellus, and endosperm, all enclosed in the ovule
integuments. The male gametophyte within the pollen grain of
angiosperms is reduced to three nuclei : the tube nucleus and the two
sperm nuclei.
Devonian Spores
Spores occur in both marine and continental strata. Acritarchs are
known from the Precambrian and occur abundantly in Lower Paleozoic
marine strata. Continental strata are practically absent from the geological
column before Late Silurian - Early Devonian time, and trilete spores are
most abundant in continental and marginal marine strata. The spores
found are mainly azonate, smooth and retusoid. Sculptured forms
are much more rare. but they occur in an increasing variety from the
Wenlock to the Ludlovian. Compared with records of bonafide trilete
spores from Silurian rocks, the lower Gedinnian assemblages represent a
considerable increase in the number of spore types. Considering
Gedinnian assemblages as a whole, we fmd several distinct features that
separate them from succeeding Devonian assemblages. Firstly, the spores
are very small. Secondly, well-developed contact areas and curvaturae
perfectae are a constant feature. Sculpture is varied compared with
Silurian forms, i.e., granulate, apiculate, spinose, individually biform,
verrucate, murinate and reticulate patterns are all developed, but many
of these sculptured spores have smooth proximal faces. Another proximal
development of importance is the presence of proximal radial ribs. See
Fig. 6. Descriptions of welldated Siegenian and Emsian assemblages are
rare, but the few that are available indicate a similar pattern of
development. A striking feature is the early appearance of important
Fundamentals of Palynology 119
Devonian genera, many of which had appeared by the upper Ernsian.
See Fig. 7. Spores assemblages from these strata tend to be larger in size
and continue to have proximal differentiation although not of the extreme
type shown in the Gedinnian. The proximal ribs are often more thickened,
and robust, and these forms are clearly differentiated as a distinct group
of spores. Emphanisporites with well-developed annulate distal
thickenings occurs in possible Siegenian strata and continues into Middle
Devonian and lower Upper Devonian strata. Pseudosaccate and zonate
smooth and sculptured types are also present. Records of pre-Middle
Devonian types with anchor-shaped spines are rare. Spores of the
megaspore size range occur in the Siegenian. See Fig. 8. Middle Devonian
strata contain large pseudosaccate and zonate forms frequently with
prominent sculpture which is of various types although often spinoze.
Spores with well-developed bifurcate spines are varied and frequently
abundant. Geminospora forms have a thick outer wall and a thin inner
body separated by a cavity. Frasnian assemblage are frequently
characterised by monolete spores of the genus Archaeoperisaccus. See
Fig. 9. Famennian and Lower Carboniferous assemblages illustrate the
widespread occurrence of some of the spore species, e.g.,
"Hymenozonotriletes" lepidophytus. Forms with bifurcate spines are still
present and may be prominent in certain lithofacies but appear to die
out rapidly in the Lower Carboniferous. Pseudosaccate spores with
prominent pointed spines are also commonly present. With regard to size,
small and large spore species have distinct size ranges. Famennian and
lowermost Carboniferous spore assemblages are closely similar and tend
to differ considerable from Frasnian assemblages. Frasnian assemblages
are much more comparable with the Givetian.
Devonian Spores (Biological Significance)
There is ample evidence that the early vascular land plants
produced trilete spores similar to those found dispersed in sedimentary
strata. Trilete spores are clearly preset in the Silurian, but the few
so far recorded as predominately simple smooth types possibly belonging
to six genera. Through the Lower Devonian there is a rapid increase in
the number and in the morphological diversity of the spore genera,
which perhaps reflects rapid colonization by vascular plants of the newly
120 Encyclopaedia of Petroleum Science and Engineering
Fig. 6. Upper Silurian and Lower Devonian Spores.
Fundamentals of Palynology
'" 3::
'" ;;
'" :;;
_0 ________ . ____ ... ... __ ....... __ .. _ __ .. __ .. _ ..
"' ...
Fig. 7. Range chart to show the knoWn distribution of Devonian spore genera
(After Tschudy and Scott, 1969).
122 Encyclopaedia of Petroleum Science and Engineering
Fig. 8. Lower Devonian Spores-"Dittonian".
Fundamentals of Palynology 123
Fig. 9. Middle and Upper Devonian Spores-Eife1ian, Givetian, and Frasnian
(After Tschudy and Scott, 1969).
124 Encyclopaedia of Petroleum Science and Engineering
fonned Devonian landmasses. The Gedinnian appears to have been a
time of gradual change of the land flora, followed by more rapid
diversification in the Siegenian and Ernsian. In morphology, genera
present, and size that appear to be quite distinct from later Early Devonian
spore floras, which suggests that they parallel rnacrofloral changes. A
further period of change appears to have taken place at the beginning of
the Famennian with, on the whole, very little difference between the late
Famennian and early Tournaisian (Early Carboniferous), and finally a
further floristic change is indicated by the introduction of several
important Carboniferous spore genera in the late Toumaisian. The
evidence from fossil trilete spores indicates little pre-Devonian
diversification of the land flora, than fairly rapid diversification and
development in the Early Devonian, especially in the latter part of this
time, followed by the gradual introduction of new types through the
Middle and Late Devonian. There is no such threefold breakdown of the
plant microfossils. Land plants spread widely in the Lower Devonian and
rapidly became diverse, that there is no simple threefold floristic division
in the Devonian.
The small size of the Gedinnain spores and the modal size peak would
suggest that the plants producing them were homosporous. Spores
frequently have thin proximal walls, which suggests that most of the
spore development took place in the tetrad and little or none after
separation. Further the relatively unifonn basic morphology of the spores
does not suggest great differentiation among their parent plants. The
Gedinnian assemblages is the presence of prominent proximal papillae in
several of the spores. This is a character seen in spores of some
Carboniferous lycopods. The plant genus Asteroxylon from the Rhynie
chest possibly a lycopod or close to the lycopod line of development.
Re.tusotriletes triangulatus occurs in Lower and Middle Devonian strata.
The microspores of Barinophyton richardsoni are similar to those from
Dawsonites in that they have a thickened apical area and a "perisporal"
membrane. Siegenian spore assemblages show greater variety of spore
types than those described from the Gedinnian. The Middle Devonian
saw an increase of spore size, with many spores grading into the
megaspore size range and several spore species with a size mode of over
200 microns. Much less is known of the affinities of spores with bifurcate
Fundamentals of Palynology 125
processes, which are also widely dispersed and frequently abundant in
the Middle and Upper Devonian. A further interusting spore-plant
association involving a spore type occurring in the Middle and Upper
Devonian is that between the dispersed-spore genus Biharisporites and
the important Devonian plant genus Archaeopteris. The spores of
Archaeopteris, Aneurophyton, and Svalbardia are also structurally similar
in possessing a thick outer layer and a thin inner layer. The spore genera
Geminospora and Rhabdosporites are widely distributed and often
abundant in upper Eifelian, Givetian, and Frasnian assemblages. Spores
have potentially a much greater palaeobotanical role as indicators of the
distribution, evolution and relationships of their parent plants because
spores are much more abundant then identifiable large plants remains.
The uniformly small size of Silurian and Gedinnian spores suggests that
the plants producing them were all homosporous. In the Siegenian and
Emsian the size range of spore types is much greater. There is some
indication that heterospory may have developed at this time. In the
Middle Devonian the spore evidence for heterospory is stronger. Detailed
studies of spore assemblages, especially those from well-controlled
stratigraphic Sequences, can be expected to throw a great deal of light
on the evolution and geographic distribution of Devonian spores. Such
studies are a valuable tool for the determination of age, especially in
continental sediments, they also have an immense potential as indicators
of plant relationships, the course of evolution, distribution, and habitat
of the earliest land flora.
Devonian Spores (Geographic Distribution and Facies Relationships)
Many spore assemblages are described from strata of comparable
age which are closely similar from various parts of the world (Richardson,
1965a). However, differences are also apparent; some of these differences
may be related to broad geographic control (floral provinces), whereas
others appear to be more closely linked to lithofacies and depositional
environment. The latter may partly be due to proximity to the site of
growth of parent plants as well as mechanical sorting and preservation
factors. Strata from the Middle Old Red Sandstone of the Orcadian basin,
Scotland, are believed to have formed in a relatively large body of fresh
water. Spore assemblages from the Orca dian strata are frequently
dominated by two spore types: (1) Ancyrospora, and (2) Rhabdosporites
126 Encyclopaedia of Petroleum Science and Engineering
langi. These two genera frequently constitutes as much as 50 percent of
the assemblage. Specimens of Ancyrospora are especially abundant and
in some beds make up 20 to 50 percent of the total spore control. Spore
assemblages from comparable horizons in the Soviet Union have many
species in common with the Scottish assemblages but somewhat different
from them. Firstly, Ancyrospora is present but not abundant; on the other
hand, thick-walled spores referable to the genus Gerninospora are
relatively common (Kedo, 1955). These differences are related to plant
ecology, with Gerninospora-producing plants living in marginal deltaic
or coastal flood-plain areas, whereas plants living in or around fresh-
water lagoons were shedding spores of Ancyrospora and
Rhabdosporites. In New York State a similar relationship exists in the
Frasnian. Here fresh-water massive grey sandstones-siltstones contain
abundant Ancyrospora, Hystricosporits, and Rhabdosporites. In contrast,
Geminospora occurs abundantly in association with red, and variegated
red and green, silts and sandstones oflower flood-plain-marginal deltaic
facies. Spore assemblages of Fransnian age have been described from
the Escuminac Formation of eastern Canada. These assemblages closely
resemble those from the Scottish Middle Old Red Sandstone in gross
morphological aspect. Spore assemblages from this formation contain
abundant spores like Ancyrospora and Hystricosporites and also similar
to Rhabdosporites langi. Thus it would seen that in eastern North America
we have a situation similar to that in Western Europe, with the abundance
of certain spore forms occurring in association with distinctive type of
facies. Naumova (1953) also comments on the variability of spores
assemblages of Frasnian age and attributes this variation to transgression
and regression of Devonian seas. Comparison of spore assemblages in
different facies suggests that there is some evidence for ecological
differentiation of Devonian plants. Another interesting example of
apparently restricted spore distribution is that of the dispersed-spore
genera Archaeoperisaccus and Nikitinsporites. There is clear similarity
of some species of Archaeoperisaccus to the micro-spores of
Krystofovichia africani. Several horizons containing Archaeoperisaccus
also contain large spores of the genus Nikitinsporites, which resemble
the distinctive Krystofovichia megaspores. Outside the Soviet Union
these two genera have only been recorded together from arctic and north-
Fundamentals of Palynology 127
western Canada. Arctic Canada shows monolete grains intimately
associated with the apical area of spores of Nikitinsporites. It would be
particularly interesting to find the parent plant of these spores, which
apparently have such a restricted stratigraphic and geographic
distribution. It will also be interesting to see whether arctic and northwest
Canadian spore assemblages differ in other ways from those in the
southeastern parts of the North American continent and to study factors
that may relate to these differences.
Dinoflagellates and other Organisms in Palynological Preparations
Besides spores, pollen and fmely comminuted fragments of plant
tissues, palynological preparations often contain notable amounts
of other microfossils of organic compositions. These include
morphologically diverse objects of varied natural affmities. Most of them
represent aquatic organisms that lived in waters ranging from fresh to
open marine. These fossils are an important complement to those
derived from land plants, which often occur in the same samples. Most
studies have utilized isolated specimens recovered by acid treatment and
prepared fmally as either single-specimen mounts or strew preparations,
each type having its special advocates and advantages. Operculate
openings in many fossil dinoflagellates and some acritarchs have
been widely referred to as pylomes. The term archeopyle is applied to
openings whose shape or position (commonly both) may be correlated
with the arrangement of plates in a dinoflagellate theca. Most archeopyles
are operculate and basically polygonal, but they may also be slitlike
and of irregular shape. Archeopyles have now been observed in resting
cysts of modem species. The term pylome is reserved for openings
among acritarchs. They are most often approximately circular and
operculate, more rarely polygonal or slitlike, and cannot be clearly
corrrelated with a pattern of plate arrangement as in dinoflagellates. There
has been much experimentation to determine the composition of the
organic remains of dinoflagellates, acritarchs, and chitinozoans, but the
exact nature of the compounds involved remains obscure. Significant
observations are the cutinoid composition of some acritarchs and the
variable silica content in some dinoflagellates has been reported. The
somewhat varied and generally undemlined composition of the fossils
today reflects an unknown postdepositional modification of unknown
original organic compounds. Dinoflagellates with siliceous or calcareous
128 Encyclopaedia of Petroleum Science and Engineering
external tests have been described. In adddition stellate siliceous
structures like those that occur within Actiniscus, a modem unarmored
dinoflagellate, are frequently encountered in Tertiary diatomites and were
given the name Actiniscus. These fossil dinoflagellates with fully
mineralized remains are not common constituents of palynological
Dinoflagellates (Basic)
The fossil record of dinoflagellates extends from Silurian to Recent,
but a single Silurian occurrence is the only pre-Permian one yet reported,
and specimens are rare before the Middle Jurassic. Beginning then
dinoflagellates are common constituents of marine assemblages, although
fossil freshwater dinoflagellates are rare. The tests are morphologically
diverse and reasonably complex. They are thought to be cysts rather
then the thecae of organisms in the actively swimming stage. Although
many of the fossils do resemble thecae, others are of quite different
aspect, and intermediate types occurs. Characterization of genera and
species is on the basis of shape, number, and position of major projections
or lesser projections, character of a distinctive opening through which
the contents escaped, wall structure, and a variety of features that reflect
the plate pattern of the now-vanished theca. Local and cosmopolitan
species occur. Extensive geographic ranges combined with rapid
evolutionary changes, render many types excellent tools for long-range
correlation as well as for local zonation.
Dinoflagellates are unicellular aquatic organisms generally treated
as a class within the division Pyrrhophyta among the algae. They
commonly range from about 10 to 100 microns in size, with occasional
giants upto 1.5 millimetres. The majority are free-living elements of the
oceanic plankton; but the group also includes bottom dwellers as well
as symbiotic and parasitic types, and their habitat extends to brackish
estuaries and freshwater rivers, lakes, and ponds. Some of the free-living
dinoflagellates are heterotrophic, but the majority are autotrophic.
Characteristic pigments are chlorophylls a and c, beta-carotene, and four
Xanthophylls. An identical combination of chlorophylls and beta-
carotene occurs in the brown algae. Diagnostic of dinoflagellates is an
, actively swimming, or motile, stage during which the cell is propelled by
two flagella, one extended longitudinally and the other encircling the
longitudinal axis. See Fig. 10. The forward movement of the cell is often
combined with a distinctive spinal motion. In almost all cases
Fundamentals of Palynology
- Flagellum
L ...........
-- ...... tum
(,l flJ
Fig. 10. Examples of Recent dinoflagellates (After Tschudy and Scott, 1969).
eprodu ctive appears to be exclusively of the vegetative type involving
either a single or multiple division that results in two or more daughter
cells, each capable of developing to maturity. Dinoflagellates of many
types are naked cells in the motile stage, but in two large groups the
motile cell is enclosed in a theca consisting chiefly of cellulose. In one
of these groups (Dinophysidales) the theca has a sagittal suture and
comes apart into two roughly symmetrical halves. In the other group
130 Encyclopaedia of Petroleum Science and Engineering
(Peridiniales) the theca consists of a number of polygonal plates arranged
in several latitudinal series. The number and arrangement of the thecal
plates differ among texa and can be described by standard terms and
symbols. See Fig. 11. Armored dinoflagellates exhibit a great variety of
outline shapes with nearly circular to elliptical shapes dominating. A
single apical horn and one or two antapical horns are common.
Dinophysis represents the exclusively marine Dinophysidales. The other
three genera are Peridinium, Ceratium, and Gonyaulax. They represent
the Peridiniales and are abundantly represented today by both freshwater
and marine species. Many Peridinium species are nearly bilaterally
symmetrical, and a prominent group of anterior intercalary plates in
median position is characteristic. Gonyaulax exhibits a strongly
asymmetrical plate arrangement. Ceratium species characteristically
________ Apical pore
-- __ Apical plates Apex
2' Anterior Intercalary plates
Fig. II. Dinoflagellate tenninology and tabulation.
Fundamentals of Palynology 131
possess conspicuous horns, including one antapical hom and one that
rises from the postcingular region. Many living dinoflagellates exhibit it
large intraspecific variability in thecal shape, e.g., Ceratium fusus and
Citripos. Dinoflagellates are small but fundamentally important organisms
in the sea today where, together with the diatoms, they are the basic link
of the food chain. Dinoflagellates are most varied and abundant in modem
tropical seas.
Many dinoflagellates pass through an encysted stage in addition
to the mobile stage. Dinoflagellate fossils appear to be remains of cysts,
rather than of once-mobile thecae. Depending on the species and the
circumstances, cyst formation in modem dinoflagellates apparently may
be associated with four conditions : (1) the onset of unfavourable
environmental conditions, (2) a resting period in the life cycle, (3) a part
of the reproductive phase, and (4) a period of "digestion" of solid food.
The resting cysts may be simply spherical, with or without spines. Among
the small number of modem resting cysts two are important: (1) the cyst
of Gonyaulax digitalis, and (2) the cyst ofPeridinium leonis. The walls of
these cysts are chemically more resistant than thecae, and they possess
excystment apertures comparable to the openings known in many fossil
dinoflagellates. See Fig. 12. The shape and size of cysts in Ceratium vary
much less than do the thecae of the mobile stage. The horns characteristic
of the Ceratium theca are noticeably abbreviated if present in the cyst,
and the cingulum, prominent in the theca, is not discernible in the cyst.
Dinoflagellates (Fossil)
Dinoflagellates are represented by fossils that vary between wide
Fig. 12. Diagrammatic sections of Recent dinoflagellate cysts inside thecae.
132 Encyclopaedia of Petroleum Science and Engineering
. extremes in morphology. See Fig. 13. Some of the hystrichospheres were
dinoflagellate cysts formed within thecae that have subsequently
disintegrated or disappeared. A thecate dinoflagellate in the actively
swimming stage begins to encyst. The flagella are cast off and the cell
content contracts, forming about itself a thin covering of chemically
resistant organic material. The plates of the less resistant theca dissociate
or disintegrate. Eventual excystment is accomplished by rupture of the
cyst wallalong defInite lines or by general dissolution of the wall. The
"" .
~ :. 4' ' , , ~
..... -', ':
- . ~ ' ~ "
Fig. 13. A spectrum offossil dinoflagellates.
Fundamentals of Palynology 133
fidelity with which a fossil dinoflagellate cyst reveals the features of the
theca and therefore the extent to which the fossil is "dinoflagellate-like"
in appearance depends partly on the proximity of the main surface of the
cyst to the theca. Fossil can be recognized as a dinoflagellate by three
criteria: (1) Flagellar furrows, (2) tabulation, and (3) shape. Flagellar
furrows alone are conclusively diagnostic of dinoflagellate affinity if they
can be reliably identified, e.g., Dinogynmium. Tabulation is the pattern
of plate arrangement in a dinoflagellate theca. A very important indication
of tabulation is the archeopyle. A distinct archeopyle of identifiable type
is sufficient by itself to establish the dinoflagellate nature of an unknown
fossil. The overall shape of dinoflagellates ranges through gradational
stages from nearly spherical to conspicuously three-pointed, with many
variations along the way. Horns are major projections of the test. They
seldom number more than five and appear to be abbreviated versions of
major projections that characterize thecae of many modem dinoflagellates.
See Fig. 14. In contrast to horns, processes and speta seen not to
Fig. 14. Horns in fossil dinoflagellates.
represent structures that projected from the theca but to be unique
features of the cyst that formed within the theca. The prominence of
processes or septa depends on the ratio of the diameter of the main body
to the total diameter of the cyst. The form and arrangement of the
projecting structures are important taxonic features. See Fig. 15. Their
distribution is tabular if it reveals the pattern of thecal tabulation, non-
tabular if it does not. Processes may be solid or hollow, open or closed
at their tips or bases, in substance fibrous or hyaline. A single specimen
may exhibit one or more styles of projecting structure. In many but not
all hystrichospheres within processes in intartabular arrangement it is
possible to recognize which thecal plate is reflected by each process, or
process group and .thus to determine the formula of the complete thecal
tabulation. The archeopyle is the excystment aperture in the resistant
wall of a dinoflagellate resting cyst. See Fig. 16. Its shape and position
are closely related to a pattern of thecal tabulation. The shape and
position of the archeopyle generally suffice to identify the thecal plates
that are reflected by the portion of the test wall involved in its formation.
134 Encyclopaedia of Petroleum Science and Engineering
Processes .nd
1-// Sutural
, ,
~ "" .... <- _1 A ....
. .
.. .
.. ~
"'1\- - -.0- '-.<:\- '. J;\
/.{" -<:\ ll. ~ 11
-\..i... 4 . ) ~ - -
A " . ~ _ 41 Ii c.
t:I -- ./J - ->q/ 1\
r-. -<l ;,;-:.n ....
Fig. 15. Surface features of fossil dinoflagellates (After Tschudy and Scott, 1969.
In some species an archeopyle has never been observed; in others it is
consistently present, in still other species the operculum is in place in
some specimens and missing from others. Opercula found separated from
the rest of the test can often be identified with the species they represent
on the basis of details of surface structures, processes, size, or shape.
A tendency toward bilateral symmetry is recognizable in most
species, even when shape or projecting structures suggest a radial or
axial symmetry at first glance. The walls of fossil dinoflagellates are as
Fundamentals of Palynology 135
An::heopv1e Types
2A" 6P
Fig. 16. Archeopyle types in fossil dinoflagellates.
varied as other features of their morphology. The majority of fossil
dinoflagellates have two walls, but among the minority are to be found
cyst with one, three, or four walls. See Fig. 17. Tests with a single wall
only are autoblasts, with an autopbragm enclosing the autocoel. In the
(hJ LJe/lulidrea
- - - - -
~ - -
() Hvs",chusp"aera
~ '
(dJ Wn:eildlu
(,I PseudocrrQtlllm
Fig. 17. Wall structure in fossil dinoflagellates.
136 Encyclopaedia of Petroleum Science and Engineering
more common, two-walled cysts an endoblast, consisting of the
endophragm about the endocoel, is itself surrounded by an outer
wall, or periphragm. The presence of more than two walls is unusual.
The archeopyle, if present, is usually the only opening in the
endophragm or autophragm, but many additional openings may occur in
the periphragm, as at the tips of certain hollow processes or along the
horns of Odontochitina. Major differences in shape, presence or absence
of a distinct inner body, and details of tabulation are the characters
that have been most commonly used to distinguish general of obvious
dinoflagellates. The distinct general of fossils that have been recognized
on the basis of cyst structures other than reflected tabulation would
be greatly reduced in number if thecal tabulation instead were the chief
basis for separation. There are two classes, the Dinophyceae, or
dinoflagellates, and the Desmokontae. The Desmokontae comprise free-
swimming cells with two nearly equal flagella at the apex of the cell. They
are naked or have a two-valued cellulose envelope with a sagittal suture,
e.g., Prorocentrum and Exuviella. Dinophyceae with a theca of two
symmetrical values joined along a sagittal suture. Furrow margined by
ridges, crests or erect membranes. Girdle far forward in most genera, often
Occurrences of fossil dinoflagellates before the mid-Jurassic are rare.
Beginning with the Middle Jurassic, dinoflagellates are conspicuous
elements of many marine assemblages. Upper Jurassic and younger
deposits contain a vast array of forms only in part referable to the 200 or
so genera described until now. Some dinoflagellates are good horizon
makers and highly useful tools for zonation and correlation over both
short and long distances.
Early Paleozoic Palynomorphs
The relationships of some of the named rock units, time units, and
fossil zones of the early Paleozoic are shown in Fig. 18. In 1949 Naumova
reported abundant spore like microfossils from the Lower Cambrian Blue
Clay of the Baltic region. In 1950 she reported on palynomorphs of her
Lower Silurian ranging from Tremado to lower Caradoc in the same region.
Tirnofeyev (1959) has enlarged on Naumova's observations. Apparently
most of the Cambrian and Ordovician argillaceous deposits in this region
provide abundant microfossils in a favourable state of preservation. One
of the greatest contrasts in the invertebrate faunas occurs between richly
fossiliferous Ordovician deposits and the generally much less
Fundamentals of Palynology




- --



:;)"l! Caradoc
Festimog (Olelus)
lewistoni.n ----'I;M;;-ed:::;;:ina=--L....J-O----;l-=o=we-:r:-1

Maysville 0.0
Mohawk,an - 1-__ __ -lr--?-

___ ______ -

1 J :: .. --
Canadian .. , ...... 0';--- -
r 1---....: ..... ;=-=---

--------- ---
------- --
Croixlan f Dunde,be"uz)
_--L ______ _

:;) ..

:;; ..
Fig. 18. Stratigraphic units used for lower Paleozoic systems in Europe and
North America (After Tschudy and Scott, 1969).
fossiliferous beds of Cambrian age. Diversification of the plant-microfossil
assemblages anticipates this faunal change. Fig. 19 shows the more
common and simple types that occur in both the Proterozoic and
Cambrian. Simple sporelike forms, commonly adpressed in irregular
groups, occur in deposits as young as Ordovician. Microfossils of quite
a different and more distinctive type, many of which are bilaterally
138 Encyclopaedia of Petroleum Science and Engineering
crj 0
Fig. 19. Acritarches from upper Precambrian and lower Paleozoic deposits
(After Timofeyeu, 1959).
Fundamentals of Palynology 139
symmetrical, occur in the Ischorian (Middle Cambrian) beds and above.
See Fig. 20. The spheroidal types (35 to 45), no doubt are acritarchs or
i: ;

-.. " ~ 9
Fig. 20. Diacrodioid palynomorphs and acritarchs.
140 Encyclopaedia of Petroleum Science and Engineering
"hystrichs" that are widely distributed in the middle as well as lower
Paleozoic. The bilateral symmetry shown by SOIne' of the sporelike
microfossils of early Paleozoic assemblages is a most striking indication
of floristic differentiation. The diacrodioid fossils commonly are
compressed to form two accurate folds, which must be prominent
microscopic features. A defInite gametophytic polarity with a functional
trilete suture would be a more reliable indication of the existence ofland
plants. The palynomorphs of the early and middle Paleozoic have usually
been reported as hystrichosphaerids or as acritarchs. Acritarchs offer
perplexing taxonomical problems. The most fundamental question
concerning these microfossils relates in evaluation of the degree of
polyphyleticism within the group. No doubt a great deal of the similarity
of appearance reflects a universal biologic application of principles
governing size and form and dissemination. For purposes 9ftexonomic
assignment it may be necessary to emphasize and attach more signillcance
to incidental features and minor resemblances than seems, on casual
inspection, reasonable. Morphologic terminology may be used either in
the sense of functional analogy or in the sense of homology. It seems
doubtful that these supragenetic taxa can be regarded as having formal
states in taxonomy because an all-important functional biologic
justifIcation appears to be lacking for each of them. They represent
arbitrary groups of genera. The group proposed can probably provide a
useful artifIcial basis for identifIcation. Illustrations of specimens assigned
to various genera that exemplify these morphologic groups are shows in
Fig. 21. The authors who proposed these groupings of acritarchs agree
that many of the rather similar microfossils in Mesozoic and Tertiary
deposits are referable to the Dinophyceae. The abundant bilateral types
of acritarchs that characterize Middle and Upper Cambrian and Tremadoc
appear to be much diminised or lacking in younger deposits. Simple, thin-
walled, spheroidal types, known as leiospheres, become abundant in the
Upper Ordovician, Silurian, and Devonian. The smooth-walled acritarchs
with a few hollow, elongate appendages have been studied by Downie
(1963) from the Wenlock Shale. See Fig. 22. Downie reported a more or
less progressive change in the acritarch populations throughout the
Wenlock sequence. A fIrst attempt at derming stratigraphic distribution
of acritarch general was provided by Eisenach (1963a), who simply listed
Tasmanites was defIned and named by Newton in 1875. Characteristic
disseminules of the type species make up a large proportion of the marine
Fundamentals of Palynology 141
\ ...
;, ':
~ ~ .-.
- ~ . ~ .. -...... - ~
Fig. 21. Acritarch microfossils, representative of morphologic groups (After
Tschudy and Scott, \969).
black shale of Permian age in the Mersey Valley of Tasmania. Solid
deposits of the Tasmanites disseminules from Alaska have been reported.
Recognition of Tasmanites as a planktonic alga suggests that such pure
tasmanite deposits accumulated from algal blooms. The fossil
disseminules of Tasmanites is as cysts of members of the class
Prasinophyceae. Pachysphaera cysts develop from motile swarmers and
may be as small as 10 microns in diameter. The great range of size in
Tasmanites, as in the cysts of Pachysphaera, is a result of ontogeny and
normal growth. Differences in micellar organization may make the cysts
ofTasmanites more anisotropic than spores of higher plants when viewed
by means of polarized light. Some microfossils assemblages include an
abundance ofTasmanites cysts that are split into two lenticular segments.
The time range of the Tasmanaceae is Ordovician and younger according
to Downie and Sarjeant (1967). Phyletic antiquity implies a corresponding
genetic isolation. Fossil evidence seems to support the identification of
these plants as a separate class of green algae.
142 Encyclopaedia of Petroleum Science and Engineering
2 ~ (
,::.. ':,,"
'r":; J
)( "
~ ~ 8 ~ .
Fig. 22. Silurian and Devonian acritarchs (After Tschudy and Scott, 1969).
Fossil Plant (Angiosperm History)
Angiospenns have dominated the land flora of the earth since mid-
Cretaceous time. The angiosperm-fossil record, which consists mostly
of leaves, is the most extensive from the standpoint of numbers of
specimens of any vascular-plant group. The oldest known plants that
can reasonably be called angiospenns are Sanmiguelia, the palmlike plant
from the Late Triassic, and Furcula, from the Rhaetic. The remains
consists only of leaf impressions and a few fragmentary stem
Fundamentals of Palynology 143
casts, though some cuticle is retained in Furcula. Angiosperms did
undergo remarkable spread and diversity during Cretaceous time. 40
families appeared in the Dakota Sandstone flora of the early Late
Cretaceous. Flowering plants had evolved rapidly during the Early
Cretaceous interval. At least 80 percent of the living angiosperm
families have fossil records of sorts. A considerable number are limited
to remains in Pleistocene peat deposits, but more than half of the
extant families have Tertiary records, and a considerable member can
be traced into the Cretaceous. Leaf impressions and silicified trunks of
palms occur in a number of Upper Cretaceous localities. The list of
angiosperm families is continually expanding as investigations on cuticles
and pollen are completed and published, and as old collections are
reexamined and analyzed by modern techniques. For additional
information consult Engler (1964). Partial list of Cretaceous Angiosperm
Families is give below:
Palmae Ericaceae Meliaceae Rosaceae
Aceraceae Fagaceae Menispermaceae Salicaceae
Annonaceae Guttiferae Moraceae Sapindaceae
Araliaceae Hamamelidaceae Myricaceae Starculiaceae
Betulaceae Icacinaceae Nyrnphaeaceae Tiliaceae
Celastraceae Lauraceae Oleaceae Ulmaceae
Cercidiphyllaceae Leguminosae Plantanaceae Vitaceae
Comaceae Magnoliaceae Proteaceae
Fossil Plant Record
Fossil plants occur mostly in sedimentary rocks. Marine deposits
may contain algae and other forms of sea life, but terrestrial vegetation
is preserved in greatest abundance in sediments laid down under non-
marine conditions. Wherever coal seams occur fossil plants are likely to
be found. Volcanic activity provides ideal condItions for preservation of
plants in large numbers. Lava flows dam streams and form fresh-water
lakes that quickly become filled with erosion products of loosely
consolidated ash deposits. Man of the best known Tertiary floras were
preserved under such circumstances, e.g., Florissant in Colorado. All
parts of the plant body may be preserved as fossils, but they are usually
disconnected from each other, e.g., leaves, pollen, seeds, or stems. The
organs preserved in the greatest quantities are made up of tissues with
144 Encyclopaedia of Petroleum Science and Engineering
the greatest resistance to decay or abrasion, e.g., woody tissues, hard
nuts, seeds, cutinized parts such as spores, pollen grains, and leaves of
coriaceous texture. Plants are fossilized in several ways. The most familiar
types are impressions, which are merely imprints left in soft sediments.
In compressions or compactions the plant parts are squeezed flat between
layers of compacted sediments but under conditions that arrest
decay. In casts a cavity left by decay of a plant part is secondarily filled.
In petrifications some or all the tissue structure is retained by infiltration
with various minerals. The process of petrification is responsible for
the preservation of countless tree trunks found in many parts of
the world, ranging in age from the Devonian to the Recent. Coal
balls, carbonate, and pyritic nodular masses sometimes found in coal
seams or roof shales. Petrifications are of special value in paleobotanical
research because they supply information not revealed in other types of
fossils on the internal structure of extinct plants. Changes do take place
in the chemical composition of plants during petrification. Analyses of
petrified wood have revealed the persistence of cellulose and lignin,
though in proportions that are somewhat different from those found in
living woods.
Fossil Plant Record (In Different Eras)
Archeozoic Era has a dim plant record. The fossil record fails to
enlighten us as to when, where, or how life came into existence. Plants
capable of photosynthesis and the consequent release of free oxgen into
the air had certainly come into existence by middle Precambrian time
roughly 2.3 billion years ago. At about this time the oldest fossilized
organisms were alive. From the middle Huronian Gunflint chest Barghoom
and Tyler (1965) found minute objects that resemble colonies of blue-
green algae and filamentous objects with attached spores that seem to
represent fungi. Most of the Evidence of life during the Archeozoic is
indirect, in the form of precipitates of calcium, iron or sulfur. In the Belt
series of Montana large and distinctly formed reeflike structures show a
close resemblance to similar ones formed by blue-green algae of the
present day. In the Paleozoic Era the development ofland floras is started.
Remains of higher plants are scare in the predominantly marine rocks of
the earlier half of the Paleozoic Era. There is ample evidence of both
calcareous and noncalcareous algae in the Cambrian seas. An axis bearing
small, sinlple, leaflike appendages from the Middle Cambrian of Siberia
was named Aldenophyton antiquissimum. Externally the plant resembles
Fundamentals of Palynology 145
a herbaceous lycopod. 12 types of cutinized spores have warty exines
and triradiate tetrad scars. They resemble some of the vascular plant
spores found in Devonian and Carboniferous rocks. The Ordovician seas
supported rich algae floras that supplied ample food for the many forms
of invertebrates and primitive fishes that appeared during that time. The
algal floras of the Ordovician seas persisted into the Silurian. An enigmatic
plant that appeared in the Silurian was Prototaxites. The Middle Cambrian
Aldanophyton is a vascular plant, the oldest plants of this category come
from the Middle Silurian. In the Devonian exphasis shifts from the
predominantly marine algal floras to land floras composed of vascular
plants. The floras of the Lower and Middle Devonian were formerly
referred to as the Psilophyton flora, and that of the Upper Devonian, as
the Archaeopteris flora. The lycopods are especially well represented in
the Middle Devonian by several genera. Upper Devonian floras contain
a variety of lycopods. No objects definitely identified as seeds have been
found in the Devonian. Floras evolved rapidly during the transition from
the Devonian to the Mississippian Period, and the plants existed in the
latter period in greater variety and abundance then in the rocks of the
Devonian System. Several new lycopods appear in the Lower
Mississipian. The oldest seed plants, the pteridbsperms, are found in
rocks of the earliest Mississipian age. The Mississippian phase of the
New Albany black shale contains a rather large flora represented mostly
by small sterns and petiole fragments preserved in small phosphatic
Plant remains are abundant in the Pennsylvanian rocks that
represented deposition in swamps where coal was formed. In some places
large quantities of plant material is preserved in coal balls, and these
have yielded valuable information on the internal anatomy of the plants
of that period. Pennsylvanian floras, early and late, are set apart from
those of other periods by an abundance of arborescent lycopods such
as Lepidodendron and Sigillaria, giant-sized members of the scouring-
rush group typified by Calamities, the low growing Sphenophyllum, true
ferns and the fernlike Coenopteridales, seed ferns of the Lyginopteris
and Medullosa types, and early fore-runners of the conifer class, the
Cordaitales. Members of these groups are often preserved in profusion
in the shales that overlie coal beds. Equisetites closely resembles and
may have been virtually indistinguishable from a modem Equisetum. The
Mississipian and Pennsylvanian Periods were for a long time referred to
146 Encyclopaedia of Petroleum Science and Engineering
collectively as the Carboniferous because of the abundance of fernlike
foliage in rocks of the two periods. A number of form genera had been
created for the various kinds of fossil fernlike foliage, e.g., Pecopteris,
Sphenopteris, Neuropteris, Mariopteris, and Alethopteris. They are
distinguished from each other mainly by the form and venation
pattern of the pinnules. Probably the largest and most diversified
group of fernlike plants in the late Paleozoic floras was the
Coenopteridales. The largest of the known late Paleozoic ferns was
Psaronius, which appears in the Early Pennsylvanian and extends
into the Early Permian. Several families are recognised among the
Paleozoic pteridosperms, but the best established ones are the
Lyginopteridaceae and the Medullosaceae. The Cordaitales constituted
another group of seed-bearing plants of the late Palezoic coal-swamp
forests. The Coniferales apparently date from the Pennsylvanian Period.
Vast changes took place in the plant world during the Permian
Period. The cold climate that had spread over much of the Southern
Hemisphere began to extend its influence over the rest of the earth. The
lowered temperatures were accompanied by aridity. The swamps dried
up, and the lush vegetation that they supported disappeared. It was
replaced by newly evolved forms with smaller, thick, heavily cutinized
leaves. Only the groups that were able to modify themselves to the
adverse conditions were able to survive, e.g., Gigantopteris, Callipteris,
Tingia. The youngest Permian flora found in North America was described
by White (1929). Glossopteris flora spread throughout the Southern
Hemisphere during the latter part of the Paleozoic Era, occupying ancient
Gondwana-land, and remnants of it are found in southern Africa, India,
Australia, and South America. The Glossopteris flora characterizes the
lower of the two divisions of the Gondwana group. It has a total
thickness of 30,000 feet in India and other places in the Southern
Hemisphere. The upper Gondwana flora is quite different from that of
the lower series. No actual traces of the Glossopteris flora have been
found in North America.
The Mesozoic flora was initiated during the latter part of the
Paleozoic Era. In the earliest Triassic the scouring-rush order is
represented by Equisetites and Schizoneura. The principal lycopod is
Pleuromeia, a plant more than a metre high that resembled a dwarf Sigillaria.
Neuropteridium is the most characteristic fern genus, and a few fronds
Fundamentals of Palynology 147
are referred to Zamites and Pterophyllum. Voltzia is the best known of
the Early Triassic Coniferales. The most thoroughly studied Middle
Triassic flora is the Ipswich flora of Queensland. It contains the probable
pteridosperm Stenopteris, a few ferns identified as Cladophlebis and
Dictyophyllum, and leaves resemble with the modem Ginkgo. The
much richer Late Triassic flora contains Neocalamites, which is
intermediate in size between Calamites and Equisetum, numerous
pteridosperms, an abundance of cycadophytic foliage types, and conifers
resembling Voltzia. The Rhaetic is sometimes regarded as uppermost
Triassic. From the Rhaetic of Sweden comes Bjuvia simplex. Jurassic
plants range from the Arctic to Antarctic and are especially abundant in
eastern Asia, Siberia, Argentina, South Africa, India, Australia,
Great Britain and Central Europe. Almost all Jurassic floras consist of
ferns, cycads and cycadeoids, ginkgophytes, and conifers. A series of
deltaic deposits known as the Oolite contain exceptionally well
preserved foliage and fructifications of almost all of the plant groups
known at that time. In Bihar in eastern India, the Rajmahal upper
Gondwana series, which is believed to be of Late Jurassic age, contains
plant similar to those found in Jurassic rocks elsewhere. A group of plants
peculiar to this regions is the Pentoxylales. Several modem fern families
are recognizable in the Jurassic. Among these are the Matoniaceae,
Marattiaceae, Cyatheaceae, Osmundaceae, and Schizaeaceae. The
Jurassic rocks are rich in remains of conifers. Sequoria first appears
in rocks of this age in China. Typical Jurassic genera are Araucarites,
Brachyphyllum, Pagiophyllum, and Podozamites. Silicified trunks
of Cycadeoidea occur in Jurassic beds. Tempskya fern range from
the Wealden to the Senonian, it seems to be confirmed to the middle
part of the Cretaceous System. Weichselia fern possibly ranges into
the Late Cretaceous. Two other ferns are knowltonella and Schizaeopsis
from the early and late Early Cretaceous, respectively. The Cretaceous
was an important period in the history of the plant kingdom. It was
during this time that the ferns and gymnosperms surrendered to the
flowering plants. Overlying the Lower Cretaceous Potomac group with
its early angiosperms are the Raritan and Magothy Formations, which
are assigned to the lower Upper Cretaceous. These have large floras that
contain upto 60 percent angiosperms. The flora of the Dakota Sandstone
contains 460 named species. 99 percent of these are angiosperms. All
Late Cretaceous floras are dominated by angiosperms, and they consists
largely of families in existence today. Even the ferns are modem. The
148 Encyclopaedia of Petroleum Science and Engineering
plant fossils that are most commonly encountered in Upper Cretaceous
rocks are leaves that resembles those of laurels, figs, oaks, and other
broad-leaved trees of today in forests of moderately warm and well-
watered regions.
Modem floras of the Cenozoic Era come after the Mesozoic flora.
Warm climates extended into far northern latitudes during the Paleocene
and Eocene Epoches. Palms thrived in southern Canada, and pines,
birches, and willows grew in land areas now only 8 degree from the North
Pole. One of the largest of the early Tertiary floras is the Wilcox flora.
This floras ranges from Alabana to Texas and consists of several hundred
species .that represent 180 genera and 82 families. It bears a close
resemblance to the Recent flora of the Antilles and Central America.
Legumes are the dominating elements in this flora, but there are numerous
members of the Lauraceae, Araliaceae, Me1iaceae, Moraceae, and
Palmaceae. The Green River flora of Wyoming, Colorado, and Utah
contains abundant algal remains that must have originated in warm,
shallow water. The Green river flora also contains cycads, conifers, palms,
figs, sweet gums, laurels and oaks. For three centuries casts of seeds
and dry indehiscent fruits have been collected in large numbers where
they weather out of the Eocene London clay along the Thames below
London and on the Island of Sheppey. The blocking of streams by flowing
lava (between Late Cretaceous and Miocene) produced numerous fresh-
water lakes, which were in tum filled with falling ash and material freshly
eroded from ash deposits. These lake beds contain the most extensive
records of Tertiary floras known anywhere. Remains of the floras are the
best indicators of Tertiary climates. They show the increase in warmth
over northern latitudes. They also show the effect of proximity to ocean
basins by revealing marked differences between inland and coastal floras
at similar latitudes. Western American floras existed in North America
upto Miocene or Pliocene time. Some of these floras are Ginkgo,
Pseudolarix, Metasequoia, Ailanthus, Koelreuteria, Cercidiphyllum, Trapa,
and Zelkova. Large floras of early to middle Oligocene age are preserved
in the lake beds at Florissant in Colorado and in the Ruby valley in south-
western Montana, e.g., Metasequoia, Salix, Morns, Populus, Quercus,
Mahonia, Carya, Zalkova, Sassafras, Persea, Cercis, and Sapindus. The
effect of proximity to the sea is showd by the Weaverville flora in
California. It is quite different, being a subtropical assemblage, as
Fundamentals of Palynology 149
indicated by such genera as Taxodium, Nyssa, Tetracera, and Ficus. The
late Oligocene or early Miocene Bridge Creek flora of the John Day valley
reflects the return of slightly lower temperatures after the peak of the
warmth. Miocene floras are rich in such genera as Acer, Alnus, Quercus,
Populus, Salix, Prinuis, Picea, Platanus, Fagus, and Mahonia. The summers
became drier and seasonal changes become more pronounced. Several
genera such as Carpinus, Ulmus, Tilia, and Fagus persisted in the eastern
half part of the continent. The cooling trend that culminated in the
Pleistocene ice age continued to develop during the Pliocene. It was then
that the Arctic tundras. Elevation of the Cascade range during late
Miocene time reduced the rainfall to the eastward, thus initiating the desert
environments of the Great Basin and adjoining areas. The last remaining
link between Tertiary floras and those of the present are revealed to some
extent by pollen and other plant remains preserved in peat bogs of
Pleistocene and post-Pleistocene times.
Fossil Plant (Time Scale)
The conventional eras and periods of geological time are based
principally on major changes in faunas revealed in the rock succession.
Proterozoic means the age of earlier animal life. Paleozoic in turns means
the age of ancient animal life and Mesozic and Cenozoic mean middle
and recent life, respectively. Plant kingdom establishes five eras but
retains the periods of the conventional geological time. The oldest era,
the Archeophytic, embraces the oldest known rocks up through the early
Precambrian. It would include the oldest living things and the simple
organs that evolved from them The succeeding era is the Eophytic, which
extends from the later Precambrian into the Silurian. This could be called
the algal age. Vascular plants, which might have been in existence during
the latter part of the Eophytic era, first become recognizable as floras at
about the middle of the Silurian, which marks the beginning of the
Paleophytic era. This begins with the Upper Silurian and continues
through the Lower Permian. Within it appeared the early land floras of
the Devonian and the Mississippian, Pennsylvanian, and Early Permian
floras that followed. By Late Permian time the spread of colder climates
and the disappearance of the lush coal swamp forests is everywhere
manifest, and this marks the beginning of the Mesophytic era, which
extend to about the middle of the Cretaceous Period. Then floras marked
by the dominance of angiosperms characterize the upper half of the
150 Encyclopaedia of Petroleum Science and Engineering
Cretaceous Period, which represents the earliest phase of the Cenophytic
era, or the era of modem flowering plants. The Cenophytic embraces the
Upper Cretaceous and the Cenozoic of the standard sequence. The
Mesophytic and Canophytic thus each began about half a period earlier
than the conventional Mesozoic and Cenozoic, evidently due to the fact
that plant evolution had preceded changes of corresponding magnitude
in animals by approximately half a period. The stimulus to dinosaur
evolution might have been major changes in floras during the Permian,
just as mammalian evolution received a boost from the Late Cretaceous
Jurassic and Early Cretaceous PoDen and Spores
Palynology shows that plant evolution was an eventful in the
Jurassic and Early Cretaceous as in any other period of comparable
duration. The marine stratigraphic succession is well correlated in Europe
and in many other areas, and therefore dating of nonmarine successions
by palynologic correlation can be particularly effective in these periods.
Table 4 shows the stratigraphic divisions of the Jurassic and Early
Cretaceous in Western Europe. Plant-microfossil assemblages of the
Jurassic and Early Cretaceous reflect their provenance from a much more
diverse group of gymnosperms from petridophytes to bryophytes. Of
the gymnosperm representatives the bisaccates, when present, frequently
predominate. More than 100 genera have been used for the many organ
species described from this period. The most prominent type is classified
as Cyathidites (Couper, 1958), which has a concavely triangular amb and
simple long laesurae. Spores with a circular amb are found in compression
ferns such as Todites williarnsoni. Other smooth spores with the laesurae
enclosed within elevated lips are classified in Biretisporites, which has a
uniform exim. See Fig. 23. One of the most difficult spores to identify is
Calamospora mesozoica. Some smell, thick walled spores of the genus
Stereisporites are believed to represent the Sphagnales. Osmundacidites
was erected for granulate spores. Species of Pilosisporites are common
in Lower Cretaceous rocks. Kuylisporites bears distally a number of
crescentic pseudopores. Cyclosporites has a distal recticulum of high-
crested muri with an unusual proximal radial arrangement of similar muri.
Staplinisporites has radial and concentric distal muri and a distal polar
thickening. Perhaps the most striking murornate spores fall in the genus
Cicatricosisporites with distal and equatorial parallel muri. The smooth
valvate spores are included in Matonisporites. Plicatella has parallel
Period Age (Stage)
Early Barremian
Cretaceous Hauterivian
Jurassic Bathonian
Stratigraphic Divisions of the Jurassic and Early
Cretaceous in Western Europe
Definition of Beginning of
Division (Zone oj)
Leymeriella tardefurcata
Prodeshayesites fissicostatus
Paracrioceras strombecki
Acanthodiscus radiatus
Kilianella roubaudiana
Berriasella boisseri (approximately)
Gravesia spp.,
Taramelliceras lithographicum
Pictonia baylei
Quenstedtoceras mariae
Macrocephalites macrocephalus
Zigzagiceras zigzag
Leioceras opalinum
Dactylioceras tenuicostatum
Uptonia jamesoni
Arietites bucklandi
Psiloceras planorbis
Including upper and middle Purbeck beds
Including lower Purbeck beds, Portland
beds, upper and middle Kim meridge Clay
Including lower Kimmeridge Clay
Including French Aalenian Bajocian
and Vesulian (sensu Arkell, 1956)
152 Encyclopaedia of Petroleum Science and Engineering
Fig. 23. Smooth Azonotrilete Miospores (After Couper, 1958).
Fundamentals of Palynology 153
regular equatorial and distal muri and also short radial equatorial
appendages. Interradial crassitudes are clearly displayed by
Gleicheniidites, which has a smooth exine. Cingutriletes and
Taurocusporites are genera for spores with a circular ambo Forarninisporis
includes granulate to verrucate species with a very narrow, sculptured
cingulum. Contiginsporites shows a single distal set of parallel muri that
coalesces with the cingulum. Spores with a cavate separation of exine
layers are not common. Monolete fern spores are relatively rate in the
Mesozoic, the most common being Marathisporites. Aequitriradites has
a broad membraneous zona. Tsugaepollenites seems to be most
appropriate genus. Bisaccate pollen grains form a most important element
of Mesozoic assemblages. In the Jurassic there are records of the very
large Abietinaepollenites dunrobinensis with a corpus length of about
100 microns. In the Early Cretaceous species of Parvisaccites became
important stratigraphically. Monocolpate pollen is mostly unsculptured.
The most surprising colpate grain is Eucommiidites. Calvatipollenites is
monocolpate, with a finely clavate exine that become tectate. Throughout
the Jurassic and most of the Early Cretaceous the small spherical
monoporate Classopollis occurs in a large proportion of assemblages as
is the dominant form in certain facies, e.g., Perinopollenites, and Elatides
williarnsonii. Ararcariacites is a large thin, walled scabrate grain common
in the Early and Mid-Jurassic. Dispersed megaspores have a mean
diameter of over 200 microns and could in many cases be accommodated
on morphographic ground in miospore taxa, e.g., azonate megaspores,
zonate megaspores, barb ate megaspores, and pyrobolotrilete megaspores.
All the spores of this group belonged to aquatic plants of which the
main organs are unlikely to have been fossilized. They may have belonged
to the fern family 'Marsiliaceae, although it contains no precise Recent
Jurassic and Early Cretaceous (Distribution, Sequence, and Evolution
of Floras)
In Europe, there is a full rock succession, and, although much of it
was of marine origin, there were always extensive islands and
embayments with non-marine facies. The Lias a of Poland was deposited
in such an embayment, and the assemblages have been described by
Rogalska (1962). Similar assemblages from southern Sweden and other
parts of Europe show a marked rise of Osmundacidites and the
appearance of Eucommiidites. Classopollis becomes abundant and
154 Encyclopaedia of Petroleum Science and Engineering
remains so for the rest of the Jurassic Period. The assemblages are not
very different from those of the Rhaetian (Late Triassic) immediately
below, although Ovalipollis and some other Triassic genera have
disappeared. European assemblages from the stages Sinemurian to
Toarcian are less well known and thus less distinctive, because of
the effect of fairly widespread of marine transgression. Very large
bisaccate grains appeared at this time in Britan, but not in Europe.
Bajocian and Bathonian floras are well known from the classic area
of Yorkshire, England. Numbers of Tsugaepollenites and Araucariacites
increase rapidly, as do several species of Lycopodiumsporites.
Among monosu1cates the large benettitalean types become less common
than the small oval species. Callovian to Tithonian assemblages continue
to be dominated by Classopollis, Tsugaepollenites, and Araucariacites.
There is less variety in bisaccates, although these include some
grains with a short, wide corpus. The assemblages of the fIrst from
Early Cretaceous stages are marked by striking charges in the fern
spores. Cicatricosisporites becomes universal, as do to a lesser degree
Trilobosprites, Pilosisporites, and others. Aqequitriradites become
numerous among the hilates, and Schizosporis retriculatus is a
regular occurrence. Aptian and Albian assemblages are marked by a
sharp increase in the Gleicheniidites and a decrease in Cicatricosisporites,
Plicatalla, etc. Ephedripites becomes more common, and bisaccates
appear with a clear resemblance to some Recent genera. Among
megaspores the sudden diversifIcation of Arcellites and Pyrobolospora
is striking.
In northern temperate areas many assemblages have been described
from Asia, but they are not very different from those in Europe.
Cycadophytes would be more common in lower latitudes and
coniferophytes more abundant further north. In the "tropics"
Chlamydospermae such as Eucommiidites and also Classopollis
predominate over saccate and monoporate conifer grains. In Australia
(Southern Hemisphere) Cicatricosisporites is much less diverse, and
Plicatella does not appear. Exesipollenites is an important element with
Classopollis in the Early Jurassic. Polysaccate conifer grains are suddenly
important in the Early Cretaceous. The Albian in Australia is characterized
by the unusual Hoegisporis.
The Jurassic and Early Cretaceous were periods of very varied
selection for new types of spore and pollen apertures, some of which
Fundamentals of Palynology 155
originated in Late Triassic time. The pollen apertures seem to culminate
in the tricolpate type just before the Cenomanian age. Spore exine
sculpture shows much greater variety than at any time since the
Carboniferous, particularly in the Early Crataceous. Monosaccate pollen
becomes much less important after the Triassic. The variety and size of
the bisaccate conifer pollen decrease through the Jurassic, and the trend
changes only with the sudden increase ofParvisaccites in the Barremian.
Podocarpidites is rare through the Jurassic and into the Early Cretaceous.
There are Early Cretaceous macrofossils ofPinites leaves and cones. Any
evolution is not found in the small-grained nonsaccate gymnosperms
represented by Spheripollenites and Inaperturopollenites, which are
closely parallel pollen of some living trees. Monosulcites type of grain
does persist unaltered to the present day in living cycads. Classopollis
appears to provide one extreme of the logical development of all-sound
germinal apertures by the zonosulcate method. Species ofEurommiidites
are distinctly smaller in the Early Cretaceous than the type species in
the Jurassic. Strongly sculptured fern spores is well illustrated by
Bolkhovitina (1961). The exine sculpture pattern of angiosperm pollen
become subsequently modified in more subtle ways. Many of hilate
spores certainly represent bryophytes of which macrofossil evidence is
unlikely to be found for preservational and paleoecological reasons. By
their very nature fresh-water vascular plants are unlikely to have sufficient
cuticle to favour reasonable preservation of macrofossils. Their
requirements for distribution lead to the development of elaborate
structures for floating, for entangling, for water seal against premature
growth in their usually thick-walled spores. Throughout the Jurassic and
Early Cretaceous magaspore "species" are much more numerous than
the known heterosporous land plants.
Late Cenozoic Palynology
Late Cenozoic floras can be compared with living plants on a more
detailed taxonomic basis than can older floras. The large amount of detail
available from late Cenozoic floras emphasizes considerations that are
not usually as apparent in older assemblages. In many instances much
could be learned from the comparison of modem pollen rain with late
Tertiary pollen assemblages. The late Cenozoic includes the Miocene and
Pliocene Epochs of the Tertiary Period and the Quaternary period. The
Quaternary Period is comprised of the Pleistocene plus the Holocene
Epochs. The best documented late Tertiary floras are from the middle
156 Encyclopaedia of Petroleum Science and Engineering
and high latitudes of the Northern Hemisphere. Late Cenozoic floras differ
from earlier ones. These characteristics of late Cenozoic floras are given
1. Decreasing diversity of flora.
2. A higher proportion of fossil-plant forms from late Cenozoic
assemblages can be placed in living genera or species than can
forms from early Cenozoic floras.
3. Pollen of certain families fIrst appearing or becoming abundant
in the Neogene can be useful as indicators oflate Cenozoic age.
The fIrst occurrence of pollen of Compositae is a stratigraphic
marker for the late Oligocene or early Miocene all over the world.
Also certain herbaceous as well as woody angiosperm are
included in highly evolved families.
4. A large proportion of Neogene plants or their close relatives
are now living near their Neogene sites of occurrence, but
typically only a small proportion of such plants or their near
relatives in Paleogene floras are now a part of the local flora.
This characteristic is evident on both the generic and specifIc
5. Unlike most of early Cenozoic age, late Cenozoic floras typically
demonstrate marked provincialism Assemblages of post-middle
Miocene age may differ widely within small areas; this is
apparently the result of latitudinal and topographic
differentiation during the late Cenozoic. Because of this
differentiation the distances over which floras can be correlated
are lessened for Pliocene and younger assemblages.
Late Cretaceous and Early Tertiary Palynology
The Late Cretaceous began under conditions of major worldwide
marine transgressions that reached maxima during Cenomanian-Turonian
and Maestrichtian times. The transition from Albian to Cenomanian time
saw the continued increase in flowering plants, with some decline in
pteridophytes. The transgressions, regressions, and orogenies occurring
over the whole internal coincide with extraordinary evolutionary
developments in insects, flowering plants, and placental mammals.
Reconstruction and interpretation of the floral world of Late Cretaceous
time rests primarily on the evidence afforded by the study of leaf
Fundamentals of Palynology 157
impressions. Here floras from Greenland, Western Europe, Siberia, Japan,
China and North America have played prominent roles. The pattern of
evolutionary change that occurred within the major groups of vascular
plants during the transition from Early into Late Cretaceous time seems
remarkably similar wherever floral successions have been studied.
Fig. 24 gives the selected stratigraphic divisions of the Late Cretaceous
Upper Cretaceous
European Stages
Montian - Daman
.j Campanian
J SantOnian
U S. Gulf Coastal Ptam
Jackson Stage
Claiborne Group
Wilcox Group
Midway Group
Navarro Group
Taylor Group
Austm Chalk
I-_T_uron_ian______ Eagle Ford Shale
~ - - - - - - - - - - ~
Woodbine Formallon
Fig. 24. Selected stratigraphic divisions of the Late Cretaceous and early
Tertiary (After Tschudy and Scott, 1969).
and early Tertiary. Newer palynological analysis of mid-Cretaceous
sediments have yielded preliminary evidence that is not always
concordant with the paleofloristic and paleoecological interpretations
based on leaf floras. Comparisons of the plant microfossils and
megafossils of the Perutzer, Dakota, and Raritan Formations will illustrate
this point. The Perutzer flora of western Czechoslovakia consists of more
than 230 species ofleaf, fruit, and seed remains. More recent stratigraphic
assignments have suggested an age range from Aptian to Cenomanian
for the Dakota Sandstone throughout the wide area of its development
in western interior United States. A third well-known early Late Cretaceous
assemblage is the Raritan flora of Eastern United States.On strong
megafossil evidence, supported by some faunal evidence, the formation
is outcrop is of Cenomanian age. In their study of eight Portuguese
samples ranging in age from Aptian to Cenomanian Groot and Groot
158 Encyclopaedia of Petroleum Science and Engineering
(1962b) recorded 46 species of spores and pollen of which some 31 species
were of pteridophytic or gymnospermous affinities.
Pteridophytes, especially ferns, tend to be well represented by trilete
and monolete spores. Species of Trilobosporites, Pilosisporites, and the
more bizarre schizaeaceous types known from Lower Cretaceous deposits
are absent or rare. The widespread transgressions of the Cenomanian
seas swelled to their maxima during the next Turonina Epoch. Turonian
megafossil evidence, confirmed at least by Northern Hemisphere
microfossil records, attests to the attainment of full dominance by the
angiosperms and to a slow decline in the number of fern, cycadophyte,
and conifer genera. See Fig. 25. Cretaceous and Tertiary palynological
~ 5 0
~ 20
10 ,
Fig. 25. Total fossil pollen and spore groups Lower Cretaceous-Pleistocene
(After Cousminer, 1961).
studies from 1930 onward have tended to establish Central European
sequences as standards for correlation purposes. Generic similarity may
exist in widely separated Turonian assemblages across much of Eurasia
and North America, but perhaps not south of the Tethyan geosyncline.
The Northern Hemisphere Turonian plantmicrofossil record is
distinguished from the Cenomanian record by two features : (1) the first
Fundamentals of Palynology 159
clear dominance of angiosperms over pteridophytes and gymnosperms,
and (2) the prevalence of a morphological type of nonporolate
dicotyledonous pollen of remarkable variety, whose many form genera
are usually grouped under the morphologic category Normapolles Plug.
Turonian Normapolles types, such as Monstruosipollis Krutzsch,
Extratriporopollenites Pflug, and others, are characterized by complex,
often protruding and vestibulate, pores. A general post-Turonian decline
and extinction of inadaptive species after minor climatic deterioration
during Coniacian-Santonian time may have accounted for the
disappearance of some Normapolles types. See Fig. 26. The surviving
S 10
Fig. 26. First and last appearances of Mesozoic fossil pollen and spores
(After Cousminer, 1961).
Normapolles-producing dicotyledonous plants presumably were
ancestral to many of the modern dicot genera appearing in the oldest
There is no paleobotanical evidence of widespread climatic or other
ecological change occurring at the onset of the Senoninan and plant
microfossils of the Northern Hemisphere reflect the continued
diversification and migration of the now completely dominant
angiosperms. Southern Hemisphere spore-pollen floras of similar age
remained dominated by conifer pollen. Nothofagus and Proteacidites make
their fIrst appearance in New Zealand during the early Senonian. The
angiosperm component of the earliest Northern Hemisphere Senonian
160 Encyclopaedia of Petroleum Science and Engineering
pollen floras remains characterized by Norrnapolles forms of uncertain
botanical aflinities. Toward the close of the Santonian Epoch Norrnapolles
types became associated with types displaying increasing morphological
resemblances to pollen of modern plants. Late Senoninan pollen
assemblages tend to show a mix character that is intermediate between
Late Cretaceous and early Tertiary. Middle European floras of latest
Cretaceous age reflect maximum evolutionary development of such
Normapolles types as Oculopollis, Trudopollis, and Vacuopollis, in
company with the first appearance of pollen indicating sapotacean,
nyssacean, and palm affmities. The fern-rich early Senonian floras of
South America show, by Maestrichtian time, a marked influx of palm pollen
in association with a variety of dicotyledonous types, presaging the more
modern, and typical South American, Tertiary flora. Western North
American pollen floras of Senonian age appear to show an early
attainment of a modern aspect. From late Senonian time onward the
compositions of pollen floras show an increase in the number of types
assignable to extent genera, and a rapidly growing literature attests to
the increasing use of palynology for climatic, vegetational facies, and
age studies. Future use of palynomorphs of all categories for
paleoecological studies in general, and facies recognition in particular,
seems promising.
Toward the end of the Maestrichtian Stage the last of the great
Cretaceous marine transgressions gave way to slow, worldwide episodes
of regression, attended in some places by the prolonged development
of swamp and mudflat environments and in other places by the onset of
major orogenic disturbances. Relatively few areas of the world have
records of continuous sedimentation spanning the Cretaceous - Paleogene
interval, yet no dramatic geologic event seems to bisect the time
boundary. The stratigraphy of the Mesozoic-Cenozoic passage is not
agreed on, particularly in regard to the stratigraphic position of the
Danian. Significant faunal changes, i.e., extinction of dinosaurs,
ammonites, and rudistid pelecypods, did occur at the Maestrichtian-
Danian boundary and contributed to one of the noteworthy faunal gaps
in the paleontological record (Newell, 1962). The paleobotanical record
seems to have no gap of comparable magnitude, so that the Cretaceous-
Tertiary passage appears to have occurred without drastic vegetational
change. This is not to deny that floral changes reflected in stratigraphic
floral breaks are encountered at the Cretaceous-Tertiary boundary. The
Uper Cretaceous assemblage contain many species of Proteacidites and
Fundamentals of Palynology 161
Aquilapollenites and numerous specimens of a characteristic tricolpate
grain whose colpi are located between its rounded apical angles. In the
lower Paleocene assemblages the characteristic tricolpate species is not
present, only one species of Aquilapollenites can be observed. Data from
Paleocene distribution of corals and bauxite soils and from oxygen-
isotope paleotemperature measurements adduced in support of an inferred
general cooling of the climate during that epoch, are not supported
unequivocally by paleobotanical evidence. Southern Hemisphere bearing
on character of Paleocene tropical floras hints at strong dominance by
evergreen dicotyledons and palms, with lesser representation of ferns,
grass, and Ephedra. Pollen floras contain many kinds of unidentified
dicotyledonous pollen and grains.
Late Tertiary Floras (Interpretation)
One of the most critical problems in evaluating the paleoecology of
a fossil-pollen flora is determining what constitutes evidence of local
provenance and what represents pollen drift or long distance transport.
The palynologist should evaluate three aspects: (1) the nature of the
sediment, (2) abundance of the pollen type, and (3) reworking. The taxa
identified from a fossil flora may be classified according to their present
geographical distributions or according to the distributions of their
nearest relatives. This effort provides a basis for estimating paleoclimates,
and it can provide leads for identifying some of the unknown elements
within the flora. Stratigraphic records of pollen phenotypes are enhanced
if the climatic, ecologic, and floristic connotations of the plants can be
determined. The more accurately and completely a fossil assemblage is
compared with modem plants, the more reliable will be the resulting
identifications. As a supplement to a modem pollen reference collection,
compilations of photographs and drawings of modem pollen and spores
may be helpful. Geographic affinity of a fossil flora can be usefully
expressed in terms of the floristic province in which the majority of the
modem relatives of the identified forms live today. Additionally, the
present range of minor elements in the flora can be of interest. Most
helpful in these determinations are regional floras in which the ranges of
a modem genus or its regional species are mapped. Broad floristic
provinces were defmed for North America by Gleason and Cronquist
(1964). They recognised 10 floristic provinces that have large groups of
species with similar distributions. They are given below:
1. Arctic or Tundra Province : Silene acaulis, Betula glandulosa.
Encyclopaedia of Petroleum Science and Engineering
Northern Deciduous Forest Province: Larix laricina, Abies
balsomea, Picea mariana.
Eastern Deciduous Forest Province: Fagus, Magnolia acuminata,
Castanea, Gymnocladus dioica, etc.
Costal Plain Province: Taxodium, Nyssa aquatica, Osmanthus.
West Indian Province: Rhizophoza, Dipholis, Guettarda, etc.
Prairies or Grassland Province: Various Gramineae, Buchloe.
Cordilleran Forest Province: Pseudotsuga taxifolia, Sequoia,
Abies lasiocarpa, Tsuga heterophylla, etc.
8. Great Basin Province: Sarcobatus, Pinus monophylla.
9. Californian or Chaparral province: Arbutus menziesii, Fremontia.
to. Sonoran Province: Larrea, Fouquieria, Bursera, Sirnmondsia.
Genera now occurring in the Eastern Deciduous Forest and Coastal
Plain provinces are common in the Miocene of the Western United States,
e.g., Carya. Other eastern elements were widespread in the Western States
and Alaska during Miocene time, e.g., Liquidambar, Nyssa, Fagus,
Castanea, etc. These then grew with eastern hardwoods over a large area
in western North America. Miocene pollen documents the presence of
many East Asian genera in the New World Miocene, e.g., Pterocarya,
which now has a limited distribution in China, Japan, and in the Caspian
Sea region. It also was widespread in the United States, Canada and
Alaska. Other East Asian genera with a similar history include
Sciadopitys, Eucommia, Cunninghamia-Glyptostrobus, and Melia. It would
seem that climatic preferences and ecological relationships of modem
vascular plants apply in detail to Pliocene floras and in general to those
of Miocene or Oligocene age. Northwestern Europe has been the scene
of much palynological activities since the 1930 'so Much European pollen
work has dealt with the Rheinische Braunkohle from the Rhine and Elbe
River deltas- near Amsterdam, Cologne, and Berlin. These deposits are
coastal moor and marsh sediments that range in age from middle
Oligocene through early Quaternary. The Oligocene and Neogene floras
of these deposits are diverse: remains represented include leaves, fruits,
seeds, wood, and pollen. The general sequence as inferred from pollen
and megafossil evidence indicates a cooling of climate from at least
middle Oligocene through the Praetiglian, or fIrst glaciation. The floristic
changes of the Europe Neogene resulted partly from secular cooling, but
Fundamentals of Palynology 163
the changes were probably ameliorated by the presence of the Tethys
sea during the Neogene. Some portant numerical changes taking place
in pollen representation between the middle Oligocene and middle
Miocene include these : (1) decrease in the species Tricolpopollenites
liblarensis and Triporopollenites robustus, (2) decrease in the triporate
pollen, and (3) increase in the Alnus, Fagus type and both winged and
non-winged conifer pollen. Teichmuller (in Ahrens, 1958) has described
a possible reconstruction of Miocene plant communities from the coastal
marshlands. See Fig. 27.
Open water
Coal,; from torest swamps
Detrital Gyttl8s
Fig. 27. Inferred moor types of the Miocene niederreinische Braunkohe in their
probable lateral succession (After TeichmiilIer, 1958).
Early Miocene pollen floras have been described from Silesia and
from the Lausitz basin. Late Miocene pollen floras are known from Stare
Gliwice in Silesia and from the Konin deposits. Pollen and seed floras
from Mizerna in southern Polland represent the early Quaternary section
through Mindel and probably include the latest Pliocene. The Polish
Miocene is rich in Tertiary relict genera. See Table 5. In Fig. 28 the relative
importance of various geographic elements in the floras is plotted
according to geologic age. In Poland pollen of Gramineae and
Compositae are rare or lacking in the early Miocene but become more
common in younger beds. Megafossil evidence of arctic species does
not appear in Poland until the Mindel, or third European glaciation.
Hungarian late Miocene and early Pliocene floras have a general similarity
to floras of similar age from north-western Europe. Pollen, spore, and
plankton floras from primarily marine deposits of late Oligocene, Miocene,
and Pliocene age in Romania are summarized. Each of these floras is
distinctly more cool temperate than are floras of corresponding age from
northwestern Europe. The evidence from Miocene and Plio-Pleistocene
pollen floras of the Russia is summarized in a series of maps showing
Percentages in the Total Pollen Count of Certain Tertiary Relict Groups in the Late Cenozoic of Poland
Taxon M,ocene
Taxodiaceae, Taxaceae, 4 - 80
and Cupressaceae
Castanea and Castanea type 1-43
Nyssa and Nyssa type 1 - 18
Symplocaceae and
Sapotaceae 1- 6
Tsuga 0-1
Querclls (and
quercoid pollen) 0-5
Liquidambar +
Pterocarya 0-2
Carya 0-1
Occurrence is documented by megafossil evidence.
+Percentage is less than I.
Miocene Pliocene
1 - 20 0-1
2-5 0-1
1 - 20 1 - 5
1 - 3 -
0-7 0-4
0-2 0- 1
M,zerna II
(= Tigllan)
o - 5 (SciadopltysO)
0- 15
0- 1
Mizerna III
(= Cromerian)
Fundamentals of Palynology 165
Fig. 28. Decreasing geographic elements in late Cenozoic floras of South em
Poland (After Tschudy and Scott, 1969).
inferred vegetation patterns. Early Miocene vegetation of the Russia is
thought to have been subtropical in eastern Europe north of the Black
Sea as far north as latitude 55 degree; subtropical elements were present
in a predominantly warm temperate forest vegetation in northern White
Russia west of the Urals and in the Far Eastern province along the Pacific
Coast. The remainder of the Russia where records are available, which is
the entire midcontinent west of Lake Baikal, had primarily a rich, forest
flora of warm temperate character. Floras around the North Pacific basin
were similar on a generic and in many cases even a specific basis during
the early and middle Miocene. Altitudinal zonation existed during the
middle Miocene, when confier forests dominated the highlands above
700 metres, but mixed hardwoods of a temperate character grew in the
lowlands of the Pacific Northwest and in the southern Alaska. The cooling
of the late Miocene brought about a severe reduction of temperate woody
forms in Alaska and a restriction of these forms to low elevations in
nortliwestern conterminous United States. On a generic basic the Alaska
flora was modernized by the end of Pliocene. The floras of high latitudes
(Alaska and nearby Siberia) and those of the Pacific Northwest had few
species in common by Pliocene time. Hence, through the latitudinal
differentiation of climate during the Neogene the temperate floras of old
and New Worlds became isolated from each other. A sequence of late
Oligocene and Neogene leaf and pollen floras of the Cook Inlet area and
of the Alaska Range in southern Alaska spans much of the late Cenozoic.
166 Encyclopaedia of Petroleum Science and Engineering
The latest Oligocene pollen floras are characterized by the presence of
extinct taxa, e.g., Aquilapollenites, Orbiculapollis, etc. A feature of the
Neogene pollen floras is the appearance and increase of groups now
characteristic in Alaska, e.g., Cyperaceae, Typha, Artemisia and
Compositae, Polygonum etc. In southern Alaska during the middle and
late Miocene plant evidence indicates a major deterioration of climate.
During the middle to late Miocene a group of genera became extinct in
the region, e.g., Fagus, Liquidamber, Nyssa. The Neogene climate in the
Pacific Northwest, as indicated by pollen evidence was warm temperate
to subtropical in the Miocene and temperate in the Pliocene. Neogene
megafloras of Japan has been summarized by Tanai (1961).
A late Oligocene or earliest Miocene floras at Creede, in south-
western Colorado in the San Juan Mountains, is severely depauperate
compared to the early Oligocene Florissant flora but includes many genera
that now grow in Colorado. Recent potassium-argon isotope dates
establish the age of the Creede flora at 26 million years. The Troublesome
Formation in Middle Park, north-central Colorado yielded a pollen
assemblage from a vertebrate horizon of middle Miocene age, e.g., Pinus,
Acer, Gramineae, Umbelliferae, etc. Like the Creede flora, the assemblage
is composed dominantly of pine and spruce pollen. Pliocene floras from
Wyoming, Idaho, and Arizona have a generic aspect similar to those from
Colorado. A leaf flora of late Miocene age at Trapper Creek contains forms
such as Sequoia, Carya, Nyssa, etc., now exotic to the Rocky Mountains,
plus forms now characteristic of the area, e.g., Pigus, Abies, Acer, etc.
The pollen flora of the Salt Lake Formation and of the Banbury Basalt
are greatly impoverished compared with the Trapper Creek flora. A diverse
pollen flora from the Glenns Ferry Formation of Blancan age in the western
Snake River plain represents plants now native to Idaho, except for rare
pollen of Carya and Ulmus-Zelkova. The succession of Miocene,
Pliocene, and Quaternary pollen floras from southern Idaho demonstrates
grac,lual loss of broad-leaved tree genera that still persist in Central and
Eastern United States and along the Pacific Coast. The loss of broad-
leaved trees from the flora of the central and northern Rocky Mountains
was undoubtedly progressive, owing to gradual deterioration in regional
climate and the rise of mountains. Though two or three leaf floras of
Miocene age have been reported along the East Coast. Reconnaissance
work provides a skeletal picture of common pollen types in three Miocene
formations in Maryland, i.e., the Choptank and Calvert Formations, both
of middle Miocene age, and the St. Mary's Formation of middle and late
Fundamentals of Palynology 167
Miocene age. Most of the plant group identified area represented in the
modem flora of the region. Ephedra does not grow in Eastern United
States. Miocene pollen floras from Eniwetok, Fiji, Bikini, Palau Islands,
and Guam indicate that the Miocene vegetation contained Micronesian
plant genera that since have been eliminated from the islands. Early and
middle Miocene pollen floras of New Zealand are dominated by
Nothofagus. Bombax and Capaneidites types make their last appearance
in the late Miocene. The Gatun Formation (Miocene) in the Panama Canal
Zone furnishes evidence of Miocene vegetation in the New World
tropics. Pollen and spores types were reported: Bombax, Anemia, Trichilia,
Cupania, Roupala etc. In Panama Canal Zone, there have been few
alterations or generic eliminations from the flora since Miocene time.
Late Tertiary Floras (Summary)
In the Northern Hemisphere at high and middle latitudes pollen
evidence records a Miocene climate that was warmer and with less
seasonal variation than at present. In many areas subtropical plants, such
as members of the Sapotaceae and Meliaceae, grew alongside warm
temperate and cool temperate plants. These groups for the most part are
not found together today, but they grew only a few miles apart in
mountainous terrain of the subtropics. Though the late Oligocene
Climates brought some subtropical elements as far north as latitude 63
degree N in Alaska and the Russia, most of these genera extended only
as far north as about latitude 40 degree N during the early Miocene along
the Pacific Coast of North America and to about latitude 50 to 55 degree
N in Europe and maritime East Asia. Today subtropical elements extend
northward to about latitude 25 degree N in most areas. The early Miocene
vegetation occupying the mid-latitudes of the Northern Hemisphere was
mixed warm temperature and SUbtropical, with the true tropics apparently
restricted to relatively low latitudes, i.e., 35 degree N. Middle Miocene
leaf floras of Japan and the Pacific Coast of the United States indicate
that the climates were warmer than early Miocene ones and that some
subtropical broad-leaved evergreen elements moved northward to about
latitude 45 degree N during that time. Many genera now restricted to the
humid Eastern United States and to temperate parts of China and Japan
ranged into Western United States and Europe. Limited evidence from
low latitudes suggests that Miocene floras these were not significantly
different from the local floras of today.
By late Miocene time subtropical elements retreated to a position
south of latitude 40 degree N, leaving the north latitude a region of strictly
168 Encyclopaedia of Petroleum Science and Engineering
temperate vegetation, even in Siberia, Alaska, and coterminous United
States. An exception is Western Europe, where a few subtropical forms
persisted as far north as latitude 50 degree N until Pliocene time. During
the late Miocene a temperate flora that was relatively homogeneous on
the generic level occupied lowlands in the entire North Pacific Basin,
though montane vegetation was more boreal in aspect. Now desert areas
of Western United States and South-Central Russia showed development
of steppe or subarid scrub vegetation as early as late Miocene. In
Pliocene time the widespread climate deterioration decreased the ranges
of temperate plants. The role of Pinaceae increased significantly in the
high northern latitudes, replacing the earlier abundance of mixed
hardwoods and Taxodiaceae. Pollen of herbaceous groups was
increasingly important and more diverse than earlier. Deserts developed
in the sea of Aral area of southwestern Russia and the Great Basin of
Western United States, and semiarid conditions developed in the
rainshadow of the Rocky Mountains in Colorado and Wyoming. By
Pliocene time the mesophytic hardwood floras of Old and New Worlds
were separated by the opening of the Bering Straits and by climatic
barriers that limited the northern distribution of temperate plants to relict
Mississippian and Pennsylvanian Palynology
Most spores and pollen grains from Mississippian and
Pennsylvanian rocks are believed to have been derived from vascular
plants. These spores may be homospores, which are essentially the same
size for a given species. The homospores, microspores, prepollen, or
pollen have been called small spores, denoting a size generally less than
200 microns. Most Paleozoic spores can be divided into groups on the
basis of symmetry: (a) bilateral and monolete, and (b) radial and trilete.
A third division, alete, would include spores and pollen grains that lack
an aperture. The presence of a vestigial trilete aperture in members of
the Pinaceae is strong evidence that Pityosporites and other Paleozoic
bisaccate genera have radial symmetry. Bilateral, monolete spores
assigned to the genus Laevigatosporites are a conspicuous part of
Pennsylvanian assemblages throughout the world. Radial and trilete
spores, the most abundant spore types, occur throughout the
Mississippian and Pennsylvanian Periods, e.g., Calamospora, and
Punctatisporites. See Fig. 29. Radial, trilete spore without equatorial
structures tended to preserved or flattened in good proximo-distal
Fundamentals of Palynology 169
Fig. 29. Mississippian-Pennsylvanian spore genera (After Tschudy and
Scott, 1969).
170 Encyclopaedia of Petroleum Science and Engineering
orientation. Radial and trilete spores possessing continuous equatorial
structure are present in Mississippian and Pennsylvanian strata. Radial
and trilete spores which are roundly triangular to triangular in proximo-
distal view and which posses continuous equatorial thickening tended
to be flattened in good proximo-distal orientation, e.g., Murospora.
An ideal system of classification is one in which only morphologic
features are required to classify fossil spores and pollen. Theoretically,
according to the "International Code of Botanical Nomenclature", a single
texon may have but one valid name based on priority and other features
of the code. Richardson (1964) and Butterworth (1964b) reported their
fmdings relative to the stratigraphic distribution of genera. See Fig. 30.
Most Mississippian and Pennsylvanian spore and pollen genera are radial
AND Kosanke, SU'fton. Wonless, ond WoN
'" W_.(963) Wanless (1963)
I- MISSISSIPPI Willmon (1960)- Playford (19621 Read and Mamoy

VALLEY 11964)
en Playford (1962)
V> >-
'" z ...
a: .,

1111111 1IliHI
fil .,
., 0:

IOnlyUppcr CatbOnlf.rOt,ls pori of Nomufloft Sh'YWft (Wonlul.1963. P '5)
Fig. 30. Selected stratigraphic divisions of the Carboniferous Systems of United
States, Western Europe and Russia (after Tschudy and Scott, 1969).
Fundamentals of Palynology 171
and trilete. We should consider morphology and afftnities of radial and
trilete sores, prepollen, and pollen. Accordingly the subject is treated
under the following categories:
1. Spores lacking equatorial structures.
2. Spores with continuous equatorial structures.
3. Spores with discontinuous equatorial structures.
4. The saccate spores, prepollen, or pollen that can be subdivided
into the monosaccate, bisaccate, and multisaccate groupings.
A megaspore may be defmed as a spore, produced by heterosporous
plants, that gives rise to t h ~ female gametophyte or mega-gametophyte.
Division of the individual spore mother cell (meiosis and mitosis) results
in four megaspores. Usually megaspores from Paleozoic plants are
significantly larger than their corresponding microspores. Some pollen
grains of modem gymnosperms and angiosperms are as larger as or larger
than their corresponding megaspores. Devonian megaspores are
appreciably smaller in diameter than Carboniferous megaspores and that
there is a continuous decrease in megaspore size from the Carboniferous
to the Upper Cretaceous. The stratigraphic occurrence of megaspores is
inevitably linked with the occurrence of heterospores plants. Triletes is
associated with heterosporous, free-sporing lycopods. They have a
stratigraphic range from late Devonian to Holocene. See Fig. 31. Sectio
Lagenicula spores are characterized by a unique structural development
of a portion of the pyramic surface resulting in an elongation, or beak, in
the apical areas of the pyramic segments. Sectio Aphanozonati spores
are characterized by being originally more or less saucer shaped and
appearing circular to oval shaped in proximo-distal view. These spores
ranges in size from 180 microns to 3000 microns. Sectio Zonales species
are characterized by the presence of an equatorial rim and a zone
composed of anastomosing appendages that form a more or less solid
flange, or open. Sectio Triangulati spores are characterized by the
presence of an equatorial, solid, membranous flange and are of small to
medium size. They range in size from 350 microns to 1000 microns. Sectio
Auriculati spores are characterized by the presence of arcuate thickening
that are bulbose projections on "ears" developed at the radial extremities.
The spores are subtriangular to trilobate in proximo-distal view. The genus
Cystosporites is radial and has a trilete aperture. Fertile spores are more
172 Encyclopaedia of Petroleum Science and Engineering
Fig. 31. Megaspore genera (After Wilson, 1959).
or less oval in proximo-distal view and saclike in longitudinal. Abortive
spores are circular to oval in transverse and planes. The genus
Calamospora is unique in that the generic circumscription includes
homospores, microspores, and megaspores.
Pollen and spores, microscopic but vital elements in the life histories
of the plants they present, do no more than suggest the life form of the
Fundamentals of Palynology 173
parent plant and are not necessarily found at the locality at which the
parent plant grew. There are many limitations. Almost of the Normapolles
group of pollen grains prevalent in the Late Cretaceous are extinct. That
the plants themselves may have changed in their ecological requirements
with time must be seriously considered. When dealing with assemblages
of dispersed spores and pollen of Recent or near Recent age
palynologists have been able to do a remarkable job of reconstructing
past climates and past plant communities. Families and genera known to
be limited to restricted ecological conditions are rare. Nevertheless, when
such fossils are found careful inferences or conclusions based on them
may be sound. Inferences based on fossil associations, especially in
Tertiary and older rocks, are much more reliable than those derived from
single species. The coals derived from the different associations are
distinct petrographically. Inferences can be derived from the characteristics
of the fossils. These inferences are based on the morphology of the fossil
spores or pollen grains and include such features as the presence of
thick or thin walls and the distributive mechanisms inherent in the fossils
themselves. Float mechanisms, such as those on fossil Azolla spores,
point to an aquatic habitat like that occupied by modem Azolla species.
Inferences from adaptive mechanisms such as the wings, or sacs, on
conifers have been made. On the basis of size and sculpture we may
conclude that the fossil pollen species was probably adapted to
distribution either by wind or by insects. Entomophily, pollination by
insects, is more common in tropical humid, or rainy climatic conditions
than is anemophily, pollination by wind Airborne pollen is constantly
washed out of the humid tropical air by rain. Insect pollination under
such conditions is a more effective fertilizing mechanism. Distribution of
pollen by wind on a large scale is chiefly confmed to temperate and cool
climates. Identity of fossil pollen with pollen from extant genera and
species of plants is the most reliable basis for paleoecological
interpretation. Members of the Gramineae signify nearby grassands.
Juncaceae is a family that is composed of aquatic or semiaquatic
members. Members of the Droseraceae are limited to boggy or swampy
regions. Many members of the Chenopodiaceae are common inhabitants
of dry, open localities. Nothofagus is at present a genus confmed to the
south temperate zone.
Palynology (Applications)
The application of palynology to geologic or stratigraphic problems
involves the definition and delineation of specific strata, or segments of
174 Encyclopaedia of Petroleum Science and Engineering
the stratigraphic column, in terms of the palynomorphs derived from these
rocks. The concept that some stratigraphic segments can be identified
and distinguished from other segments is based on the fact that plants
have undergone evolutionary change during geological time. Evolutionary
change is reflected in the parts preserved, i.e., pollen, spores, and some
other structures (as well as in the plants as a whole). The preserved
remains of plants will reliably identify and distinguished segments of the
geologic column. Ecological factors, including climatic and edaphic, may
also be reflected by changes in the floras of successive rock layers. The
principal applications of palynology are to the correlation of strata and
to the determination of the relative ages of strata. Age determination must
be based on the correlation of palynomorphs assemblages of a particular
stratigraphic section with the palynomorph assemblages from a similar
section that has previously been reliably dated by some other means.
Initially dating is done by comparison of palynomorph assemblages with
vertebrate or invertebrate fossils of the same rocks. Sometimes the
principle of interpolation is employed, e.g., a continental bed, which yields
a plant-microfossil assemblage, can be given an approximate date if the
overlying and underlying strata have been dated by some means other
than pollen and spores.
Palynological Characterization of the Eocene
Early Tertiary plant mega-fossils from Holarctic recovery sites
indicate the existence of widely developed forests of mixed deciduous
hardwoods and temperate conifers. Although relatively few pollen floras
of Paleogene age have been described from high-latitude northern-sites,
the palynological evidence in general agrees with that derived from leaf,
fruit, and seed remains, and numerous genera are now known from both
megafossils and microfossils. Cranwell (1959) has alluded to the
difficulties of Antarctic collecting and to the disappointments of barren
samples. Bunt (1956) speculated that the Macquarie fossil-pollen flora
might be closely related to the Tertiary floras of the Antarctic ..
Palynomorphs from calcareous rocks collected well within the Antarctic
Circle were described. The assemblage is dominated by hystrichospheres
and dinoflagellates. Pollen are scarce and small, although well preserved.
They include Nothofagus and some palm and proteaceous forms. Pollen
size and frequency, and the association with hystrichospheres and
dinoflagellates, might indicate a deposition environment of offshore
waters of normal salinity and low turbidity.
Fundamentals of Palynology 175
The frrst extensive flora of the Neotropical Tertiary is that of the
Eocene Wilcom group of the Gulf Coastal Plain of Southern United States.
Known primarily from leaf remains and to a lesser extent from microfossils,
the flora serves to characterize the Neotropical early Eocene. The plant
families best represented from megafossils, e.g., Lauraceae, Araliaceae,
Sapotaceae, Meliaceae, etc. Jones (1961) reported that the commonest
pollen constituents were pine and oak. Wilcox flora is largely coastal and
indicates a warm temperature climate and an abundant rainfall. Wilcox
sediments from Arkansas yielded 62 spore and pollen types, comprising
a mixed assemblage of tropical, subtropical, and temperate genera,
including Anacolosa, Symplocos, Carya, etc. in company with the pine
and oak pollen. The Arkansas sediments were deposited under brackish-
water conditions. The flora of the Central American migration route
suffered more widespread selectional pressures than did the flora of
northern South America, which retains its essential Tertiary character to
this day. The middle Eocene Green River flora is yet another Neotropical
Eocene flora known from both megafossils and microfossils. The
Microfossils consist of pollen from anemophilous trees and shrubs
indicative of a temperate assemblage. The vegetation contributing to the
Green River pollen flora grew under less well watered conditions than
prevailed during an ealier and later mid-Eocene stage. The succeeding
middle Eocene Claiborne Group includes some of the most fossiliferous
sediments in the world, but its megaflora is not so rich as that of the
Wilcox. Evidence from the major megafloras of the Pacific coastal region
and the adjacent interior basins seems clearly indicative that the pre-
Pliocene forests were broadleaf evergreens growing under humid, warm
temperature to sub-tropical climates. The Chalk Bluffs flora's greatest
resemblances lie with the floras of southeastern Asia and Southeastern
United States, and those of eastern Mexico and Central America. Van
Der Hammen's (1954) palynological study oflate Mesozoic-early Tertiary
Colombian coals and lignites represents the picture of densely forested
tropical climax vegetation, marked by the cyclic fluctuations and
alternating dominance of ferns, palms, and unidentified dicotyledons.
Europe's widespread Eocene subsidence of the continent resulted
in the development of lacustrine, river-swamp, and embayment habitas.
Repeated interplay of strand-line changes and luxuriant plant growth,
continuing through the Miocene, produced considerable intercalations
of vegetational debris, with continental sediments contributing to one
176 Encyclopaedia of Petroleum Science and Engineering
of the major coal-forming periods of earth history. On the basis of plant-
microfossil evidence alone the existence of the following major
communities may be inferred for the Central European middle Eocene:
1. Swamp forests with Taxodium and Nyssa.
2. Riverbank and grove habitats of Sabal and other palms.
3. Shrub thickets of Myricaceae-Cyrillaceae species, Sapotaceae-
Symplocaceae species, Aralia, Hex, and polypodiaceous ferns.
4. Hardwood forests of fagaceous species, of Fraxinus,
Engelhardtia, Tilia, Alianthus, Pterocarya, Carya and Comus.
5. Conifer forests of Sequoia, Pinus, Picea, together with Rhub,
and schizaeaceous ferns.
As in the case of the Wilcox and Claiborne spore and pollen floras,
the London Clay pollen flora also contains grains belonging to temperate
families such as Betulaceae and Fagaceae. The most interesting pollen
found in the London Clay is Nothofagus. See Fig. 32. Most of the generic
determinations are correct and being mindful of high proportion of
Australian and Malasian genera in the London Clay flora. Eurasia served
as the "bridge" for plant migration between the southern continents. The
older podocarp forests of Australian Tertiary gave way sometime between
the Paleocene and middle Eocene to a dicotyledon-dominated
"Cinnamomum flora", which developed with considerable uniformity
across much of Australia. Leaf fossils indicating the assemblage of such
genera as Banksia, PittospoI1l1Il, Northofagus, Callitris, Phyllocladus, etc.,
suggest an equable climate with unifonnly distributed rainfall, comparable
to conditions prevailing in mountain areas of New Guinea. The families
Myrtaceae, Olacaceae, Santalaceae, etc., are represented by Eocene pollen
from numerous localities in Australia and Tasmania. Prominent pollen
geneal are Casuarinidites, Myrtaceidites, Proteacidites, Cupanieidites, etc.
The podocarp species that had dominated the New Zealand forests into
the Cenozoic were supplanted finally in late Eocene time by Nothofagus
matauraensis of the Brassi group, the group whose modem counterparts
are confined to New Guinea and New Caledonia. The New Zealand pollen
flora of the Eocene is associated with pollen of the Bombacaceae,
Sapindaceae, and Ephedraceae.
Palynological Characterization of the Oligocene
The Colorado Florissant Formation, an intermontane lacustrine
deposit of volcanic ash and tuff, is well known for the abundance of its
Fundamentals of Palynology 177
" '"
'" "-
"' u

~ UJ z
i z Z
_ MegafossIls

D Mlcrufosslls
Fig. 32. Present distribution of genera recorded in megafossil and microfossil
floras of the London Clay (After Ma Khin Sein, 1961a).
leaf and insect fossils preserved in paper shales. Except the White River
beds and certain sectors of the Bridge Creek flora, American Oligocene
plant beds are not intercalated with fossiliferous marine sediments, and
their associated vertebrate evidence has been fragmentary. The Florissant
flora is interpreted as indicative of a woody, upland flora growing under
subhumid conditions at moderate elevations. 29.7 percent of the
178 Encyclopaedia of Petroleum Science and Engineering
Florissant species have living counterparts in Asia, but 57.1 percent are
still native to the region southwestern Coahuila State, Mexico.
Gymnosperms study verify the presence of Ephedra, Pinus, Picea and
Abies. The taxodiaceous pollen encountered is morphologically more
similar to that of modern Taxodium species than to Sequoia. The
Oligocene strata of American Northwest are characterized by the
abundance of conifer pollen; by herbaceous genera represented by pollen
Graminae, etc; and by a variety of fern genera belonging to the
Polypodiaceae. The plant remains, consisting of seeds, fruit, and wood,
as well as microfossils, occur in a brown coal deposited in a small Tertiary
basin on the west side of the Green Mountains of Vermont. The flora is
considered indicative of a forest swamp growing under warm temperate
or subtropical climates.
Faunal and floral evidence both indicates the development, during
the Oligocene, of two major biotic provinces, Northern and
Mediterranean, but European Oligocene palynology is still mainly that
of the Northern province. Here sweeping strand-line changes, beginning
with the great wave of flooding at the start of the Oligocene, followed
by major regressions at the close, had produced successions of marsh,
lagoonal, and coastal swamp environments. See Fig. 33. Oligocene
flooding of the North Sea earlier had encroached into this old arc of
subsidence as far as Cologne, leaving thick sediments, of various facies,
between Bonn and Wesel. Under cooling, but still warm temperate
conditions, with average annual temperatures declining from about 20

K.J!.seler .....
\. /'5el '., . ' 0 100" n
L--__ J
Fig. 33. The transgressions of the North Sea into the North German lowland
during mid-Miocene and late Oligocene time and the distribution of the
bogs (After Teichmuller, 1958).
Fundamentals of Palynology 179
degree C in early Oligocene to about 17 degree C in late Oligocene time,
and under relatively humid conditions, at least during the middle and
late Oligocene, corals, crocodiles, some palms and sapotaceous plants
were still able to thrive. For the most part, the plant associations
reconstructed from spore and pollen analysis reflect three things : (1) a
general decrease in Palmae and Sapotaceae, (2) a general increase in
conifers, and (3) a gradual increase in Betulaceae, Fagaceae,
Juglandaceae, and herbaceous general of the Gramineae, Polygonaceae,
and Chenopodiaceae. On palynological grounds no sharp floral break is
discernible between Eocene and Oligocene. For Central Ewope the floral
character of the Neogene become fIrst evident in sediments of middle
Oligocene. The spores and pollen most frequently recorded from the
German Oligocene were derived from the following things:
1. Haploxylon and Sylvestris pines
2. Schizaeaceous, gleicheniaceous, and polypodiaceous ferns
3. Nonvesiculate Conifers
4. Oaks, elms, Tilia, Carya, Engelhardtia, Alnus, Fagus
5. Symplocaceae spp., Myricaceae spp.
The source materials for the great Miocene brown-coal "Hauptflozes"
were derived from four major forests and bog associations: (1) Sequoia
forests, (2) Myricacean-Cyrillacean shrub thickets, (3) Nyssa-Taxodium
swamp forests, and (4) Reed, sedge, grass-everglades.
Pokrovskaya (1962) has pointed out that Upper Cretaceous
and Paleogene spore and pollen complexes in the European part of the
Soviet Union are very similar to coeval complexes of Germany, reflecting
a broadly developed northern flora province during mid-Tertiary
times extending beyond the Urals and well into the Siberian plain of Asia.
The palynological characterization of the Russian Oligocene, indicated
the essential similarity of German and Russian pollen floras, noting
the' preponderance of taxodiaceous and Haploxylon Pinus pollen, and
the presence of Juglans, Carya, Fagus, Salix, Alnus, Rhus, etc. Pollen
of subtropical evergreen dicotyledons and palms is scare in Russian
Oligocene sediments. Pollen of herbaceous angiosperms is
not encountered in sediments older than Miocene. The total
pollen assemblage from the Kansu site is interpreted as indicating a dry
climate supporting a steppe-type vegetation with nearby stands of
Ginkgo and Magnolia. Families represented by the herbaceous pollen
180 Encyclopaedia of Petroleum Science and Engineering
were the Gramineae, Compositae, etc. Only a few species of tree pollen
were recorded, e.g., Betula, Tamarix, Pinaceae, etc., Much of the
palynological investigation in Japan has concentrated on the Eocene and
Oligocene sediments intercalated in the commercially important coal
seams of Hokkaido and northern Honshu. Important Oligocene spores
and pollen indicate a constant warm temperate climate for northern Japan
during the Paleogene. Arboreal pollen accounts for 70 to 80 percent of
the total number of grains in the Ashibetsu Formation of late Oligocene
De Porta (1961) has described Miocene-Oligocene spore and pollen
flora from Colombia, consisting of fern spores, podocarp pollen, and
angiosperm pollen from some dozen families, all with genera still native
to northern South America. Most of the Australian mid-Tertiary
proteaceous pollen has been described under the genera Banksieaeidites,
Beaupreaidites, Proteacidites, and Triorits. The stratigraphic ranges of
New Zealand plant microfossils show no striking differences between
the flora of the upper Eocene Arnold Series and that of the lower
Oligocene London series. The dominant forest species continued to be
Nothofagus matauraensis of the Brassi group. The interval is marked by
the first appearance of pollen representative of the Bombacaceae and
Restionaceae, as well as pollen of Podocarpus aff. dacrydioides Rich.
The first palynological evidence of climate cooling occurs in the upper
Oligocene in the strong dominance of both the Brassi and Fusca groups
of southern beeches.
Palynological Characterization of the Paleocene
Krutzsch (1957) summarized the palynological record of the earliest
Tertiary floras of Central Europe. He noted that "The transition into the
Tertiary takes place without any significant charge. The Normapolles are
somewhat shifted into the background of new form groups dominating
the Paleogene." A typical Paleocene assemblage of this province might
yield porate dicotyledonous pollen of suspected Juglandaceae,
Myricaceae, Myrtaceae, and Haloragaceae affInities, including such form
genera of Pflug as Extratriporopollenites, Intratriporopollenites,
Subtriporopollenites, and Stephanoporopollenites. In company with these
there may be found also palynomorphs of plants persisting from
Senonian and earlier times, together with palm pollen and, in low
percentages, pollen representing Nyssaceae, Sapotaceae, Aquifoliaceae,
etc., whose frequencies increase through the Eocene and Oligocene. The
Fundamentals of Palynology 181
absence or low incidence and winged conifer pollen seems to be a
characteristic feature of Central European pollen floras of Paleocene time.
Sequoia forests were thought to cover the highlands surrounding the
marshy zone. See Fig. 34. These studies bring to light the prevalence
- - . . . . , . ~
-:-:.-:-:-::-:-:-:-:-:"':...- --
~ - - - -
Fig. 34. Vegetational zones developed under altering strand-line environments
(After Kedres, 1960).
during the Paleocene of nonvesiculate conifer pollen. The climate during
much of Sparnacian time was undoubtedly tropical. Widespread deposits
of coal and lignite in the Dakotas, Montana, and Wyoming of Western
United States give evidence of the development of extensive swamp
environments after the withdrawal of the Late Cretaceous interior sea.
These organic sediments, especially those from the several members of
the Fort Union Formation (Paleocene), tend to be rich in spores and
pollen. The conifers contributed woody anthraxylous constituents, and
the angiosperms contributed cuticular and resinous constituents in the
formation of these Paleocene coals. Typical early Tertiary Northern
182 Encyclopaedia of Petroleum Science and Engineering
Hemisphere pollen floras are Ulmipollenites, Cupuliferoipollenites,
Caryapolenites, and Tiliaepollenites. See. Fig. 35.
The Australian flora, over the long stretch of time from Late
Cretaceous to mid-Tertiary, appears to have changed very little in
fundamental character. Paleocene plant-microfossil assemblages remain
dominated by podocarp pollen, although frequencies of dicotyledonous
pollen may run as high as 64 percent. Most subtropical climate persisted

Fig. 35. Paleocene pollen floras (After Tschudy and Scott, 1969).
Fundamentals of Palynology 183
in austral regions until upper Miocene times. In New Zealand pollen floras
of both the Teurian stage of the Mata series and the Dannevirka series
remain dominated by long-ranging podocarpaceous species. The low
frequency of Triorites harris ii, together with the restricted occurrence of
Nothofagus waipawaensis, serve to identify the New Zealand Danian.
The Australian-New Zealand Late Cretaceous-early Tertiary flora is the
rare occurrence of pollen suggestive of Anacolosa of the pantropical
family Olacaceae. Cookson and Pike (1954) pointed out that the presence
of Anacolsa in the Indian-Malayan flora and its absence from the modem
Australian flora provides another example of a migration toward the
equator of plants that had a more extensive southern distribution during
the Tertiary Period. Present knowledge of the classification and the
paleoecological and stratigraphic usefulness of Latin American spores
and pollen rests mainly on published papers. The Colombian Paleocene
spore-pollen floras show marked quantitative changes among certain palm
pollen from the base to the top of all sections studied. No gymnosperm
pollen is recorded, and the abundance ofPsilatriletes fern spores is much
less. Proxapertites operculatus has its greatest representation in the
Paleocene. Angiosperms constitute the entire Paleocene vegetation, and
the flora shows a definite trend toward the existing South American
aspect. The genera of recent palms are relatively wide ranging and more
resistant to temperature declines. Pollen assemblages made possible a
Paleocene age determination.
Kuprianova (1960) noted the occurrence of pollen of Cedrus, Myrica,
Ilex, Nyssa, Liquidambar, Castanea, Platycarya, the Rhamnaceae,
Mystaceae, and Cunoniaceae from Kazakhstan in Central Asia. The
angiosperm pollen is stated to have been derived from sclerophyllous
forms. The Paleocene assemblage indicated a warm temperate or
subtropical climate. The Kazakhstan record of Liquidambar is regarded
as the earliest find of sweet-gum pollen. Kuprianova concluded that this
genus and its Paleogene cohorts covered the coasts and islands of the
Tethys. A record of Platycarya (Juglandaceae) in Paleocene sediments is
interesting. The existing genus is monotypic and restricted to the
temperate Orient. The worldwide Eocene fossil record gives clear evidence
of the modem and largely tropical to subtropical aspect of the early
Tertiary vegetation. Tertiary floras give the evidence of a widespread
tropical zone ranging between 45 degree to 50 degree north and south,
with mild, continuously moist, temperate climates reaching into the polar
184 Encyclopaedia of Petroleum Science and Engineering
regions. See Fig. 36. Climates remained broadly zoned throughout most
of the Paleogene but began to modify into diverse types attending the
cooling and drying of the Neogene.
+ Cor.1 mIl
, Par,."
T ~ . _ 10 ~ 1""'JII'r.W forftH
- CII""'f Il'llluencmQ mullf'lt.un '''"ge
-'" Warm ou.n turrenl
."... CD4d 0.: .. " ("'rent
Fig. 36. Climate and climate belts in the older Tertiary (Paleocene,
Eocene, Oligocene).
Palynology Correlation
Correlation is the process of determining that geological events in
two or more areas are contemporaneous. In palynology it implies the
establishment of qualitative and quantitative similarity between the plant-
microfossil assemblages derived from two or more segments of rock
strata. A comparison with published material from other regions may yield
information of value but should not be expected to provide information
that is as reliable as that derived from nearby control samples. Two steps
are involved in the collection of data : (1) preliminary examination of the
prepared material followed by a qualitative listing of the pollen and spore
flora, and (2) a quantitative determination of the dominant palynomorphs
present. The first examination of the prepared slides should provide
information on the reliability of the sample. If the sample is reliable, the
most useful information normally gained by a qualitative examination is
a record of the total composition of the flora. The vertical range of species
is especially significant and useful. Accessory information may be
Fundamentals of Palynology 185
obtained relative to such subjects as floral origin, evolution, and the
nature of the facies and the climate at the time of deposition. During the
examination of any sample morphologic variations within species should
be noted. When the qualitative examination of a particular sample has
been completed the data are compiled as a list of genera or a list of
species. Quantitative counts have proved to be extremely useful,
particularly in local correlation problems. Such counts provide estimates
of the dominant species or forms present. The dominant forms may differ
with climatic or edaphic changes, even though no evolutionary changes
can be recognized. All stratigraphic presentations today involve
quantitative data. A sample yielding only a few species will require a
smaller count than one that yields many species. The double-count
method provides an estimate of the overall palynomorph representation.
A procedure that is often employed in making a relatively complete
qualitative, as well as quantitative, estimation is to make the quantitative
count fIrst (200 to 500 specimens), then to scan the remainder of the slide
or slides for species not included in the quantitative tally. Any additional
species would contribute to a knowledge of the complete assemblage,
and to the known vertical ranges of the scarce species, but would not
be included in the percentage figures.
Information derived from the microscopic examination of samples
should be made easily understandable to others. This presentation is in
the form of tables or graphs. A correlation diagram that incorporate
relative frequencies, absolute frequencies, maxima, minima, increases and
decreases in abundance, and ranges of groups of palynomorphs is
presented by Jekhowsky and Varma (1959). This procedure makes
maximum use of the data collected and presents it in a concise form. After
data have been assembled it is necessary to interpret these data. A
detailed exposition of a statistical method of determining correlation
between paleontologic sections, using primarily the upper and lower
extremes of the ranges of taxa recovered, has been presented 'by Shaw
in "Time in Stratigraphy" (1964). Basically the method derives on
expression of time-equivalence on a two-axis graph. One axis represents
the standard section and the other the section being compared. Another
criterion for measuring floral similarities is that employed by Couper
(1958). A percentage figure is obtained that is based on the number of
localities from a given rock unit in which a species is presented. The
relative abundance of the species at the localities is unimportant. Another
186 Encyclopaedia of Petroleum Science and Engineering
statistical method of measuring faunal or floral resemblance, based on
numbers of taxa and abundance of taxa, was suggested by Simpson
(1960). He provides 13 formulas for obtaining indices of faunal
resemblance. Correlation problems may arise from several causes. The
most serious correlation problems arise from the failure to consider
adequately the rocks in relation to the samples or to recognize either
diastems or unconformities or faunal and lithologic breaks. Rock units
are mappable lithic entities. The time required for their deposition at a
specific locality may be short and may encompass only one or a few
biozones or it may be relatively long and encompass several biozones.
Some formation or parts thereof may be barren of palynomorphs, and
consequently the number of recognizable zones within a given formation
cannot be estimated a priori.
Palynological age determinations must depend for verification on
dating methods other than the use of pollen and spores. If a palynomorph
assemblage is obtainable from rocks that are well dated by vertebrate or
other well-established fossils, then these other fossils serve to date the
plant-microfossil assemblage. Later this palynomorph assemblage can
serve as a basis for other palynologic dating. In the absence of well-
dated comparative material certain bed or stratigraphic interval can be
dated with some measure of precision if the overlaying and underlying
strata are well dated. A palynologic assemblage from such a rock unit
can thereby be dated even though no exact stratum of equivalent data is
available for comparison. Close similarity of fossil content, other things
being equal, indicates age identity. A type or control section is often
required in palynological work. If we are analysing a formation or
stratigraphic section of a known age or are trying to correlate samples
from several wells, it may be necessary to know not only the floral
changes that take place within the interval of interest but also any
changes that may occur above and b e l ~ w the interval. The sampling
interval is controlled by the problem to be solved. If we are trying
to establish the floral changes that took place at or near a known
time or rock boundary, a few samples on either side of the known
boundary usually are sufficient. On the other hand, if we are examining a
well section embracing 10,000 feet of Eocene sediments in an attempt
to establish correlation zones within such section, the number of samples
may be in the hundreds. Outerop samples should be taken from
each recognizable. rock unit that might produce palynomorphs. Cores
Fundamentals of Palynology 187
provide the best samples for establishing a control section. If a well has
been completely cored, we may then choose the most promising
lithotypes for examination. Well cuttings can be used, but ranges of
species are commonly unreliable because of mixing of cuttings.
Palynological zones can be no closer than the sampling interval. The
number of recognizable zones depends on the history of the vegetation
within and surrounding a basin and on the rate of sedimentation. The
number will be different in different regions. Assemblages or groups of
fossils are always more reliable indicators of zones or of time than are
individual index fossils. Climate changes that affect a significant segment
of the total plant flora are more likely to produce recognizable and
widespread time zones than are other factors that may affect only one
element of a flora. The known stratigraphic distribution of some groups
of palynomorphs is shown in Fig. 37. Fig. 38 is the generalized chart
showing the stratigraphic distribution of some plant groups and genera
in post-Triassic strata. During Early Cretaceous and pre-Cretaceous time
world floras were more uniform than at the present time. Floral
provincialism makes necessary, particularly in the younger part of the
stratigraphic column, the establishment of control sections for each
province or basin concerned.
Palynology may be applied to all problems amenable to solution by
the use of fossils, assuming that palynomorphs can be obtained from
the rocks in question. Pollen and spores are deposited at the same time
in contiguous or even separate continental and marine beds may permit
time lines to be drawn across boundaries between marine and continental
facies. Few other fossils can be utilized in this manner. Pollen and spores
carried by wind and water can be simultaneously deposited in continental
swamp or deltaic sites and in both brackish and wholly marine
depositional basins, thus providing time markers across extremely varied
depositional facies. The diachronous nature of a channel sand and its
matrix can be recognized in many places by the fact that the plant fossils
present in the sand are younger than those in the adjacent rock. This
recognition is particularly useful in subsurface investigations in which
the channels are not visible as such and can be recognised only by their
dissimilar fossils content. Many disconformities can be distinguished
from diastems by the pollen assemblages above and below the zone of
interrupted deposition. Coal and associated strata may contain types of
fossils other than pollen and spores. Therefore correlation of coal seams
devolves almost entirely on the results obtained from the examination of
Encyclopaedia of Petroleum Science and Engineering
1- I- ----+-+--+--+-j
------++++-+--t-t-r---I-- - - +-T',-+---l

f----------------,H'-+-I---t--- r+- -.-t---t-..-
f---- -----------1f--I--t-f--t--t-
J-HH'-If- r----- ----
I L-----______________ ___ __ __ L--__ __
1-- -
f - -

I -t----t-----1
I ?
-- 1-----
Fig, 37, Stratigraphic distributions of some palynomorph groups,
Fundamentals of Palynology
r - - ~ - - - " - - - ' - - - , " - - r - - ' -
J Pfeistoc:ene
r- --r-t-I
f----- "-----
t-t--'L-t----t-"--t----+-----t---+-- -- ---- - ._- ---.
------.---f-f- f-----+--+--+--+------- --"- -----
'---l. _______ ..L..L
--1.. __ .....L._--'-_.l.--.JL __ '--__ L__ L.. ___ --'-_-'---'
Fig. 38. Stratigraphic ranges of some post-Triassic pollen and spores in North
America (After Tschudy and Scott, 1969).
190 Encyclopaedia of Petroleum Science and Engineering
the spores and pollen that they contain. In exploratory wells the
successive strata often can be dated palynologic ally and thereby can
provide information about the depositional history of the basin. After a
control well has been examined correlative horizons can be established
on the basis of similarities in pollen-and-spores assemblages. This
information, integrated with other data, provides knowledge to guide
further drilling. Correlation diagrams involving several wells may indicate
the direction in which to look for stratigraphic traps or other types of oil
Palynomorphs (Depositions)
The factors that influence the deposition of inorganic particles also
influence the deposition of palynomorphs. These factors include particle
size, shape, density, coagulability, and the physical conditions at the site
of deposition. Some of the physical conditions of at the site of deposition.
Some of the physical conditions of significance are density of water,
turbulence, salinity, and bottom topography. A set of curves prepared
by Hjulstrom (1955) shows the interrelationships of particle size and water
velocity to erosion, transportation, and deposition. See Fig. 39. Deposits
that have been winnowed may have no pollen in the sand fraction, but a
significant increased pollen concentration may occur in the fraction that
has been removed and deposited in quite water. At the deposition site a
complex of physical, chemical and biological factors influences the
characteristics of the sediment. Terrestrial non-aquaous deposits are
< 05
Fig. 39. Approximate curves for erosion and deposition of uniform material
(After Hjulstrom, 1955).
Fundamentals of Palynology 191
mostly either from arid regions or from glaciers. They also include those
transported by gravity as talus and those developed in situ. Aquatic
depositional sites are continental, transitional, and marine. Continental
deposits include fluvial, lacustrine, and paludal. Lacustrine and paludal
environments provide reducing conditions under which pollen and
spores may be very well preserved. Transitional sites include deltaic,
lagooned, and littoral. The deltaic and lagoonal sites are more likely to
yield palynomorphs than are the littoral sites. Normal marine
environments includes the neritic, the bathyal, and the abyssal. The
neritic zone, particularly off deltas, may yield excellent palynomorph
assemblages (Woods, 1955). Bathyal and abyssal sediments are likely to
be impoverished in organic content from land-based plants but to be
enriched in oceanic organic material.
Pollen grains and spores are rarely so abundant that they make up
most of the volume of an organic deposit. Some rocks, however, may
yield an exceedingly sparse pollen and spore flora. The concentration of
pollen decreases rapidly as distance from shore increases. In some areas
the absolute fossil pollen and spore concentration per unit of sediment
may provide an estimate as to whether the sediment was accumulated
off shore or near shore. The shape of a palynomorph influences the
orientation of it in the sedimentary matrix. In general palynomorphs come
to rest with their greatest diameter parallel to the bedding plane. Nearly
all fossil grains of the genera Carya and Cirratriradites are flattened at
right angles to the line running through their proximal and distal poles.
Nearly all prolate pollen grains present an equatorial view, and most oblate
grains preset a polar view. The first noticeable effect of the weight of
overburden on palynomorphs is corripression, or flattening. In ancient
sediments a nomeversible flattening is evident. Pollen and spores are
compressed with the same attitude as that in which they came to rest,
and their shapes are the determining factors in their preferred orientation.
Pollen and spores embedded in clays are flattened to a maximum degree.
If the matrix has not been compacted, the palynomorphs, where preserved,
will retain their original shape. This preservation of shape is independent
of whether deposition is in a clay, silt, sand, or an organic matrix (bog).
Some evidence of distortion of fossils by pressure from sand grains during
compaction has been observed. Perhaps one reason for the good
preservation of palynomorphs is compression, or flattening. In ancient
sediments a nomeversible flattening is evident. Pollen and spores are
192 Encyclopaedia of Petroleum Science and Engineering
compressed with the same attitude as that in which they come to rest,
and their shapes are the determining factors in their preferred orientation.
will retain their original shape. This preservation of shape is independent
Some evidence of distortion of fossils by pressure from sand grains during
compaction has been observed. Perhaps one reason for the good
preservation of palynomorphs in some shales and coals is that these
matrices provide a protection cushion during compaction, thus permitting
only a minimum of distortion aside from flattening.
Palynomorphs (Diagenesis)
Before or during early diagenesis the least resistant parts of
palynomorphs are destroyed, probably by bacterial action. The cell
protoplasm disappears. The inner layer of the pollen grain coat, the intine,
normally does not persist. Usually the perisporiurn, particularly the thin
walled perisporia of such monolete genera as Asplenium, is readily
destroyed and therefore does not appear in the fossilized state. Coals
are characterized by a high content of lignin and hurnic acids. These
substances are the relatively resistant residues left after partial selective
bacterial and fungal decomposition of the original vegetable matter. The
resistant, original spore and pollen coats are preserved, typically as
compression fossils. During late diagenesis changes in the matrix and in
the organic fraction continue at a retarded rate as additional sediment
accumulates. Interstitial water is gradually squeezed out. After expulsion
of most of the interstitial water by compaction, diagenesis probably
ceases. The oxidation-reduction potential (Eh) of sediments is intimately
related to and perhaps more important than hydrogen-ion concentration
(pH) for the preservation of palynomorphs in sediments. See Fig. 40. This
figure shows that normal marine waters are oxidizing and that only in an
euxinic marine environment is the Eh low enough to provide a reducing
environment. Confined waters, particularly in the presence of organic
matter, rapidly lose their oxygen content. Hydrolysis of silicates causes
this environment to become alkaline as well as reducing. Biochemical
reactions initiated by micro-organisms rapidly remove oxygen and at the
same time produce carbon dioxide and hydrogen sulphide, resulting in a
lowering of pH. Some anaerobic bacteria release hydrogen, which causes
strongly negative Eh potential to be developed, and as a result strongly
reducing conditions are created.
Fundamentals of Palynology 193
+ 1 0 r---,-----...r--,---r----r----,.--,
+0 B
+ 0.6 -
- 0.2
0.6 -
. 1 0 ___
o 2 4
Fig. 40. Approximate position of some natural environments as characterized
by Eh and pH (After Garrels, 1960).
The original representation of the various pollen species will be
altered by differential preservation. There is an inverse relationship
between the percentage of sporopollenine in the pollen or spore and the
susceptibility to oxidation. Thin-walled pollen species will not survive
fossilization or subsequent chemical treatment, e.g., Cannaceae,
Musaceae, Zingiberaceae, and Populus. Well-preserved palynomorphs
are more likely to be found in rocks deposited under low pH and negative
Eh, i.e., in a reducing acidic environment. Such conditions are commonly
developed in bogs, the bottoms of lakes, and the depths of closed basins.
In ocean-bottom sediments quantity of bacteria and bacterial action
decrease very rapidly from the water-sediment interface downward.
Photosynthetic activity of algae is responsible for the precipitation of
carbonates from sea water. In the presence of organic acids such alkaline
precipitates redissolve. Most lime muds are precipitated in shallow water
due to effective oxygenation. Such sediments have a low content of
pollen and spores. Most calcareous rocks lack of abundant well-preserved
194 Encyclopaedia of Petroleum Science and Engineering
palynomorphs due to oxygenated environment. The common scarcity of
pollen and spores in red deposits, or the absence of them, has been
attributed to the oxidization and destruction of organic material. The red
colour in the sediments is caused by the oxidized state of the iron
contained in the matrix. Metamorphism consists of the postdiagenetic
alterations in consolidated rock that are brought about principally by
pressure, heat, and introduction of new chemical substances. Organic
sediments, such as peat, undergo successive changes with depth of burial
and with time. The alternation of organic material into coal is accompanied
by compaction and a decrease in volume. Coalification (metamorphism)
may change the coal to a rank so high that chemical agents will not
solubilize the coal rnatrix, thus inhibiting separation of the spores or pollen
grains from the matrix. Some pollen and spores rnay be obtained from
the shales adjacent to such coal. Depth of burial is known to alter the
organic content of shales. The carbonizing effect is caused by
overburden. Indurated shales or slates that have been metamorphosed
will not yield palynomorphs.
During the process of metamorphism, particularly in its earlier stages,
spores or pollen grains may exhibit evidence of carbonization and
cystallization before other evidences appear in the rock. Micro-crystals
may form, and during their growth they may push the somewhat plastic
exines aside. After chemical isolation palynomorphs show the imprint of
crystals. Fig. 41 shows the imprint of crystals on fossil palynomorphs.
Fig. 41. Crystal imprints on polynomorphs (XI 000) : (a) from the Permian of
Texas; (b) from the Mississippian of Montana (After Tschudy and Scott, 1969).
Fundamentals of Palynology 195
Leaching of rocks by ground water may, particularly in porous rocks,
carry sufficient oxygen through the rocks to oxidize or destroy any
organic matter that is present. Leaching is commonly in evidence in
sandstone that immediately underlies a coaly layer. These sandstones
standout in outcrops as white ledges. This kind of white leached interval
may sometimes be used to locate coaly horizons that are hidden by talus
or otherwise covered. Redeposition of Devonian spores in Cretaceous
rocks is not at all serious. These redeposited spores show much greater
evidence of corrosion and destruction than spores from the younger
deposits. Spores and pollen grains preserved in a rock, on the
disintegration and erosion of that rock, are again subjected to the effects
not only of atmosphere oxygen but of aerobic bacteria. These fossils
may be more susceptible to attack by organisms and by oxygen than are
freshly shed pollen and spores.
Palynomorphs (Sources)
The principal pollen-producing and spore-producing plants are
those of land origin. These plants include angiospermous and
gymnospermous trees, shrubs, herbs, ferns and fern allies, and, to a lesser
degree, mosses and fungi. In addition to these, flagellates, algae, and
fragments of animals and plants living in the water of the depositional
basin may and often do contribute palynomorphs to the organic fraction
of the sedimentary complex. These fossils are extremely useful additions
to the spore-pollen complex. Fossils are used in making age
determinations and also in the interpretation of ecology at the deposition
site. The disseminules of plants from the various original growth sites
were carried to the place of deposition almost entirely by wind or by
water. The principal processes normally involved in the formation of
sedimentary rocks are erosion, transportation, deposition, diagenesis, and
consolidation of particles or aggregates. Detrital sediments are those solid
particles or aggregates that and in suspension or they have finally come
to rest. Included organic particles are a part of the sediment. The product
of mechanical or chemical breakdown of sediments may consists of both
altered and unaltered rock particles, plus an incorporated organic fraction,
bacteria, fungi, and microscopic anirnallife. To this organic fraction is
added the fallout of pollen and spores from the atmosphere. Within a
depositional area other types of sediment may originate, e.g., important
deposits are carbonates, sulfates, and chloride. Significant volumes of
such sediments have accumulated during various stages of geological
196 Encyclopaedia of Petroleum Science and Engineering
time. Sediments, including the organic residues, are moved from source
areas by wind and water. Other minor agencies are ice, volcanic
explosions, or birds. Most sediments are fmally deposited under water.
Exceptions include deposits such as loess and dune sand. Once the
sediments arrive in the sea or other aqueous deposition sites, many of
the particles may be transported long distances before finally coming to
rest. Wave action, bottom currents, turbulence, or mass movement of
water may act to keep some of the fme particles, which include most
pollen and spores, in suspension for a long time. During this phase of
transport particularly, winnowing, or separation, of the fme and light
particles occurs. The average size of particles that are transported
decreases with increasing distance. The organic fraction is commonly
separated from the coarser detritus and deposited with the fme-grained
within a basin or an area of deposition may drop
their pollen or spores in situ. The pollen will then commonly be moved
about only by such currents as may be active within the area. Plants
growing in, and forming the vegetation of, a peat bog contribute relatively
enormous amounts of pollen and spores to the sediments that may
eventually be transformed into coal. Wind or water may also carry in
pollen and spores from source areas outside the bog. During the time
that palynormorphs are being transported they may be subjected to
various agencies whose effects may ch .. nge their distribution,
concentration, and state of preservation. The original distribution and
concentration of palynormorphs in a sediment may be altered by sorting,
flotation, stirring, mixing, and resettling. This alteration may result in
qualitative or quantitative change in the recovered pollen and spore
assemblage. The slate of preservation may be adversely affected by
abrasion, chemical action, or the activity of animals. The state of the
specimens may range from only slightly altered to corroded and abraded.
Differential destruction of less resistant forms could radically alter the
composition of the assemblage. Abrasion of pollen grains is usually
minimal. Chemical action including biochemical degradation is the most
destructive agent in the degradation of pollen and spores during transport.
Oxidation, or biological attack, commonly corrodes surfaces or entirely
destroys structure. The acid insoluble fraction of the organic content of
phytoplankton and zooplankton is about 5 percent, whereas the acid-
insoluble organic content of marine sediments is more than 30 percent.
Even the acid-insoluble fraction may be totally destroyed if subjected
Fundamentals of Palynology 197
for a long enough time to the effects of aerobic bacteria and fungi or to
atmospheric oxygen.
Permian Palynofloras (Areal Distribution)
From the total of palynologic evidence it is valid to accept the
existence of the two distinct Permian geographic areas of Laurasia and
Gondwanaland, whether or not we accept continental drift. The
palynologic separation of the two landmasses is one of the most striking
features in studying any distribution map of Permian miospores at the
global level. In all the major taxa there is an almost complete separation
of the two landmasses, and it is clear that India belongs to the
Gondwanian landmass. A more logical analysis is to plot world-distribution
maps of all the Permian miospores and define palynofloristic palaeobotanic
provinces with a purely empirical technique, i.e., without reference at all
to class;fjcally defined provinces. This can act as a check on the validity
of both the palynofloristic and classical palaeobotanic methods as
palaeobiogeographic tools. Distribution maps were constructed for all
of the Permian miospores. See Fig. 42, 43, 44, and 45. Few species occur
beyond the limits of particular palaeobotanic provinces. The Saccites
show the greatest member of species that transgress their normal endemic
areas and becomes exotics in a foreign province. The main mixing is on
the fringes of 6rovinces. The Cathaysian palaeobotanic province is the
most interestnig palynofloristically. It is characterized by an abundance
of typically Carboniferous genera. The Cathaysian province was a refugee
(relict flora) area during the Lower and Middle Permian Period, where the
carboniferous flora temporarily survived into the Permian Period, due to
some unknown palaeobiogeographic factor.
Permian Palynofloras (Temporal Distribution)
The generalized stratigraphic distribution of each miospore species
for each continent has been plotted on range charts and analyzed in terms
of the classical Permian geographic areas of Gondwanaland and Laurasia
(Hart, 1965). Each of these palaeogeographic areas shows distinct
palynologic characteristics that allow them to be separated. A better
understanding of Laurasian Permian palynofloras can be derived by
considering each of the Laurasian palaeobotanic provinces ofEurameria,
Angara, and Cathaysia separately. Typical Gondwanian Palynofloras have
been described by many authors. Essentially the complex is characterized
by the presence of Protohaploxypins, Cordaitina, Striatopodocarpites,
198 Encyclopaedia of Petroleum Science and Engineering
Fig. 42. Global distribution of species of proto hap lox pinus (After Tschudy and
Scott, 1969).
Fig. 43. Global distribution of species of Striatoabietites and Vittatina.
Fundamentals of Palynology
Fig. 44. Global distribution of species of striatopodocarpites.
Fig. 45. Global distribution of species ofTaeniaesporites,
Hamiapollenites, and Lueckisporites.
200 Encyclopaedia of Petroleum Science and Engineering
Vesicaspora, and various species of Sporites such as Punctatisporites
gretensis, Cirratriradites splendens, C.africanensis, C.australensis,
Granulatisporites trisinus, G. papillosus, and Acanthotriletes
tereteangulatus. The palynological similarities between Australia, Africa,
India, South America, and Antarctica during the Pennian Period are very
strong. Work on the African palynoflora has shown a forefold division
of the Pennian Period in terms of palynofloristic zones: (1) Striatiti
ilorizone, (2) Zonati Florizone, (3) Cingulati Florizone, and (4) Camerati
Florizone. See Fig. 46. Typical Euramerian polynofloras have been studied


" r t' P

" '




\'. '

=. Q





Y1' e(?3 :

.. -.1.-.
r .. ",

l }-'
: ,;..-)

\. "\ '

....... . .-
\.:...;... ...

Fig, 46. Major miospore characterstics of the Permian florizones from the
Great Karroo basin, South AfriC!l (After Tschudy and Scott, 1969).
in the European sector by many authors. Characteristic is an abundance
of saccate miospores with a smaller member of Sporites. Cordaitina,
Vittatina, Striatoabietites, Protohaploxypinus, Lueckisporites, Vesicaspora,
Illinites, Limitisporites, and Piceapollenites are common, but at the species
level there is a great difference between the Gondwanian and Euramerian
palynofloras. In Soviet Europe, around the stratotype area, data are
available from Sakmarian, Artinskian, Kungu.-ian, Kazanian, and Tatarian
stages. The Sakmarian complex is dominated by saccate Pollenites, with
Sporites forming usually less than 2 percent of the complex. The
Fundamentals of Palynology 201
Artinskian complex has as its main elements Tuberculatosporites
marattiformis, Lycospora subdola, Grarnlatasporites irregularisplicatus etc.,
and some species ofVittatina and Disacciatrileti. The Kungurian complex
is characterized by the strong dominance of Pollenites over Sporites, by
diversification amongst the genera Cordaitina, and Vittatina, by a
significant number; Cycadopites, and particularly by the wholesale
development of the disaccate Striatiti. The Kazamian complex consists
of a great number of saccate Pollenites from the genera Vittatina,
Striatopodocarpites, Protohaploxypinus, and Cordaitina. The Tatarian
complex is once more characterized by disaccate Striatiti, particularly those
belonging to the genera Striatopodocarpites, Protohaploxypinus, and
Palynological studies of typical Cathaysian palynofloras are rare. In
general the characteristics of the p:> lynoflora are an abundance of
Carboniferous relict genera, such as Torispora, Camptotriletes,
Schopfites, Densosporites, Reinschospora, and Cyc1ogranulatisporites.
Ouyang (1964) described miospore complexes from the Lungtan series
of Chekiang and lower Shihhotze series of Shansi. The palynoflora
described from the Lungtan series consisted of 70 morphotypes assigned
to 26 genera. The miospores described from the lower Shihhotze series
consisted of 64 species assigned to 31 genera. The Angaran palynoflor ..
has been studi{"d in greatest detail in the Kuznets basin, where the
palynologic succession shows very marked differences from the Permian
Euramerian palynoflora as seen in Soviet Europe. Basically the complex
consists of Apiculatisporite", Acanthotriletes, Leiotriletes, Cordaitina,
Vesicaspora, and Piceapollenites. The genera are chiefly forms that occur
in most geC'
ogicd formations. The Lower Permian Balakhonian suite is
characterized in its lower part by miospores belonging to the genera
Cordaitina and Cycadopites. Triletes are also important, particularly
Acanthotriletes rectispinus and A. obtusosetosus, associated with the
Laricoidites sirnilis. In the upper part of the Balakhonian suite
quantities of Cycadopites occur, but the complex is dominated by triletes
such as Acanthotriletes obtusosetosus, A. rectispinus, A. stimulous,
Apiculatisporis asperatus, and also the aletes Laricoidites similis. The
Strelkinskian complex was equated with the lower Kungurian stage of
the Euramerian palaeobotanic province. This complex shows a
tremendous abundance of Cycadopites (36 percent) and of triletes as
Granulatasporites pastillus, Lophotriletes polypyrenus, and
Acanthotriletes heterodontus. The palynofloristic characteristics of the
202 Encyclopaedia of Petroleum Science and Engineering
Il'inian suite are the presence of the miospores Acanthotriletes
heterochaetus, etc. The species components of the Erynakovian complex
include Cordaitina rotata, Cyeadopites Caperatus, Acanthotriletes, etc.
Although normally the Triletes are the most important, locally
Cycadopites and Cordaitina become prominent.
Permian Period Palynology
Temporal subdivisions of the Permian Period on the basis of
palynofloristic characteristics are becoming discernible. These sub-
divisions reflect two striking influences on Permian plant life. One of these
is the immense effect of the Gondwanian glacial epoch on the origin and
development of the floras. The other is the existence of a defInite areal
separation of the earth into a northern Laurasian and a southern
Gondwanian region, i.e., the classical paleobotanical provinces based on
megafossils can be delimited palynologically. See Fig. 47. At the general
level the Pollenite miospores from the major part of the Permian complexes
in the Gondwanian and Euramerian provinces and are considerably less
signifIcance in the Angarian and Cathaysian provinces. Permian Pollenites
are represented by all the major subturmae ofPotonie and in their generic
Fig. 47. Pennian palaeobotanic provinces based on leaf genera
(After Tschudy and Scott, 1969).
Fundamentals of Palynology 203
composition form a sharp contrast to both the Carboniferous and Triassic
complexes. Of greatest significance are the saccate genera, and
particularly the Disaccites. Possible interrelationships of the saccate
groups are given in Fig. 48. The basis of saccate taxonomy is in general
the degree of development of the saccus. In the Disaccites this is
expressed by the nature of the distal and proximal roots, in particular the
PennsylYanian Permian TnaS51C
Fig. 48. Relationships suggested by morphologic trends in
upper Paleozoic Saccites.
length and position on the central body of the sacci roots. In the
Monosaccites the degree of saccus development is expressed by a
proximal, distal, or proximal and distal attachment of the saccus to the
central body and by the general symmetry of the saccus. The disaccate
Striatiti, in which the thickened proximal cap is sculptured by longitudinal
ribs and striae, are typical and usually abundant in the Permian complexes,
and in terms of its microspore components the Permian Period may be
characterized as the Striatiti complex. Although the saccate miospores
are usually the most important pollenite forms, they do not form the total
complex. Finally, in the Pollenites part of the Permian complex are
miospores belonging to the Aletes. The other major anteturma of
204 Encyclopaedia of Petroleum Science and Engineering
iospores, the Sporites, in essential characteristics does not show such
a great difference from the underlying Carboniferous complex as do the
Pollenites. Representative genera of spores and pollen from Permian rocks
are shown on Figs. 49 and 50.
Fig. 49. Representative Penni an saccategenera (After
Tschudy and Scott, 1969).
Fundamentals of Palynology 205
Fig. 50. Representative Pennian non-saccate genera.
Precambrian Microfossils
The phyletic-progression chart represents a schematic interpretation
of the historical relationships in organic evolution. See Fig. 51. Some of
the major distinctions with the organic world are suggested by this figure.
Later results from organic geochemistry may at least serve to defme the
stages based on derivatives of a few metabolic products. Probably
206 Encyclopaedia of Petroleum Science and Engineering
Fig. 51. Phyletic progression in organic evolution
(After Tschudy and Scott, 1969).
geochemical distinctions actually are the most important, because, at or
near the points of dichotomy, there may have been very little morphologic
difference between the biotic elements that later gave rise to major groups
of organisms. The major taxa have necessarily been defmed in relation
to their modem diversification, and, if phylogeny is projected to a point
of origin, even major distinctions become matters of technicality. The
modem groups of microorganisms that are presumed on various grounds
to have a long Precambrian ancestry are the acquatic organisms whose
habitats also have been maintained d0w.n to the present. Several, kinds
of microfossils are present even in very ancient deposits. These fossils
are highly significant from a theoretical as well as a more practical
stratigraphic standpoint. Classification of ancient microfossils must be
based largely on inferences derived from morphologic evidence.
According to present concepts a primitive heterotrophic type of
protobiont was evolved initially from an abiotic, coacervate soup. The
initial autotrophic mechansim may have been anaerobic, and it may have
catalyzed reactions that are relatively inefficient in terms of energy
Fundamentals of Palynology 207
conversion. A more efficient synthesis was possible with the origin of a
photosynthetic pigment such as chlorophyll. Another feature of general
important in relating organic groups in the nuclear membrane. In bacteria
and in blue-green algae a true nuclear membrane is lacking. The nuclear
membrane differs from the external membrane of microorganisms. The
external membrane must have been present in all discrete organisms. The
nuclear membrane is a more specialized structure. Fusion of sex cells, or
gametes must be fundamentally considered whether organisms are
classed as plants or animals. Presumably much of the cause of
evolutionary progression must be attributed to development of an
effective means of genetic recombination, and segregation, when sex cells
are initiated. Organisms that have not developed a specific sexual
mechanism have remained conservative in their morphology, e.g.,
bacteria, blue-green algae. Fungi and protozoa have a polyphyletic
derivation. Arrows connecting separate phyletic paths indicate probable
points'ofpolyphyletic infusion. Fungi obtain food in solution, commonly
enzymatic action external to the cells. Life processes generally depend
on the coordinated catalytic reactions of many enzymes.
Other microorganisms similar to planktonic flagellated algae not only
possess chlorophyll but also are able to engulf particles of food in an
apparently holozoic fashion. The protozoa must be of polyphyletic
derivation. Most of the Precambrian palynomorphs probably do represent
phytoplankton. A point of phyletic significance liking all the sexually
differentiated organisms, animal and plant, is that all of their life cycles
include the flagellum, an organelle of amazingly uniform, yet highly
complex, organisation. All sex-differentiated organisms probably have a
common ancestry of the middle Precambrian. Even the archegoniates that
include bryophytes and all higher plants must have an ancestry touching
the Precambrian. The first archegoniates were surely advanced types of
algae. The archegonium is a special organ that provide a basis for
important evolutionary advancement. Many of the Precambrian
carbonaceous microfossils of sporelike form have been classed as
phytoplankton. Reef-like calcareous deposits of Precambrian age suggest
the presence of algae or bacteria that stimulated calcareous precipitation,
but such deposits do not commonly include actual organic remains. They
do indicate that the Precambrian microbiota was abundant. During the
Phanerozoic the sea and the atmosphere were relatively constant in
composition and the land was affected by weathering and erosion at
relatively constant rates. Vital processes have evidently existed during
208 Encyclopaedia of Petroleum Science and Engineering
more than half of the earth's past history. Photosynthesis by green plants
is presumed to account for the present concentration of free oxygen in
the atmosphere. Study of plant microfossils in Precambrian rocks should
contribute important evidence about the early history of the earth before
the atmosphere had acquired its present composition. See Fig. 52. A valid
------- ---+'--_:. __ .
staQe of :he
de .... elopment
Million years
Fig. 52. Evolution of terrestrial atmosphere and biota (After Tschudy
and Scott, 1969).
stratigraphic succession of microfossils should confIrm the interpretation
of ancient environments. The fossils that have been found in Precambrian
rocks so far do not constitute an establish independent basis for dating.
The older occurrence of Precambrian microfossils are diffIcult the
interpret stratigraphically. Timofeyev (1959) has attempted stratigraphic
correlation on the basis of palynomorphs from upper Precambrian (Sinian)
Fundamentals of Palynology 209
Precambrian Microfossils (First Vestiges of Life)
Search for evidence of extra-terrestrial life has been concentrated
on the carbonaceous chondrites, a type of meteorite with a large
proportion of carbonaceous material. Three microfossil occurrences have
been described from Precambrian deposits of primary chert. The oldest
microfossils yet known occur in cherty bands of the Fig Tree Series,
Swaziland System, near Barberton in South Africa, and have been
regarded, on the basis of isotopic dating, as about 3 billion years old
(Nicolaysen, 1962). These rocks contain definite remains of fossil
microorganisms. One species of bacilliform fossils has been described.
The best known of the Precambrian microfossils are those from the chert
deposits of the Gunflint Iron Formation in Ontario. Isotopic dating
suggests an age of about 2 billion years for this deposit. The fossils
consists of carbonaceous remains embedded in chalcedony. One of the
more distinctive forms in a tiny umbrella-shaped object with a bulbons
appendage, named Kakabakia. See Fig. 53. Sporelike bodies have been
assigned to the genus Huroniospora. See. Fig. 54. Their figure illustrates
a satellate thallus with branching filamentous appendages. Examples of
filamentous thalli are given in Fig. 55. Perhaps most distinctive are the
septate filaments. Electron-micrograph studies of the Gunflint Iron
Formation have disclosed numerous bacteria resembling the modern
iron bacillus, Sphaerotilus natans. Other forms resembling modern coccoid
types of iron bacteria are also present. The possible importance of
the Gunflint microorganisms in modifying (oxygenating) the sea
and atmosphere. Spheroidal bodies are preserved assemblage from
(c) (d)
Fig. 53. Kakabekia umbellata Barghoom (After Barghoom and Tyler, 1965).
210 Encyclopaedia of Petroleum Science and Engineering

. gl 0;'
...... .

(a) ( b)

.' .

..... "(-
(c) (d)

Fig. 54. Huroniospora and Eoastrion (After Barghoom and lYler, 1965).
upper Precambrian rocks at Bitter Springs, Australia. They have small
septate filaments, and large septate filaments, including 14 species
as members of the Oscillatoriaceae and Chroococcaceae. A modem type
of filamentous algal assemblage had appeared 800 to 1000 million years
The spore-like, or cystose, structures represent fossils that indicate
the existence of abundant plant life in the Precambrian. Membranous
forms are more common than thick-walled forms. Many of the fossils
are small and lack very definitive features. Most distinctions are based
on differences of surface ornamentation and texture. Precambrian
microfossils assemblages have been reported by Pflug (1966) from
the Belt Series in Montana. Many fossils consists of tiny, short,
multicellular filaments. Many of the cells appear to contain a darkened
residue, possibly consisting of altered protoplasmic material. Isotopic
determinations from related beds within the Belt Series suggest an
Fundamentals of Palynology 211
' 1 ~ 1
~ J
~ I \
~ ~
~ ~ .
rl l
~ . '.
. ,
. o"'.:-C
\\' "
\. ,.'\
~ . l '
,.. ,
~ . \
Fig. 55. Animikiea, Gunflintia, Entosphaeroides, Archaerestis (After Barghoorn
and Tyler, 1965).
, 'b \:
(M) (h) (i)
1-.-- ---- .- ~
Fig. 56. MilIaria, Fibularix, CatinelIa, Scintilla (After Pflug, 1966).
212 Encyclopaedia of Petroleum Science and Engineering
age of about 1.1 billion years for this material. See Fig. 56. These fossils
are different from Precambrian fossils observed elsewhere by
other workers. The fossils might represent the remains of anaerobic
heterotrophic microorganisms that were buried in situ under accumulating
sediments. If the fossils can be so interpreted, the technique
employed by Pflung might open an additional extensive field for
paleornicrobiologic investigation. The determination of botanical
relationships of this material has significance with respect to evolutionary
history of ancient plants and for its biostratigraphic use in the vast range
of Precambrian deposits.
Quaternary Floras
Early Quaternary floras differ from Neogene floras that they contain
few if an Tertiary relict genera or extinct species. Middle and late
Quatemary floras in general resemble in equivalent modem regional floras.
Many Quaternary pollen assemblages, especially those of glacial origin,
contain abundant and diverse nontree pollen. Arctic-alpine plant species
are lacking in pre-Quaternary floras, are rare in early Quaternary European
floras, and are characteristic in glacial floras of the middle and late
Pleistocene in the middle and high north latitudes of Eurasia. Sequences
of dominant pollen types are characteristic regionally for each interglacial,
and they show both qualitative and quantitative differences from the
postglacial pollen sequences. The potential for reconstructing climates
by the use of pollen floras is greater for the Quaternary than for
older periods. Because pollen identifications are usually on the generic
level, additional detail can be added to the interpretation of the
paleoclimate through the use of megafossils, which often can be
determined on the species level. The identifications of greatest potential
value will be those carried by the smallest taxonomic units, regardless of
the source of the evidence. The beginning of the Quaternary at the
type Pliocene-Pleistocene boundary in Italy is marked by a marine
regression, by the first major late Cenozoic change from warm-to-cold-
water foraminifers and mollusks, and by the appearance of new vertebrate
taxa. Paleobotanists had considered the Pliocene-Pleistocene boundary
to lie at the beginning of the earlier cool period, the Danau, or Praetiglian.
At the Pliocene-Pleistocene boundary in northwestern Europe, which is
represented by the boundary between the Reuverian and Praetiglian
dramatic numerical and qualitative floral -changes take place. The
most meaningful comparison of interglacial floras depends on having
Fundamentals of Palynology 213
a composite sequence through the Quaternary within one region
that is from northern Europe. Four criteria can be used to identify
interstades of Europe : (1) the actual chronologies or successions of tree-
pollen types, (2) the total flora represented, (3) the presence of key fossils,
and (4) the present geographic affinities of forms within the flora. The
first Quaternary interglacial or non-glacial period is represented by
extensive fossil beds at Tegelen in the Netherlands and drives its name,
Tiglian, from them. It follows the time of the Donau glaciations in the
Danube Valley but precedes the Gunz glaciations of the Alps. The Upper
Crag beds of England are also ofTiglian age. A distinguishing feature of
Tiglian interglacial beds is the fact that 9 percent of the plant species
are extinct as determined by diagnostic reproductive structures preserved
in the sediments, e.g., remains of the extinct fern Azolla teglansis.
In contrast to the Pliocene Reuver flora, which contains only 19 percent
modern Dutch species, 50 percent of the Tiglian species occur
in the modem Dutch flora. The Cromer forest-bed series of England, which
lies between the Weyboume Crag and Lowestoft Till, represents cycles
of climate amelioration and deterioration that preceded the Elaster
glaciation of Germany and is therefore equivalent to the interval between
the Gunz and Mindel glaciations of the Alps. The Cromerian interglacial
period is typified by these pollen sequence : Pinus-Betula early phase,
oak forest middle phase, and Pinus, Betula, and Picea end phase.
According to seed evidence the Cromerian flora is much like the modem
one of Britain.
The Needian interglacial of the Rhine basin of Elster-Saale age has
been correlated with English deposits at Hoxne and Clacton. The pollen
sequences and seed floras at each are strikingly similar. The same general
patterns are also seen in the Gortrlan of Ireland. The pollen sequence
from Hoxne is given as : (1) Betula and Hippophae in initial late-glacial
stage, (2) Corylus, carpinus, Picea, andAbies in mid stage, and (3) a final
early glaci!ll phase shows a rise in non-arboreal pollen types. The English
records of thermophilous oceanic species now of southern distribution,
e.g., Hedera, Hex, and Taxus, indicate a climate perhaps more maritime
than now during the mid-Hoxnian. Deposits of the last interglacial in
Denmark and northwest Germany were studied. Early arctic and subarctic
zones are characterised by a dominance of herb pollen and pine and
Betula. The middle zones show the sequence of pollen types: (1) Pinus,
(2) Corylus with Quercus, Ulmus, Alnus, and Acer. Corylus rises slowly
and makes a definite oscillation during the midpostglacial, whereas it rises
214 Encyclopaedia of Petroleum Science and Engineering
rapidly with no clear oscillation in the mid-Eemian. Also Fagus, which
enters into the sequence during the late postglacial, is absent in the
Eemian succession. The postglacial differs from the Hoxnian in that it
lacks Abies and Picea. In northern Italy an early Pleistocene pollen
sequence deposits are lacustrine and fluvioglacial terraces in the valleys
of the Re River and Seriana di Vertova. The sections are dated partly by
remains of Elephas and Rhinoceros. The Cromerian warm interval was
characterized by associations termed Carietum, Carpinetum, and
Quercetum. The Carietum wanes is importance in younger warm periods.
Intervening cold phases are characterized by increased amounts of Pinus,
Abies, Picea, and Tasuga. Pollen and seed floras of the late Pliocene and
early Pleistocene are described from Mizerna in south Poland by Szafer
(1954). A deposit on the Bug River near Warsaw is of Cromerian age.
The flora contains small amount of Carya, Juglans, Ulmus, Hex, and the
pollen of Keeteleria. Only a few American pollen studies of pre-
Wisconsinan Pleistocene floras are from isolated localities. More is known
about early and middle Pleistocene floras of Califomia than elsewhere in
the United States. The fIrst recorded interglacial yields a pollen sequence
of predominantly spruce with pine, and a predominance of grassland and
deciduous tree forms. Pollen form deposits at Quincy records spruce-fIr
forest and is of late Aftonian or early Kansan age. In the third interglacial
pollen evidence shows oscillations of pine, spruce, and grasses. Pollen
from vertebrate localities of Kansas and Oklahoma judged to be of
Illinoian age indicates a flora dominanted by conifers. Sangamonian sites
show oscillations of Pinus and grasses, Artemisia, and other compositae.
Pre-Wisconsinan floras from the West Coast are known mainly from
megafossils and are chiefly from California. Late Pleistocene floras of the
PacifIc Northwest, western Canada, and Alaska are reviewed by Heusser
(1960). Early Pleistocene floras include records from the Sonoran desert
inArizona, southwestern New Mexico, and near Channing, Tex. In Texas
pollen-and-Ieaf evidence from a lake sediment of Blancan age establishes
a western extension of Ulmus from its present range. In Eastern United
States a well-documented integlacial pollen flora is that from the Gardiners
Clay on Long Island, N.Y. of Sangamonian age, this sequence shows an
early development of boreal forest dominated by pine and spruce, and
later a rich mesophytic forest of Quercetum mixtum foIled again by boreal
forest. The Scarborough and Don beds of Toronto, Canada, contain
Sangamonian pollen sequences. Pollen of the Scarborough beds of late
Sangamonian age shows a boreal assemblages with increasing spruce,
Fundamentals of Palynology 215
fir, and jack pine. Inferred Quaternary climate patterns from various parts
of the world are incoIporated in Fig. 57.
,. ..... t.ndI Pol..." NOttfI_t Stbet., SoutM.n ten1,., UNtil(!
Z......,.. (Tl6lb) llV541 "'.r<w 1I'i631 =-__ 1'961) flint (19571
Inht'..., -.per ..... , _ A_8ft JuI ... I"CI an .. "", '"C)
"_ .. _lfFI
,. ,.
, ,

I -
Pne .... ifn

, ,
CoIOIr W .. ,.... Cvtd.r WIII',",
} )

A.ll.."OC WJ
E ........... tl9S81
.. ,'CI
,. ..
, I
Fig. 57. Summary of inferred climate changes ofthe Quaternary and late
Pliocene (After Tschudy and Scott, 1969).
Quaternary Floras (Summary)
Early Quaternary floras of the north middle and high latitudes are
notable because trends of change are widely different in various areas.
The first two interglacials of the early Quaternary are marked by definite
oscillations of climate in Europe, but only a extended cooling occurred
in Alaska and nearby Siberia. In Europe the first recorded glacial cooling
brought boreal marine species to molluscan faunas of Italy, permanently
removed subtropical taxa, and temporarily lowered the abundance of
temperate plant forms in the regions. Floras of the first two interglacials
contained fewer Tertiary relict genera than did Pliocene floras, and they
recorded temperate climates that were warmer and more equable than the
present ones in continental Europe. Though there are a few early
Quaternary records of arctic-alpine plant species, the first clear influx of
such taxa across Europe was during the third glaciation. In Mindel arctic
conditions were widespread in Alaska and Siberia. In the warming of the
third interglacial that followed, the average annual temperature was cooler
than that of present-day Europe, but growing-season temperatures were
about like now. American floristic records for the early and middle-
Quaternary either are from isolated localities, are lacking, or are not well
dated. Evidence from vertebrates and mollusks indicates that the
Aftonian, Yarmouthian, and Sangamonian interglacial climates in central
United States were characterized by reduced continentality compared with
216 Encyclopaedia of Petroleum Science and Engineering
the present. The glacial climates were also less continental but cooler
than now. The climate of the last interglacial, on the basis of
paleobotanical evidence, was warmer than present in Europe as well as
in the United States and Southern Canada.
The third through the last glaciation brought tundra or park-tundra
vegetation to Central Europe and northern Italy. In the United States
pollen records of boreal forest genera are found as far south as Florida,
the Ozark Mountains, and Texas. Plant megafossils of arctic affinities have
as yet been identified at only a few United States sites and in
Newfoundland. These sites are all of late Wisconsinan age. But pollen
assemblages suggest that park-tundra conditions may have existed in a
narrow zone attending the glacial border during the retreat of ice in late
Wisconsinan time. Some late Quaternary pollen localities from low
latitudes and the Southern Hemisphere record partial replacement of mixed
arm temperate and subtropical forest with cool temperate and boreal
forest during the Wisconsinan. Though decreases in floristic diversity
are recorded for the European floras during the early Quaternary, the
main changes in Quaternary vegetation of the Northern Hemisphere
involved cliseral migrations of existing vegetation zones (a) in north-south
directions, and (b) with altitude. Few extinctions of plant species are
recorded for the Quaternary interval.
Sample Reliability Factors
The relative reliability of samples is deter-by their source and
methods of collection. There are two broad categories: (a) samples
collected by hand or hand-operated tools, e.g., surface samples and
subsurface samples collected by hand in mines, tunnels, and caves, and
(b) samples collected by mechanical means, e.g., drilling wells, seismic
shot holes, and sea or lake-bottom. Surface samples are most readily
collected at such sites as road or stream cuts, excavations, and cliff faces,
where sedimentary exposures tend to be less cluttered by the soil mantle.
The surface layer should be removed to provide a clean exposure before
the samples are taken. Sediments directly beneath bentonite beds are
usually silicified and much more resistant to chemical and physical
deterioration. Climate has a profound effect on the degree of weathering
and produces its most striking effects in arid areas. Recent to subrecent
unconsolidated sediments may require special collecting techniques. Bog
deposits and bottom muds are cored by forcing a plastic tube into them.
The most common type of contamination in surface samples is modern
Fundamentals of Palynology 217
pollen and spores that may adhere to the surface or may be embedded
in small crevices. Such contamination can be minimized by careful
collecting and by washing before processing. Samples from rotary-drilled
wells are of three classes: (1) conventional cores, (2) sidewall cores, and
(3) cutting samples. Conventional cores are cylindrical pieces of the rock
penetrated by the bit. These cores are most reliable and are most
desirable. Most reliable samples can be obtained from wells drilled with
air or gas than with mud.
Air contaminants are most modem material. Dust in coal mines can
contaminate samples with fossil material. If the material is Recent or near-
Recent the problem of differentiating modem material is more difficult
than when working with older specimens. Modem material generally has
a different sheen from that of fossils and often takes stains differently.
Most older sediments have been compacted, and in the process the acid-
insoluble microfossils have been flattened. Samples should be throughly
dried before packing and placed in leakproof containers. If the shipping
container is likely to become wet after packing, it should be lined with
oilcloth, oiled paper, or plastic. The water supply can contain modem
pollen, spores, diatoms, dinoflagellates, desmids, etc., and in rare cases
fossils ones. To guard against this kind of contamination many
laboratories use filtered or distilled water for palynological processing.
The apparatus used for crushing samples before they are processed can
be a source of contamination unless it is carefully cleaned between
samples. Caving helps to make well cuttings one of the least reliable types
of sample. If caving is suspected, helpful information can be obtained
from the drilling report. Trips, stuck holes, reaming, and fishing are
common causes of increased caving. The usual cutting fragment is 0.25
inch or less in size. Larger fragments are caved. If several lithologies are
present, they can be sorted and possessed separately. Differences in
fossil content suggest mixed cuttings. Drilling mud can carry
contamination inthe form offme particles from formation other than one
being drilled. Samples should be washed as free as possible from drilling
mud before processing. Circulation is lost when the drill penetrates a
bed that is sufficiently permeable to drain off the circulation fluids, e.g.,
highly porous sandstones, fractured limestones, etc. When circulation
is lost, anything might plug the troublesome bed may be put down the
hole, e.g., walnut hulls, hay, or cotton-seed husks. Some of these materials
can contain pollen and spores of their own.
218 Encyclopaedia of Petroleum Science and Engineering
Reworking is the redeposition of older fossils into younger beds. It
is an inherent part of sedimentation. Its one redeeming feature is that it
shows the source of sediment. The smaller microfossils can be
transported and redeposited either in particles of their original sedimentary
matrix or, less commonly, free of matrix. When free of matrix, they are
usually corroded to some extent and less well preserved than fossils
contemporaneous to sedimentation. If they are enclosed in particles of
the original matrix, they may be redeposited in coarser clastic sediments
than they otherwise would be. In such sediments contemporary material
may have been completely removed by the winnowing action of currents
or, if left, be badly corroded. Thus assemblages can be composed entirely
of reworked fossils or may contain a mixture of reworked and
contemporary fossils. Stratigraphic leakage is the opposite of reworking
in that it is the deposition of younger fossils into older beds. It takes
place when younger sediments are deposited in cracks, fissures, or
solution channels of older ones. It occurs most commonly in limestones,
which are particularly susceptible to solution channels. Stratigraphic
leakage is much less common than reworking and seldom presents a
problem to palynologists.
Spore and Pollen Grains
The plants whose spores form the tetrahedral tetrads commonly
produce spores of the trilete type. The laesurae are the common lines of
contact of the cells in the tetrad. The tetragonal tetrad gives rise to the
monolete spore type. Spores that show neither type of laesura probably
separated early and became spherical before any texinous material was
deposited on the spore wall. Some of the thin-walled spores may be this
type, i.e., Equisetum. The primary function of spores is to distribute and
reproduce the plant. A secondary function is the protection of the spore
contents during transport and before germination. Spores of many
members of the Hymenophyllaceae are very thin wall. Spores of
Pityrograrnma possess exine ornamentation in the form of heavy ridges
surrounding the spore at the equator and regulate proximal and distal
ornamentation. This grows in comparatively dry localities. A structure
that accommodates a semirigid exine to changes in volume has been
termed "harmomegathous".
The function of pollen grains is to accomplish the transport of the
male gametophyte to the female flower so that fertilization can take place.
During Cretaceous and post-Cretaceous times a host of modifications
Fundamentals of Palynology 219
that assist in this function developed in angiosperms. Reduction in size
and abundant production of pollen are modifications that aid in insuring
fertilization of anemophilous plant. The development of viscin threads
as in the Oenotheraceae or the specialized pollinia of some orchids are
effecting the pollination of entomophilous plants. In the Oenotheraceae
the viscin threads tend to entangle groups of pollen grains that stick
together and are transported by another plant by insects. In the
entomophilous plants pollinia consist of the entire contents of the
another, or many pollen grains that are not separate, and the entire
pollinium is transferred from one flower to another by insects.
Spores and Pollen (Morphological Description)
The simplest spore type is the alete, or inaperturate, type. Such
spores are found in fossil preparations. The monolete type of spore, which
occurs in rocks from the Paleozoic to the present, is a common type. In
most modem monolete spores the perisporium is destroyed when
subjected to chemical treatment. Trilete type of spore has developed
many more morphological variations in structure as well as in sculpture
than has the monolete group. Fig. 58 shows the general terms used in
describing pollen and spores. A single fossil-spore genus may include
spores that in outline are circular, convex, or even concave. Spores may
develop modifications : radial and interradial crassitudes, or interrupted
zones, proximal or distal crassitudes, etc. A complete or partial envelope
around the spore is characteristic of many Paleozoic genera. Common
modem gymnospermous types include bisaccate and trisaccate pollen.
As the tactum over the trilete suture develops it may form large leaflike
fused extension. In the larger Paleozoic megaspores these fused
extensions of the lips of the trilete suture are referred to as massa, or
gula. The protoplasmic contents of all pollen grains are covered with a
more or less elastic membrane known as the intine. Very few species of
modem plants produce pollen grains with only this intine layer. They
have also a recognizable outer layer, or exine. The majority of
angiospermous plants produce pollen with an additional outer coat, the
exine. The exine may be thick or thin. The exine is commonly made up of
an outer layer, the ektexine, and an inner layer, the endexine. It is this
exine, that is preserved in the fossil state. The exine is the part of pollen
grain that is of greatest concern to palynologists.
The form of pollen grains is influenced by two factors : (1) heredity,
and (2) position in the tetrad. The apertures of pollen grains may
220 Encyclopaedia of Petroleum Science and Engineering
Equatorial axis
Equatorial axis
Polar axis

\ SpOre
Lateral (equatorial) view Proximal view
Proximal pol. ,.--,
Proximal polar View
Distal pole

Distal pole Distal polar view
Polar Ixis
Polar View
Equatorial view
T ricolporate
Fig. 58. General terms used in describing pollen and spores.
Fundamentals of Palynology 221
be furrows (Colpi) or pores, or both. The presence of a greater number
of colpi indicates more advanced dicotyledons. In the fossil record,
the first pollen that can be assigned unequivocally to the angiosperms
is the tricolpate form. In triporate and colporate pollen the germ pores
are situated within a furrow or colpus. In simple pollen the wall
is composed of only two layers: (1) an inner uniformly structured
endexine, and (2) a single-layered ektexine that may have external
sculpture or may be smooth. The tectate wall is made up of three or more
layers: (1) endexine, (2) columellae or granules fused at their apices to
form a "roof', and (3) sculpture elements deposited on this layer. The
common forms of pollen grains are shown on Fig. 59. These diagrams
show in a generalized form the position, type, and number of apertures.
Most of the pollen grains encountered in Eocene or younger rocks can
be outlined in this figure. Some other pollen grains from the Cretaceous
and Paleocene, cannot be placed in these categories. The Norrnapolles
group are the pollen grains that have bizarre structural elements. Pflug
(1953) has attempted to place these forms into form genera and to
describe their structure. Krutzsch (1959) described eight new Normapolles
genera. These are shown in Fig. 60. The Postnormapolles group does
not possess the bizarre germinal development, double V-mark, torus, or
Spores and Pollen (Wall Structure and Composition)
The pollen grain is commonly released from the plant maturity as a
separate cellular unit composed of a bi-nucleate or tri-nucleate protoplast
invested by a complex cell wall. The mature pollen grain is a biological
unit composed of either a cell or cells within a larger, vegetative or tube
cell, all enclosed by the massive pollen wall. The pollen cell wall is
subdivisible into two general zones: (1) an outer exine, and (2) an inner
zone, the intine. It is the exine of pollen and spores that is notable for its
resistance to chemical and morphological degradation over thousand of
years. Now most studies have focused attention primarily on the wall or
membranes of pollen and spores rather than considering the entire
protoplast in its intricate association with the investing wall. Electron
microscopy of carbon replicas of pollen and spore surfaces is of
considerable value in providing high-resolution structural details. These
have the important potential of adding a third dimension to the electron
micrographs derived from ultrathin sections. See Fig. 61. Most pollen
grains may be classified as being either without differentiated pores or
222 Encyclopaedia of Petroleum Science and Engineering
(9 (d @]


Dlporate Trlporate Stephanoporate
Per.colperate Syncolpo, .. te
htrad POIYdd
Fig. 59. Principal types of pollen grains.
Fundamentals of Palynology 223

. rro
,-- '"
, . - ,

.' ,r
I, ' ..
" ' .f _': ::
"""_ '. ___ /1,,-
Fig. 60. Principal Normapolles genera (After Krutzsch, 1959).
furrows (inaperturate) or with performed openings or thin areas
(aperturate). In the aperturate class of pollen grains there is tremendous
variations in the number, size, distribution, and structure of the apertures.
In general apertures have been related to the basic functions of
(a) provision of a place of emergence for the developing pollen tube and
(b) acconunodation to the significant volume changes that occur in the
224 Encyclopaedia of Petroleum Science and Engineering
Fig. 61. Electron micrographs of ultra thin sections.
pollen grain as a result of rapidly changing humidities. The nonapertural
exine is the outer, resistant layer of the sporoderrn. Its surface
configuration can be extraordinarily intricate and texonornically
distrinctive. The presence of ornate structuring of the exine surface has
Fundamentals of Palynology 225
been correlated in many instances with insect pollination. Functionally,
nonapertural exine has been associated with protection against excessive
water loss, irradiation, and mechanical injury (Wodehouse, 1935). In the
maturation of the sporoderm the intine is the least formed zone, or layer,
immediately adjacent to the protoplast. It is usually absent in fossilized
or acetolyzed specimens. Structurally the intine layers associate directly
with apertural structures.
Usually at the close of telophase II of meiosis a tetrad of four
micro spores is produced. The microspores are enlosed by a special callose
wall, formed within the original pollen mother-cell wall. Two patterns
of development of the usually intricate sporoderm of the mature pollen
grain or spore have been contrasted. In one of the major control of
sporoderm development is associated with the microspore protoplast,
whereas ther other pattern associates sporoderm growth largely with
external phenomena involving material of tapetal origin after the
microspores are released as individual cells from the investing special
callose wall. Exine structure is usually uniform within a tetrad. During
early meiotic stages cytoplasmic interconnections would appear to
provide for ready exchange of materials, including maternal gene products,
throughout the entire population of pollen mother cells. At the start, the
surface (plasma membrane) of each of the microspores of the tetrad
enclosed within the special collose wall takes on a distinctive
configuration that is somewhat suggestive of pinocytosis (Heslop
Harrison, 1964), which serves as a template or primexine, for subsequent
exine development. The primexine (template) of the microspore gives way
to the mature exine pattern through relatively rapid deposition of the
resistant sporopollenin. Finally, after completion of the various layers,
or zones, of exine, the intine appears between the innermost layer of the
exine and the plasma membrane.
In most taxa, during the development of the sporoderm, collumellae
appear first in ontogenetic time, followed by the tectum and the foot layer,
with the endexhte of varied texture, if present, usually developing just
prior to the appearance of the intine. Outer surface of mature pollen grain
or spore are: (1) perine, (2) exine, and (3) intine. Inner boundary of
sporoderm is in contact with plasma membrane of protoplast.
Systematics and Nomanclature in Palynology
Application of the scientific method to systematic studies requires
ability to deal with abstract concepts. Taxonomy involves systematic
226 Encyclopaedia of Petroleum Science and Engineering
treatment of group concepts that are generalizations and hence
abstractions. The real goal of systematic botany is organization. This
goal should be extended to cover the plant kingdom and to include all
identifiable plants, both fossil and modem. Taxonomy in general depends
on the uniformitarian principle of heredity and evolutionary descent,
regardless of whether the organisms are known to us as modem or as
fossil. All plants, fossil or modem, have had ancestors, i.e., all plants
have been derived phylogenetically back to the point of initial organismal
differentiation. Species consist of populations projected in time.
Commonly the populations are as variable as human beings, because at
any point in time there may be several lines of incipient evolution within
them. Useful taxonomic distinctions must be based on criteria that appear
in historic perspective to have value in classification. Names applied to
plant and animal population should represent recognizable taxa but forms
that integrade between related species should not be ignored.
None of the processes of organization, i.e., classification, taxonomy,
or systematics, depends in any way on nomenclature. Rules that apply
solely to the mechanics of handling names of taxa are given in ''The
International Code of Botanical Nomenclature" (Lanjouw, 1966). Priority
is a most important principle for determining the name of any taxon of a
particular position, rank and circumscription. Circumscription depends
on taxonomic decision, but the nomenclatural decision is automatic and
depends on the date at which verifiable requirements have been met to
entitle a name to legitimate treatment. The Criteria for the legitimacy of
species names thus become the minimum of essential requirements for
validating the name of a species. In nomenclature consideration we need
not enter into the taxonomic problem of whether a taxon deserves
assignment to species rank. Nomenclature involves the philosophy of
precision in scientific communication. The appropriate use of
nomenclature is important. Nomenclatural legitimacy is essential. Fossils
are not now living, but their claim to taxonomic classification is based
on the point of view that they represent, and may be used as a basis for
interpretation of, organisms once living that are comparable to those of
the present day. Plant microfossils, including fossil spores and pollen
and any other determinable microscopic objects, first should be regarded
as the representatives of plants. There are two means of designating and
kind of fossils specimen. One designation indicates its taxonomic position
and the other designates its morphology. A species represents a taxon
of plants. Taxa that deserve to be named obviously should be as
Fundamentals of Palynology 227
consistent in their botanical significance from one group to another as
information permits. Most systematists consider that the only natural
classification in a phylogenetic one. Many indirect types of evidence
may provide evidence of phyletic diversity, e.g., if spores of virtually
identical morphology are genetically related, they are not likely to show
a consistently disjunct stratigraphic occurrence. If spores of somewhat
disjunct stratigraphic occurrence are placed within a common species or
genus, we may reasonably infer that the true stratigraphic range was
probably continuous. All groups of true phyletic relationship have a
continuing stratigraphic range from the time of their inception to the time
of their extinction or diversification. A phyletic approach to taxonomy is
more meaningful. The same functions can be served and virtually similar
morphology can be achieved by different methods of growth. In spite of
functional analogies, the disseminules of different groups differ as much
as they do. There are great differences in the extent of phylogenetic
convergence. The further separated the two convergent lines have
become in ecologic character, the more important it is that convergent
features be recognized.
Some types of spores show long stratigraphic ranges that probably
indicate the continuing existence of a particular group of plants, e.g.,
Tasmanites range in marine environments from Ordovician to Recent.
These microfossils may represent cysts and are only spore like in
morphology. Schizaeaceous spores have ornamentation in which ridges
usually are ornamented by a characteristic tuberculation. Many other
variations have been noted, and several genera have been distinguished
for this reason. Organ genera consist of groups of plants allied within
the same plant family that are defined by functionally related and
commonly connected sets of biocharacters. The families of plants are
based, like other taxa, one classification proposals of competent
systematists. Appropriate familial classification depends on an acute
sense of proportion and judgement, tempered by a reasonable concession
to taxonomic tradition based on previous studies of the group. In
paleobotany general alliance is indicated by discoveries that are still
sometimes spectacular. Although a phylogenetic system is of the greatest
fundamental importance, informal systems based on various kinds of
plant microfossils have been applied successfully for stratigraphic
correlation. Fundamentally, morphologic systems of classification are not
taxonomic. For morphologic purposes convenience governs rather than
priority. Also morphologic systems employ terminology rather than
228 Encyclopaedia of Petroleum Science and Engineering
nomenclature. The week point in the strictly morphologic approach to
plant-microfossil classification lies in its distinct disregard of phylogeny
and phyletic relationship. A clear differentiation between anatomical-
morphological and taxanomic concepts is particularly essential in the
systematic study of fossil plants. In an antificial (special) system of
classification all definable biocharacters are treated very much alike.
Organisms are classified according to resemblance in form. According to
a phyletic system, if there is any reasonable basis for recognizing the
heterogeneous elements, these elements can be separated in taxonomy.
The contrast letween an artificial system of classification and one
reflecting ph logeny is best illustrated by differences in treating
homoplasy, th results of convergent evolution. Taxonomic assignment
should be a means of indicating an author's evaluation of phyletic affinity.
Microfossils still deserve description because they are of use for
purposes of local correlation. Descriptions should be adequate and cover
all of the significant characters. Benson (1943) quoted the thought-
provoking definition of intelligence as "the ability to recognize the
significant elements in a situation."
A cardinal principle of taxonomic organization is the arrangement of
taxa according to what you believe in phyletic ally most probable.
Proposals of taxa have much unstated, so that the reader must work with
minimum information. Formal nomenclature is not designed to reflect
morphologic resemblance. If a scientist is convinced that a proper genetic
(phyletic) alliance exists, he must attempt to be consistant in expressing
this conviction. Because of the inherent variability of biological material,
taxonomy is not an exact science, and for this reason no solutions are
unique. Emphasis should be placed on the personal responsibilities of
scientists who do taxonomic work, i.e., to work according to the spirit of
the Code. A list of those regularly authorized in given in Table 6.
Additional unspecified categories also may be used if needed, provided
that their rt<lative position is made clear. In texonomic study, according
to Knight (1941), "The curious fact is that from a practical viewpoint
one begins best the study of the group with a thorough going survey of
the genetic names already in the literature. One first tries to discover all
the names and, still working only with words, he tries to discover what
species is actually the valid genotype of each name". Much time can be
saved by consulting compilation of names that are generally known as
Fundamentals of Palynology 229
Categories of Taxa, Prescribed Epithets and Terminations, and
Prescribed Suffixes Indlicating Rank
Category Suffix
1. Individuum (represented by specimens)
2 F onna specialis (microparasites)
3. Subfonna
Inadmissible Epithets
4. Fonna "typicus"
5. Subvarietas "original is"
6. Varietas "genuinus"
7. Subspecies "veridicus"
8. Species
9. Subseries
10. Series
11. Subsectio Forbidden
12. Sectio " -oides"; "-opsis";
and prefIX "Eu-"
13. Subgenus
14. Genus
15. Subtribus -inae
16. Tribus -eae
17. Subfamilia -oideae
18. Familia -aceae
19. Subordo -ineae when based on stem of name of a
20. Ordo -ales
l-phYdda. = alga.
21. Subclassis -mycetidae = fungi
-idae = cormophytes
I-PhYC ... = alga.
22. Classis -mycetes = fungi
opsida = cormophytes
230 Encyclopaedia of Petroleum Science and Engineering
Category SuffIX
{-myCOtina ~ fungi
23. Subdivisio -phytina = algae and
{ -myeota ~ fungi
24. Divisio (Phylwn) -phyta = algae and
25. Subregnum
26. Regnum vegetabile
Fundamentals of Palynology 231
Triassic Spores and Pollen
Plants growing in or close to an environment in which deposition is
occurring will have a greater probability of representation than those in
more remote habitats. Large pants with robust leaves and stems will be
favoured over smaller and more perishable ones. The preservation of
fossils spores involves a different series of events and thus of factors
governing the "bias" of representation. The recognition of what parent
plants are represented by successive fossil-spore assemblages is
obviously of first importance in understanding their ecological and
evolutionary meaning. In the Quaternary, and to a lesser extent in the
Tertiary, similarity of fossil spores with living genera is significant enough
that many can be assigned at least to living genera with some degree of
confidence. The only reliable basis for attempting to interpret the earlier
spore assemblages in terms of the parent flora is a study of spores in
situ in more or less contemporaneous fossil plants. Few spore-bearing
lycopod fructifications are known from the Triassic. The spores are
probably giving a fuller picture of the diversity of the group than the
sparse macrofossil record. Some of the genera of spores and pollen that
occur in Triassic rocks have been selected either because of their common
occurrence in the Triassic or because of their particular stratigraphic or
biological significance. The ranges of these genera are shown in Fig. 62.
The approximate equivalence of the stratigraphic units from different parts
of the world is shown in Fig. 63. The stratigraphic equivalence of any
unit is normally that proposed or favoured by the author of the relevant
palynological work. A considerable number of smooth, triradiate
miospores have been reported from the Triassic. Triassic triradiate,
smooth miospores of subtriangular amb, with concave to slightly convex
interradial margins may be properly included in Deltoidospora. Numerous
sculptured, triradiate, azonate spores occur in the Triassic, although
generally they are less abundant ):han in the Carboniferous and Jurassic.
A genus of triradiate, sculptured spores that appears to have a more
limited range is Conbaculatisporites. This includes spores of sub triangular
amb with baculate ornament and is a characteristics Triassic form. Similar
genera of longer range include Baculatispoties with a circular amb which
has fewer and relatively larger sculptural elements. See Fig. 64.
Kraeuselipporites is a common and characteristic genus for triradiate
miospores with a rounded-triangular amb, a broad zona, and a coarse
232 Encyclopaedia of Petroleum Science and Engineering
L .... '
Mkldl, Upper Tr ....
Scyth ... Ants." ladinian Carnian Nonan
- ----1---- ---- - - - - - ~ - - _ + _ - + -
1----1--.--1-4- H.lio"""" ..
1----1----I-- I--'R'::.="::IskA=_=-,,- .. ---l
Fig. 62. Stratigraphic ranges of selected Triassic genera (After Tschudy and
Scott, \969).



AlpIne I
I _
I j
I '"
I 5 8, 17
124, 25 31 I
Rhaetian' Up,*"
("RhiletlC Keuper"
Syst.m"} Df 50,.,.
32, 37, jllUlhOl.

Keuper 1.11
uf lome
!i 26 \ ,3:5
5nl I

, !
1--+---. - - - - - - i-I -----<

i-- - Lene';t0hle 1
! l -------i
H MuSCNlkllk ... :
i c I

." I I

15. 45. 46.
6. 2B. 33, 49.
50, 53, 54, 58
3.4. 29.
34, 35, 56
9, 40, 52
I ' I

H ..... '
, FO''36"on I -,'--

w ... ,,"
South and
East Australl.

Group /\1
I . /Mooroo ....
V" FortNIttOn

formation) ?
'2 /
/ 13
I HawkesburV
I Forrnltlon

1-----1- Sandltonel-- 1--
10. 14 14
AntatctlCol I
lin ""II
- TImber
1-- ....
.... /
16, 22, 23

- 0\ .........
o "
c: 0
o <)
'in rJ)
'0 '"

'" ...




234 Encyclopaedia of Petroleum Science and Engineering
Fig. 64. Triassic triradiate miospores.
Fundamentals of Palynology 235
ornament of coni, principally on the distal face. Heliosporites is a
mono typic genus of somewhat similar spores, with a rather narrower
equatorial feature and longer, blunt, curved, and sometimes recurved
spinose sculptural elements. Zebraspories, a genus characteristic of the
Upper Triassic, is based on triradiate spores with a thin membranous
zona, which is widest interradially and is strengthened by a series of
distal ribs extending on to the zona. Duplexisporites includes spores with
prominent round-topped muri on both proximal and distal surfaces, more
or less paralleling the amb, and interrupted especially toward the distal
pole. Two genera of triradiate spores with a gap between layers of the
exine occur commonly in the Triassic, e.g., Densoisporites, and
Lundbladispora. Other Triassic genera are Aratrisporites and
Saturnisporites. A number of monosaccate pollen genera, some of which
range upward from the Permian, occur in the Triassic. Tsugaepollenites,
a genus characterized by a velum or irregularly attached saccus
reminiscent of the pollen of the living Tsuga, first appears in the Upper
Triassic and is a common constituent of late Mesozoic assemblages. Of
the large number ofbisaccate striate pollen in the Permian relatively few
forms survive into the Triassic. Among Triassic forms at least three
genera may be clearly recognized, e.g., Lueckisporites, Taeniaesporites,
and Striatites. Chordasporites includes nonstraite bisaccate pollen. It
ranges from the Lower Triassic to the Carnian. Aside from Chordasporites
and Ovalipollis there are a large number of less distinctive forms of non-
striate bisaccate genera in Triassic assemblages. The earlier described
bisaccate genus was Pityosporites. Pollen that may be assigned to the
genus Platysaccus, with its pronounced diploxylonoid sacci, occurs all
through the Triassic. Vitreisporites is a genus for small bisaccate pollen.
Gnetaceaepollenites is a genus representing originally prolate spheroidal
grains, with a longitudinally striate exine. One of the most ubiquitous of
all Mesozoic forms is the monocolpate genus Cycadopites. A genus
similar to Cycadopites but readily distinguished from it by its sculpture
is Decussatisporites. Eucommiidites is comparable to Cycadopites in
having one large colpus, but it has in addition two further colpoid
apertures. Classopollis is a genus of remarkable and distinctive
organization. Pollen indistinguishable from Classopollis torosus was
produced by the Rhaetian Conifer Cheirolepidium muensteri. Ricciisporites
is a genus in which the four members of the tetrad are structurally united
by the exine, much as in the pollen of living Ericaceae. Camerosporites is
an Upper Triassic spore of distinctive structure and unknown
236 Encyclopaedia of Petroleum Science and Engineering
relationship. Brodispora is an Upper Triassic genus with an oblate, more
or less spheroidal body marked by a series of concentric striae centring
on the two poles of the spore. Rhaetipollis is a type of spore comparable
to the striate forms just considered in being apparently formed of two
symmetrical hemispheres each with a concentric ornament.
1. Ahrens, Wilhelm, 1958; Die Niederrheinische Braunkohlenformation;
Fortschr. Geologie Rheinland u. Westfalen, Vol. 1-2, pp.763.
2. Barghoom, E.S., and Tyler, S.A., 1965; Microorganisms from the
Gunflint Chest; Science, Vol. 147, pp. 563-577.
3. Benson, Lyman,1943; Goal and methods of systematic botany; Cactus
and Succulent Plant Jour., Vol. 15, pp. 99-1 I I.
4. Bolkhovitina, N.A., 196 I; Fossil and Recent spores of the family
Schizaeaceae; Moscow, Trud. Geol. Inst. Nauk SSSR, Vol. 40,
5. Bunt, J., 1956; Living and fossil pollen from Macquarie Island; Nature,
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6. Butterworth, M.A., 1964b; Miospore distribution in Namurian and
Westphalian; Avanc. Etudes Stratigraphie et Geologic Carbonfere Cong.,
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7. Cookson, I.C. and Pike, K.M., 1954; some dicoty-Iedonous pollen
types from Cainozoic deposits in the Australian region; Australian Jour.
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9. Couper, R.A., 1958; British Mesozoic spores and pollen;
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I I. De Porta, N.S., 196 I; Contribution of Estudio Palinologico del Terciario
de Columbia; Boletin de Geologia, Univ. Ind. de Santander, No.7,
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the Wenlock shales (Silurian) of Wenlock, England; Palaeontology, vol.6,
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13. Downie, Charles, and Sarjeant, w.A.S., 1967; Dinophyceae, pp. 195-
209 in Harland, w.B., and others eds; The fossil record; Geo!. Soc.
Fundamentals of Palynology 237
14. Eisenack, Alfred, 1931; Neue Mikrofossilien des baltischen Silurs, I.:
Palaont. Zeitschr. Vol. 12, pp. 74118.
15. Eisenack, Alfred, 1962; Mitteilungen uber Leiospharen und uber das
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16. Eisenack, Alfred, 1963a; Hystrichospharen; BioI. Rev. Vof. 38, No.1,
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Angiospermen, Berlin.
18. Gleason, H.A., and Cronquist, Arthur, 1964; The natural geography
of plants; Columbia Univ. Press, pp. 420.
19. Groot, J.J., and Groot, c.R., 1962b; Plant microfossils from Aptian,
Albian, and Cenomanian deposits of Portugal; Com Servo Geol. Port.,
XLVI, pp.131-171.
20. Hammen, Th. Van Der, 1954; El Desarrollo de la Flora Colombiana-en
los Periodos Geologicos, I: Maestrichtians hasta Terciariomas Inferior;
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connections during meiosis and pollen development, in Linskens, H.F.
(ed.), Pollen physiology and fertilization; Amsterdam, North-Holland
Publishing Co., pp. 39-47.
24. Hjulstrom, Filip, 1955; Transportation of detritus by moving water,
pp. 5-31 in Trask, P.D., ed; Recent marine sediments-a symposium;
Soc. Econ. Paleontologists and Mineralogists Spec. Pub. 4.
25. Hyde, H.A. and Williams, D.A., 1944; The right word (letter to Paul
B. Sears, dated.July 15, 1944); Pollen Analysis Circular (Oberlin, Ohio,
mimeographed), No.8, pp. 6, October 28, 1944.
26. Jekhowsky,, and Varma, C.P., 1959; Essai de correlation d'apres
cuttings per voie palynologique simplifire dens Ie Tertiare de Mb.2 et
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238 Encyclopaedia of Petroleum Science and Engineering
28. Kedo, GI., 1955; Spores of the Middle Devonian of the northeastern
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29. Knight, IB., 1941; Review of Lang, W.D., Smith, Stanely, and Thomas,
H.D., 1940, Index of Paleozoic coral genera (London, British Mus.
Nat. History); Jour. Paleontology, Vol. 15, No.2, pp. 178-180.
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Tertiar; Palaeontographica, Volo.105, Abl. B, No. 5-6, pp. 125-155.
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33. Lanjouw, J. and others, eds., 1966; International Code of botanical
nomenclature; Utrecht, Netherlands, Internal. Bur. Plant Taxonomy and
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34. Naumova, S.N. 1949; Spores of the Lower Cambrian; Akad. Nauk.
SSSR Izv. Ser. Geol; No.4, pp. 49-56.
35. Naumova, S.N., 1953; Spore-pollen complexes of the Upper Devonian
of the Russian platform and their stratigraphic significance; Trudy Inst.
Geol. Nauk.,Akad., Nauk SSSR, Vo1.143, No. 60, pp. 1-204.
36. Newell, N.D., 1962; Paleontological gaps and geochronology; Jour.
Paleontology, Vol. 36, No.3, pp. 592-610.
37. Newton, E.T., 1875; On "Tasmanite" and Australian "White Coal";
GeoI.Mag., ser. 2, Vol. 2, No.8, pp. 337-342.
38. Nicolaysen, L.O., 1962; Stratigraphic interpretation of ag!!
measurements in southern Africa, pp. 569-598 in Engel, A.E.J., James,
H.L., and Leonard, B.F., eds., Petrologic studies - A volume in honour
of A.F. Buddington; Geol. Soc. America.
39. Ouyang, S., 1964; A preliminary report on sporae dispersae from the
lower Shihhotze series of Hokii district, northwest Shansi; Act.
Palaeontologica Sinica, Vo1.12, No.3, pp. 486-519.
40. Pflug, H.D., 1953; Zur Entstehung und Entwicklung des
angiospermiden Pollens in der Erdgeschichte; Palaeontographica, Vol.
95, Abt. B, No. 4-6, pp. 60-172.
41. Pflung, H.D., 1966; Einige Reste niederer Pflanzen aus dem Algonkium;
Palaeontographica, Vol. 117, Abt. B, Nos. 4-6, pp. 59-74.
Fundamentals of Palynology 239
42. Pokrovskaya, I.M., 1962; Upper Cretaceous and Paleogene spore and
pollen complexes in the European part of the USSR; Pollen et spores,
Vol. 4, No.2, pp. 371-372.
43. Richardson, J.B., 1964; Stratigraphical distribution of some Devonian
and Lower Carboniferous spores; Avanc. Etudes Stratigraphi et
Geologic Carbonifere cong., 5th, Vol. 3, pp. 1111-1114.
44. Richardson, J.B., 1965a; Middle Old Red Sandstone spore assemblages
from the Orcadiam basin, north-east Scotland; ibid., Vol. 7, pt. 4,
pp. 559-605.
45. Rogalska, M., 1962; Spore and pollen grain analysis of Jurassic
sediments in the northern part ofthe Cracow-Wielun cuesta (in Polish);
Inst. Geol. Prace Polska, Vol. 30, pp. 495-507.
46. Simpson, GG1960; Notes on measurement on faunal resemblances
(Bradley volume); Am. Jour. Sci., Vol. 258-A, pp. 300-311.
47. Shaw, A.B. 1964; Time in stratigraphy; New York, McGraw-Hill Book
Co., Inc., pp. 365.
48. Szafer Wladyslaw, 1954; Pliocene flora from the vicinity ofCzorsztyn
(West Carpathians) and its relationship to the Pleistocene; Geol. Prace,
Vol. 11, pp. 238.
49. Tanai, Toshimasa, 1961; Neogene floral change in Japan; Hokkaido
Univ. Fac.Sci. Jour. Ser.4, Geology and Minerology, Vol. 11, No.2,
pp. 119-398.
50. Timofeyev, B. V., 1959; Ancient flora of the Baltic region and its
stratigraphic significance, Vses, Nett. Nauchno-Issled. Geol.-Razved.
Inst. Trudy, Vol. 129, p. 320.
51. Timofeyev, B.V., 1959; Ancient flora of the Baltic region and its
stratigraphic significance; Vses. Nett. Naucho-Issled. Geol.-Razved Inst.
Trudy, Vol. 129, pp. 320.
52. Tschudy, R.H., and Scott, R.A., 1969; Aspects of Palynology; John
Wiley & Sons, Inc., New York, pp. 510.
53. White, D., 1929; The flora ofthe Hermit shale, Grand Canyon, Arizona;
Carnegie Inst. Washington Publ. 405, pp. 221.
54. Wodehouse, R.P., 1935; Pollen grains, New York, McGraw-Hili Book
Co., Inc.
55. Woods, R.D., 1955; Spores and pollen - a new stratigraphic tool for
the oil industry; Micropaleontology, Vol. I, No.4, pp. 368-375.
240 Encyclopaedia of Petroleum Science and Engineering
References of Figures of Plates
I. Cousminer, H.L., 1961; Palynology, Paleofloras, and
Paleoenvironments; Micropaleontology, Vol. 7, No.3, pp. 365-368.
2. Garrels, R.M., 1960; Mineral equilibria-At low temperature and
pressure; Harper & Brothers, New York, pp. 254.
3. Kedves, M. 1960; Etudes Palynologiques dans Ie Bassin de Dorog I;
Pollen et Spores, Vol. 2, No.1, pp. 89-18.
4. Ma Khin Sein, 1961 a; Palynology of the London Clay; Ph.D. Thesis,
University College, London.
5. Tschudy R.H., and Scott, R.A., 1969; Aspeats of Palynology; John
6. Winslow, M.R., 1959; Upper Mississippian and Pennsylvanian
megaspores and other plant microfossils from Illinois; Illinois Geol.
Survey Bull. 86, pp.135.
Diversity is the rule of the nature. There exista wide array of species
of micro-organisms, plants and animals which differ with each other in
structure, function and behaviour and which have' occupied almost all
ecological niches existing on the planet earth (viz., in its annosphere,
hydrosphere, and lithospere). Out of this preponderant diversity ofliving
beings have emerged two overriding themes or concepts which give unity
to the sciences of life and throw light upon them all. Out of these two
unifying concepts or principles of modem biology, one is the concept of
organization. This tells us that at every level, from the molecule through
the supra-molecular organelle, the cell, the tissue, the organism, the
individual, and upto the population or the society, the properties of life
depend only to a small degree upon the substances of which living matter
is composed. To a much greater degree living things owe their nature to
the way in which the components are organized into orderly patterns,
which are far more permanent than the substances themselves. The other
unifying concept of modem biology is that of the continuity of life
through heredity and evolution. This tells us that organisms resemble
each other because they have received some common ancestor hereditary
elements, chiefly the chromosomes of their nuclei, which are alike both
in respect to the substances which they contain and the way in which
these substances are organized. When related kinds of organisms differ
from each other, this means that in the separate lines of descent from
their common ancestor changes in the hereditary elements have taken
place, and these changes have become established in whole populations.
Fundamentals of Evolution
Evolution is the development of organisms through time. The term
evolution (Latin, evolution - an unfolding or unrolling) means a gradual
orderly change from one condition to another. There are ample geological
evidences which suggest that the planets and stars, the earth's
topography, the chemical compounds of the universe, and even the
chemical elements and their subatomic particles, have undergone gradual,
242 Encyclopaedia of Petroleum Science and Engineering
orderly changes during the long history of the universe. This kind of
evolution which includes evolution from atoms molecules to simple and
then complex substances, and from these to still more complex ones
capable of self-duplication, has been termed as inorganic or chemical or
molecular evolution. The most significant outcomes of chemical evolution
are the origin of biologically important macromolecules (viz., proteins and
nucleic acids-DNA and RNA), origin of life and an environment to sustain
life on the planent earth. Further, it is biologically evident that all the
various prokarytes and eukaryotes (viz., viruses, bacteria, plants and
animals) existing on the earth at the present time have descended from
other, usually simpler organisms by gradual modification s which have
accumulated in successive generations. This kind of evolution is started
from the culmination point of chemical evolution into the origin of life,
and still is in process and is called biological or organic evolution. Thus,
the concept of organic evolution holds that all the varied kinds of
animals and plants which now known have developed out of earlier
types by completely natural changes during the passage of time.
The branch of biology which incorporates in it, the studies
concerning the problems of chemical evolution and origin of life and
organic evolution and origin of man and other present day organismal
spceies of planent earth is called evolutionary biology.
The concept of evolution is based on detailed comparisons of the
structures of living and fossil forms, on the sequences of appearances
and extinction of species in past ages, on the physiological and
biochemical similarites and differences between species and an analysis
of the genetic constitution of present day plants and animals. It is an
indubitable fact which has been accepted by all but one or two of those
who are accredited experts in the study of biology. Yet as a scientific
theory, evolution cannot really be said to have begun until about 1800,
and it was not definitely established until the decades after 1859, the
year when Charles Darwin published "On the origin of species" a master
work which laid down the principles of evolution in a form which they
are still largely accepted.
Though much knowledge has been gained about the different
evolutionary processes during post-Darwinian phase, yet our knowledge
is far from complete. Much remains to be discovered, much is to be
learned. The applications of new techniques, such as the use of high-
speed digital computers, and the application of comparative biochemistry
Appendix 243
to elucidate developmental pathways or to discover evolutionary
relationships at the chemical level (viz., chemotaxonomy) promise to open
grand new vistas in the field of evolutionary biology.
Characteristics of Evolution
Evolution includes following characteristics:
1. Basically evolution is the result of the differential survival in
each generation of the progeny of individuals with certain
special characteristics. In tum these adaptive characteristics
that in part account for the differential survival.
2. Mechanism of inheritance is the foremost important element
which plays an important role in evolution. The ways in which
genes determine the expression of characters in an organism
and the manner in which genes are transmitted to offspring,
shape the whole evolutionary picture. Evolution is often
defmed, and quite rightly, so, as changes in the frequency of
genes in a population. In tum the organization of genes in
chromosomes and the behaviour of these during cell division
affect the mechanisms of inheritance and evolution.
3. Normally sexual reproduction has far much evolutionary
significance than asexual reproduction. Sexual reproduction is
a mechanism that tends to combine the genetic materials of
individuals and produce new and novel combinations. Its effect
is a tremendous increase in variability, and the advantages of
this are so great that the phenomenon has become almost
universal in all plants and animals. Sexuality apparently
developed very early in the evolutionary history of organisms.
4. Without sexuality and interbreeding, species as we know them
today would not exist. But just as important for the evolution,
particularly the multiplication of species has been the
development of barriers (viz., isolating mechanisms) to the free
exchange of genes, be they geographical, ecological,
behavioral, or genetical. The very simple earliest organisms may
have been able to mix their genes with others of the same level
of organization, but present-day organisms, with elaborate and
complicated developmental pathways, cannot exchange genes
with drastically different organisms. When they do the result
of these exchanges is lethality or at best steriligy. The selective
244 Encyclopaedia of Petroleum Science and Engineering
advantage of barriers that prevent gene exchange in such
instances is obvious.
5. In a slightly different sense, it also can be said that evolution
is shaped by environment. Differential survival is always partly
due to capacity to adopt to the environment, particularly the
physical environment. Chemical evolution could occur only
after our planet changed from the original "ball of fire" to a
body where water could accumulate. Organic evolution, which
has produced the tremendous number of organisms, is in part
a consequence of the adaptation of these organisms to the
infinite types of environments found on earth.
Thus, the evolution is the result of the interplay of many and diverse
factors. These factors are themselves subjected to change. Early in the
history of each lineage of plants and animals, structures or processes
have developed which have profoundly influenced the evolutionary
history of that group. So, for example, a segmented body and an
exoskeleton have been major factors in the success of the insects, but in
turn these same factors have restricted the size and habits of the members
of the class Insecta.
Significance of Evolutionary Biology
The theory of evolution is quite rightly called the greatest unifying
theory in biology. The diversity of organisms, similarities and differences
between kinds of organisms, patterns of distribution and behaviour,
adaptation and interaction, all this was merely a bewildering chaos of
biology in which that theory does not serve as an ordering principle. On
the contrary, genetics, morphology, biogeography, systematics,
planentology, embryology, physiology and other branches of biology,
all have illuminated some special aspect of evolution and have
contributed to the total explanation where other special fields failed. In
many branches of biology, one can become a leader even though one's
knowledge is essentially confined to an exceedingly limited area. This is
unthinkable in evolutionary biology. A specialist can make valuable
contributions to special aspects of the evolutionary theory, but
only he who is well versed in most of the branches of biology listed
above can present a balanced picture of evolution as a whole. Whenever
a narrow specialist has tried to develop a new theory of evolution, he
has failed.
Darwinian evolution pennits two general predictions----(i) if there were
an evolution from simple forms to more complexones, there must be certain
structural, devlopmental and chemical similarities between different forms
of life, and (2) there must be a means by which variation in populations
arise, and are transmitted from generation to generation. This chapter
will deal only with the evidences that have been found to support the
idea of a relationship between existing organisms and also of a
relationship between extinct and existing organisms, while certain
forthcoming chapters will deal with the way in which change can initiate
and bring about an evolutionary process such as that proposed by
the evidence that organic evolution has occurred is so over-
whelming that no one who is acquainted with it has any doubt that new
species are derived from previously existing one by descent with
modification. The fossil record (palaeontology) provides direct evidence
of organic evolution and gives the details of the evolutionary
relationships of many lines of descent, while different biological
disciplines like comparative anatomy, taxonomy, embryology, physiology,
biochemistry, genetics and biogeography provide indirect evidence, in
support of biological evolution. All of these direct and indirect evidences
for biological evolution can be discussed.
I. Palaeontological Evidences
The science of palaeontology which deals with the finding,
cataloguing and interpretation of fossil remains of ancient plants and
animals, has aided immensely in our understanding of the lines of descent
of many invertebrate and vertebrate animals and certain Protista,
Bryophyta and Tracheophyta plants. A Fossil (Latinfossilium, something
dug up) is some evidence of animals or plant which is seen in the stratum
layers of earth's crust and which lived a long time ago. Thus, the fossils
246 Encyclopaedia of Petroleum Science and Engineering
not only include the bones, shells teeth and other hard parts of an animal
body which may survive, but also any impression or trace left by previous
Kind of Fossilization
In the main, the hard parts of organisms (teeth, skeletal parts and
shells) are preserved as fossils. In some of these fossils, the original hard
parts or more rarely the soft tissues of the body, have been replaced by
minerals, a process called petrifaction. Iron pyrites, silica and calcium
carbonate are some of the common petrifying minerals. For example, the
petrified muscle of a shark more than 300,000,000 years old was so well
preserved by petrifaction that not only individual muscle fibres, but even
their cross striations, could be observed in thin sections under the
microscope. However some animals are preserved without petrifaction
but with little or no change from the time of death. For example, a Russian
worker described the finding of a frozen mammoth (an extinct form related
to elephants) in Siberia. It was estimated that the animal had been
preserved in frozen state for approximately 25,000 years, yet the flesh
was so well preserved that it could be, and was eaten by dogs. Further,
numerous specimens of insects, spiders, and mites have been found
preserved in amber in the Baltic region of Europe. During the Oligocene
period, about 38 million years ago, Northern Europe was covered with
coniferous forests (forests of gymnosperms) The trees in these forests
exuded a sticky resin that trapped the spiders, mites and insects. The
resin ultimately hardened into amber, with the arthropods embedded in
it. In some cases the preservation is so good that the colours have not
been changed. Land animals occasionally have been covered with wind-
blown sand or volcanic ash, or have been trapped in bogs, quicksand or
asphalt pits, and their hard parts have been preserved.
Footprints or trails made in soft mud, which subsequently hardened,
are a common type of fossil. For example, the tracks of an amphibian
from the pennsylvanian period, disvovered in 1948 near Pittsburgh,
revealed that the animal moved by hopping rather than by walking, for
the footprints lay opposite each other in pairs.
Still other fossils are in the form of molds and casts, both of which
are superficially similar to pertified fossils but are produced in a different
way. Molds are formed by the hardening of the material surrounding a
buried organism, followed by the decay and removal of body of the
organism. The mold may subsequently be filled by minerals which harden
to form caste which are exact replicas of the original structure.
Appendix 247
Conditions for fossilization- The formation and preservation of a
fossil require that some structure be hard and be buried immediately. It
should be clear that when a dead animal or plant is left exposed, it soon
disappears as the result of the activity of scavengers and the bacteria
and fungi of decay. Even the bones of horses and cattle that die on the
!plain soon disappear. The chance of any exposed organism becoming
fossilized is very slight indeed. Immediate burial is a prerequiste to the
process of fossilization; by far the most conunon kind of burial favourable
for fossilization is that provided by water-borne sedimentary rocks.
Fonnation of Rocks
Geologists envision the earth's crust as having gone through a series
of changes involving the alterations ofland masses by glacier movements
or land shifts that resulted in the rise of mountain ranges, and the levelling
of other land when one land mass came to rest upon another, the
tremendous pressure is exerted, and the lack of available water, caused
the conversion of the original land mass into rock strata. Through the
geological ages, then, land mass over land mass formed layers of rock
strata, each of which had at some time, been exposed to the atmospheric
environment. The lowest strata solidified some two to three billion years
The rock strata of earth includes sedimentary and igneous rocks,
the formation of both of which is remain significant in the process of
fossilization. To understand the nature of the formation of sedimentary
rocks, one must take into account certain natural processes that are
occurring in the world today and that have been occurring since the crust
of the earth was formed. By the process of erosion, through the action
of wind and rain, and of freezing and thawing, rocks are gradually broken
into the small particles that form soil. Through the action of rain, the
particles of the soil are carried into streams and rivers and ultimately into
lakes or oceans. This sedimentary material carries with it the bodies of
many aquatic organisms and also the bodies of terrestrial forms that
happen to be swept along by the streams and rivers. The hard parts of
some of these organisms may be preserved, and in the course of time
the sedimentary deposit, owing to the pressure of water above it and
also to chemical reactions, is converted into sedimentary rock. The nature
of the sedimentary material determines the kind of sedimentary rock
formed-limestone, sandstone, and shale are familiar kinds. The method
of formation of sedimentary rocks clearly distinguishes them from igneous
248 Encyclopaedia of Petroleum Science and Engineering
rocks, which were formed by the solidification of moltern material when
the earth cooled, and are being formed by cooling of magma expelled
from active volcanoes.
Another natural processes called submergence and emergence have
occurred in the past and are still occurring between land and sea. Slow
and gradual changes in level between land and sea are now in process.
For instance, it is now recognized that the land on the eastern coast of
United States is gradually sinking into the sea, where as the land on the
Pacific coast is gradually rising. The sinking of the land below the sea is
called submergence, and the rising of land above the sea is called
emergence. In the geologic past, many regions of the earth have
undergone a series of submergences and emergences. As a consequence,
in many places (e.g., Strata of Gand Cranyon of the Colorado), a whole
series of different layers of sedimentary rocks is found.
Further, the law of superposition of Geology states that the deepest
layer of earth strata were deposited first and other layers in succession
at later periods of time. Consequently, more superficially located fossils
will be considered to be of recent origin. Moreover, if each formed layer
of rock were left undisturbed until another layer was deposited on top
of it, one would have perf acts series for the study of fossil forms. The
rock record of the earth, however, is not so complete. Layers deposited
under water can emerge as land and be partially or completely eroded
away. If a new submergence then occurs and a new layer of sedimentary
rock is formed, there will be an unconformity between the two strata.
This lack of sequence between layers makes the study and identification
of strata difficult. Also, fossils that were formed may be destroyed in the
formation of metamorphic rocks. As a result of great pressure and heat,
deep layers may melt. When this material later solidifies again, the fossils
originally present will usually be lost. Limestone is a form of sedimentary
rock rich in fossils, when limestone melts and crystallizes into
metamorphic rock, the result is marble. Despite the paucity of fossil
formation and destruction of fossils by several reasons, the story of
rocks is a very convincing one with reference to evolution.
Determination of Age of Rocks and Fossils
In the past, geologists and palaeontologists were able to make fairly
accurate estimations of the age of different rock strata and their fossil
record by using the known rate of the accumulation of salt in the oceans.
Presently, rock deposits are dated largely by taking advantage of the
fact that certain radioactive elements are transformed into other elements
at rates which are slow and essentially unaffected by the pressures and
Appendix 249
temperature to which the rock has been subjected. For example, geologists
standardly use uranium dating to estimate the time of solidification of
rock. Radioactive uranium decays spontaneously to lead. The half-life
of uranium is about 4,500,000,000 years.
Since the uranium of the earth was formed four to five billion years
ago when the great pressure of a contracting dust cloud created
thermonuclear heat, why should not all uranium measurement give the
same age, four to five billion years? The answer lies in the difference
between the radioactive decay in a solid and in a liquid. In a liquid, the
uranium is diluted, washed away, etc. But when liquid solidifies, the
uranium it contains is not free to move, and undergoes its decay into
lead in a highly localized region. The ratio of uranium to its stable product,
lead, indicates the time of solidification of the liquid material and,
therefore, the time at which it was added to the earth's crust.
For the determination of the age of fossils, other radioactive materials
are analyzed. Radioactive carbon (C
) is a natural radioactive form,
produced in the atmosphere from the contact of naturally occurring C12
with UV light. It passes down as C
and enters plants and then animal
material. The ratio of C
to C
remains constant during life, because of
the constant interaction of biological organisms with the environment.
Upon death and fossilization, this ratio decreases as the Cl4 undergoes
decay. It is possible therefore, to determine when the fossilized individual
lived by comparing its present C
to C
ratio with that usually maintained
during life. Radioactive carbon has a half-life of about 5,568 30 years,
and can only be measured upto 25,000 years or about 5 half-lives. This
limitation results because the amount of C
in organisms is so small to
begin with. Radioactive-carbon dating is excellent for the anthropological
studies of early tribal civilizations, but not for the earlier strata.
Recently, the transformation of radioactive potassium (0) to argon
and rubidium to strontium has been used in a similar way for dating fossil-
bearing rocks of any age and type. K
has a half-life of 1-3 billion years.
Also because of its greater concentration in most rocks, it is more
accurate method of dating fossils than uranium, a relatively rare element.
A bed of pre human fossils in South Africa dated by rock composition
gave a result of 500,000 years, whereas radioactive potassium dating
method indicated an age of 1,750,000 years-a most important difference,
considering the nature of the fossils.
250 Encyclopaedia of Petroleum Science and Engineering
Relatively short periods of geologic time are estimated by measuring
the rate at which waterfalls recede upstream as they wear away the rocks
over which they tumble or by counting the annual deposits of clay on
the bottom of ponds and lakes.
The Geological Time Table
Geologists, as a result of their studies of the strata of sedimentary
rocks in the different regions of the world, have classified geologic history
into six eras. The oldest era with fossils is the Archeozoic (era of primitive
life) and this is followed in turn by the Proterozoic (era of early life), the
Paleozoic (era of ancient life), the Mesozoic (era of medieval life ), and
the Cenozoic (era of modem life). The Paleozoic, Mesozoic, and Cenozoic
eras are divided into periods and the periods of the Cenozoic into epochs.
There is evidence that between the different eras there were wide-spread
geologic disturbances, called revolutions which raised or lowered vast
regions of the earth's surface and created or eliminated shallow is land
seas. These revolutions produced great changes in the distribution of
sea and land organisms and wiped out many of the previous forms of
life. For instance, the Paleozoic era ended with the revolution that raised
the Appalachian mountain and it is believed, killed all but 3 per cent of
the forms of life existing them. The Rocky mountain revolution (which
raised the Andes, Alps and Himalayas as well as the Rockies) annihilated
most reptiles of the Mesozoic. Following table of geologic time-table
shows the eras and some of their subdivisions, the approximate duration
of each era, some of the important geological features, and the
characteristic animals and plants (see Table 1).
Conclusions Drawn from Fossil Record
The most important features of the fossil record which is tabulated
in the following table can be summarized as follows:
(i) There existed a multitude of diversified animal groups, similar
to the animal groups that exist today.
(iI) All fossils did not appear at a time, but appeared during different
great spans of times, and
(iii) The most primitive forms of life are found in the oldest rocks.
(iv) Moving up through the various strata, from older to more recent
formations, there is a succession of higher and more complex
forms of life (geologic succession).
Appendix 251
(v) In many instances, a group arose in one period or era and
remained scarce, but in the next period or era it became
dominant after undergoing adaptive radiation.
(vi) There have been many extinction of large groups, but after the
establishment of all major phyla, some species of each phylum
have persisted down to the present.
(vii) None of the past forms oflife are exactly like any of those now
MillIOn .. of year .. ago
Table-I: Geological time-table
GeologIcal feature
End oflast ice age;
climate wanner.
Repeated glacia-
tion; four ice ages
Climate wann in
the beginnmg but
gradually cooling.
formation of Alps
and Himalayas.
Decline of woody plants;
rise of herbaceous ones.
Great extinction of species.
Development and spread of
modem flowering plants
Rise of grasses and of
Arthropods and
molluscs most
abundant. Appear-
ance of modem
invertebrates type.
Rocky Mountain Revolution (Little destruction of fossils)
Great swamps in
early part, Rocky
Mountain and
Andes fonned.
Continents fairly
high, shallow seas
over some of
Europe and was-
Rapid development of
angiosperms (first mono-
cotyledons), gymnosperms
Increase of dicotyledons;
conifers and cycads domi
Extinction of
ammonites, spread
of insects.
Maximum of
annnonites. Insects
abundant, includ-
ing social insects.
Vertebrate ..
Age of man
Extinction of
great mammals;
first human
social life.
Archaic mam-
mals declined
after Eocene.
mals evolved
in the latter
epochs. Rise
of anthropoids
Extinction of
drnosaurs and
toothed birds;
rise of primitive
Dominance of
dinosaurs, first
toothed birds;
early mammals.
Millums of years ago
Eras PerIOd., Epoch., Geologlcal.feature Plants Invertebrate., Vertebrates (\)
Tnassic Chmate wann : Spread of cycads and coni- Limulus present; First dinosaurs ~ .
(230) great desert areas. fers; seeds ferns disappear. Marine inverteb- Mammal-like
rates decline in repitiles.
Appalachian Revolution (some loss of fossils)
PaleozOIc Permam Appalachians and First cycads and conifiels; Last of trilobites; Expansion of
(600) (280) Urals formed. decline of lycopods and expansion of reptiles. mam-
Glaciation and horse tails. ammonites; mal-like rep-
aridity. modem insects tiles arose
Pennsyl- Mountain build- Great forests of seeds ferns Insect common: First rephles,
vanian ing. Great coal and gymnosperms. first insects spread of ancl-
(320) swamps. fossils. ent amphibians
Mississi- Wann humid cli- Lycopsids, horsetails, and Culmination of Spread of
ppian mate. Shallow seed ferns dominant First crinoids sharks. Rise
(345) island seas. coal deposits. (echinoderms) of amphibians.
Devonian Emergence of First forests, lands plants Brachiopods flou- First mphibi-
(405) land; some and well established, first rishing; decline of aus Rise of
regions and gla- gymnosperms. trilobites. fishes-Iung-
cation. fishes shad< abundant.
Silurian Extensive conti- First definite eVidence of Corals, brachio- Rise of ostra-
(425) nental seas; low- land plants, algae domi- pods, eurypterids. codems (primi-
lands increasingly nant. Marine arachnids tlVe fines)
arid as land rose. dominant; first
(wingless) msects.
MIllIOns of years ago
PerIOd. Hpochs
GeologIcal jeature Plants Invertebrales
Great submerge- Manne alage abundant. Trilobite abund-
ence of land; ant; diversified
warm climates molluscs
even 10 Arctic.
Lands low, climate Algae, especially manne Tnlobltes, brachio-
mIld; earliest rocks forms. pods dominant;
with abundant all phyla repre-
fossils sented.
Second Great Revolution (Considerable loss of fossils)
Great sedimenta-
tion; volcamc acti-
vity later; exten-
sIve erosion, repea-
ted glaciations.
Few fissils (sponges, radio-
larian ptutozoans, worm
burrows and algae). Thallo-
phyta evolved. F ossiIs of
blue green algae.
First Great Revolution (Considerable loss offossils)
Great volcanic
activities; some
depOSItIon; exten-
sive erosion soeks
mostly igneous or
Ongm of earth.
Igneous rocks.
Indirect evidence of bfe
from graphite and lime-
stone, but no recognizable
fossils except bacteria,
Organic matenal found m
rock, origin of life.
Most mvertebrate
phyla probably
Numbers given in parentheses indIcate approxImate time since beginning of era period or epoch.
First verteb-
rates armored
Appendix 255
All these significant aspects of fossil records substantiate the
Darwins theory of evolution by showing the increasing complexity of
organismal structures with time. Besides many other interesting features,
the fossil record helps in drawing correct conclusions about the possible
origin of certain modern vertebrates (birds and horse).
Basically, evolution is a biochemical phenomenon and it is, therefore,
natural that physiology and biochemistry have given some of the
following most important and dependable evidences to suport the idea
of evolution.
1. Protoplasm Chemistry
Biochemical analysis of the living matter, in the protoplasm which is
considered as "the physical basis oflife", suggests that protoplasm from
a variety of sources (i.e., bacteria, blue green algae, plants and animals)
has the same biochemical constitution. It mainly consists of substances
like proteins, lipids, carbohydrates, water, etc. This would suggest that
during evolution the most fundamental property of living things has
remained intact, while variations in certain essential respects produced
the variability according to the needs of differential forms.
2. Chromosome Chemistry
Like protoplasm, another remarkable similarity at the biochemical level
is found in the chemistry of chromosomes. The chromosomes of all living
organisms basically consist of nucleic acids (DNA, and RNA) and
proteins (histones and protarnines). The molecules of these chemical
substances remain arranged in all chromosomes in, a almost identical
fashion. Such a uniformity in the composition of chromosome again
suggests a common origin of most living beings.
3. Enzyme Similarities
A large number of animals and plants contain identical enzymes.
Several enzymes found in the digestive tract are common in a variety of
animals. For example, trypsin and amylase are found from sponges to
mammals. A number of enzymes used in photosynthesis are common in
a variety of green plants. Such common enzymes and consequently a
common mechanism of process of photosynthesis suggest a common
ancestry of green plants.
256 Encyclopaedia of Petroleum Science and Engineering
4. Hormonal Similarities
Like enzymes, hormonal similarities are also found in all vertebrates.
For example, thyroid hormone is commonly found in all vertebrates and
this hormone from one class of organism can be substituted for that in
another class of organisms. For example, in frogs deficiency of thyroid
hormone can be corrected by feeding them on mammalian thyroid tissues.
Likewise, another commonly occurring hormone of verterbrates is
melanophore expanding hormone. It is concerned with the pigmentation
of the skin to expand, thus, rendering the skin colour dark. This hormone
is found in amphibians and mammals. In the latter it is a vestigial hormone,
but if it is grafted into the amphibian skin, the skin pigmentation expands.
The presence of these hormones in vertebrates is understandable only
on the basis of descent from an ancestor to which these hormones were
5. Comparative Serology
When a foreign protein is inoculated into the blood of an animal,
the latter produces a complex protein compound against that foreign
protein inoculated. These compounds are familiarly known as anti-bodies
and the foreign inoculated protein is known as antigen. When a reaction
occurs between antibody and antigen, a soft white precipitate will be
formed. The strength of precipitate depends upon the concentration of
antigen. The precipitate is the precipitin and the test is precipitation test.
One of the remarkable features of this test is, that the antibodies formed,
against one antigen, can also react with antigens of other source,
provided the latter is chemically similar to the first antigen. Antibodies
containing serum is known as antiserum. Antiserum of antigen of an
animal can be tested with antigens of other animals in order to show
their relationships. The test can be interpreted that if precipitate results
with more diluted antigen of one animal against the test animal, then the
former is more closely related to the latter; if precipitate results with less
diluted antigen of that animal, then it is distantly related to the test animal.
Such precipitin tests have conducted to resolve the disputed
relationships of organisms, in recent years. Of scores of examples, here
we give two illustrations.
Till recently, it is believed that whales have relationship with fishes.
It is because, almost all of their anatomy are so strongly modified to
aquatic fish-like life. Only few anatomical clues to show their relationships
to other mammals, remained. However comparative serology of whales
with other mammalian groups indicates that their serum proteins are most
like those of the even-toed hoofed (Order Artiodactyla) mammals. This
might suggest that whales sprang from primitive artiodactyl stock.
Human .l!(um ----W.
Rabbit serum
antiserum containing
antibodies eo_inst
human serum
placed in
each tube
Fig. 1. Principle of preciptin test applied to investigation of animal relationship.
The same serological tests when performed in slightly modified form
among the members of primates-man, an anthropoid ape, an old world-
monkey, a new world-monkey and a lemur, the amount of precipitate of
serum proteins would decrease in descending order, that is, the
anthropoid ape is more closely related to man than other organisms. Even
among anthropoid primates, tests done according to onchterlony
technique. reveal that the serum proteins of chimpanzee are more alike
to man's serum proteins than the serum proteins of asiatic apes, gorilla
and baboon.
258 Encyclopaedia of Petroleum Science and Engineering
Similar comparative serological tests reveal the fact that cats, dogs,
and bears are closely related. Cows, sheep, goats, dear and antelopes
constitute another closely related groups in terms of "blood relations."
Serological tests also suggestes that there is a closer relationship among
the modem birds than among the mammals, for all of the several hundred
species of birds tested give strong and immediate reactions with serum
containing antibodies for chicken serum. From other tests it was
'SIIoop serum
. .' '
1 2 3 4 5 6 7 B 9 10
Fig. 2. Principle of precipitin test employing serial dilutions of
antigen and the interfacial reaction.
concluded that birds are more closely related to the. crocodile line of
reptiles than to the snake-lizard line, which corroborates the
palaeontological evidence. Similar tests of the sera of crustaceans, insects
and molluscs have shown that forms regarded as being closely related
from porphologic and palaeontologic evidence also show similarities in
their serum proteins.
6. Amino-Acid Sequence Analyses
Molecular biological investigations of the sequence of amino acids
in the a and chains ofhaemoglobins from differents species have revealed
Appendix 259
great similarities, of course, and specific differences, the pattern of which
demonstrates the order in which the underlying mutations, the changes
in nucleotide base pairs, must have occurred in evolution. The
evolutionary relationships inferred from these studies agree completely
with those based on morphologic studies. Analyses of the amino acid
sequence in the protein portion of the cytochrome enzyme provide further
concurring evolutionary relationships. Further the pattern and rates of
reactions of lactate dehydrogenase and certain other enzymes with the
normal pyridine nucleotide coenzyme (NAD) and with analogoues ofNAD
can be used to demonstrate evolutionary relationships.
7. Excretory Product Analyses
An analysis of the urinary wastes of different species provides the
evidence of evolutionary relationship. The kind of nitrogenous excretory
waste depends upon the particular kinds of enzymes present, and the
enzymes are determined by genes, which have been selected in the course
of evolution. The waste products of the metabolism of purines, adenine
and guanine, are excreted by man and other primates as uric acid, by
other manunals as allantoin, by amphibians and most fishes as urea, and
by most invertebrates as ammonia. Vertebrate evolution has been marked
by the successive loss of enzymes for the stepwise degradation of uric
acid. J. Needham made the interesting observation that the chick embryo
in the early stages of development excretes ammonia, later it excretes
urea and finally it excretes uric acid. The enzyme uricase, which catalyzes
the first step in the degradation of uric acid, is present in the early chick
embryo but disappears in the later stages of development. The adult frog
excretes urea, but its tadpole larva excretes ammonia. These biochemical
examples are the repetition of the principle of recapitulation.
S. Pbospbageus
The phosphagens playa key role in muscle contraction and are the
sources of energy for the resynthesis of ATP, once they are broken-down.
In the muscles of most vertebrates, phosphagen is always a specific
compound called creatine phosphate, while in most invertebrates it is
arginine phosphate. Hemichordates, the most primitive chordates, have
both the phosphagens, the creatine phosphate as well as argine
phosphate such a situation is also found in echinoderms and on
morphological grounds echinoderms have been considered close to the
ancestor of chordates.
260 Encyclopaedia of Petroleum Science and Engineering
Another type of evidence that indicates that all forms of life are
related comes form the cellular level. The very fact that the cell is the
unit of structure for all living organisms (except viruses) is thought to
reflect the basic relationship among living forms. This relationship is even
further emphasized by the fact that it has been possible for biologists to
construct a picture of the "generalized" cell from which all other types
can be inferred.
Moreover, all cells that have been examined thus far have a DNA-
RNA-protein information and communication system All forms contain
membranes that are made up of double-layered lipoproteins. All cells
(except few bacteria) utilize the glycolytic pathway. Most bacterial forms,
and all uni- and multicellular organisms, have a Krebs cycle and an
electron transport system. All are based on ATP as an energy donor.
Certainly these factors provide an overwhelming demonstration of the
interrelatedness of biological forms.
Genetics, the science of heredity, deals the variability of plants and
animals. Hereditary variations provide the raw material of evolution. There
are mainly two sources of hereditary variations namely, recombination
and mutation. While recombinations, after hybridization yield new
combinations, mutations will create new genetic material which never
existed earlier.
For the past several thousand years man has been selecting and
breeding (i.e., hybridizing) animals and plants for his own uses, and a
great many varieties, adapted for different purposes, have been
established. These results of artificial selection provide striking models
of what may be accomplished by natural selection. All of our breeds of
dogs have descended from one, or perhaps a very few, species of wild
dog or wolf, yet they vary so much, in colour, size and body proportions
that if they occurred in the wild they would undoubtedly be considered
separate species. They are all interfertile and are known to come from
common ancestors, so they are regarded as varieties of a single species.
A comparable range of varieties has been produced by artificial selection
in cats, chickens, sheep, cattle and horses. Plant breeders have
established by selective breeding a terrnandous variety of plants. From
the cliff cabbage, which still grows wild in Europe, have come cultivated
cabbage, cauliflower, Kohlrabi, Brussels, sprouts, brocoli and kale.
Appendix 261
Further, cytogeneticists have been able to trace the ancestry of
certain modem plants by a combination of cytologic techniques in which
the morphology of the chromosomes is compared and by breeding
techniques which compare the kinds of genes and their order in particular
chromosomes in a series of plants. In this way, the present cultivated to
bacco plant, Nicotiana tabacum, was shown to have risen from two
species of wild tobacco, and com was traced to teosinte, a grass-like
plant which grows wild in the Andes and Mexico. Moreover, the cytologic
details of the structure of the gaint chromosomes of the salivary glands
of fruit flies have been of prime importance in unrevealling the
evolutionary history of many species of Drosophila.
Mutations have also played a very significant role in evolution.
Different kinds of mutations-namely gross mutation due to variation in
chromosome number (polyploidy and aneuploidy), and point mutations
(see chapter of mutation) introduce different kinds of variations in plants
and animals and consequently result in speciation. Plant breeders have
employed induced polyploidy methods in producing numerous
economically important varieties of plants. Geneticists have produced
many new strains of micro-organisms, plants and animals (Drosophila)
by artificially inducing point mutations in them
Thus, the artificial selection methods due to recombination or
polyploidy and induced methods of mutations have suggested the
fundamental processes which may be involved in organic evolution.
Bio-geography deals with the manner in which plants and animals
are distributed over our planet. On the basis of similarities in the existing
fauna, found in different regions of the earth, following six bio-
geographical regions have been distinguished :
(a) Nearctic- North America down to ~ e Maxican Plateau.
(b) Palearctic- Asia North of the Himalayas, Europe and Africa,
North of Sahara Desert.
(c) Neotropical- Central South of America.
(d) Oriental- Asia, south of Himalayas.
(e) Ethiopian- Africa, south of Himalayas.
(d) Australian- Australia and associated islands.
. ",.
- - ~ - ...
TrOpic of,
Fig. 3. Different zoogeographical regions of world.
Anyone who is familiar with biogeography of South American and
African regions, immediately be convinced by the fact, that similar
habitats are populated with similar animals. These two are extensive
tropical regions and crossed by the equator. They both have similar
habitats in that-have lowland jungles; extensive river systems and
mountain regions. Both regions extends southward to temperate zones.
Yet surprisingly they have dissimilarities in fauna more greatly than
similarities. The characteristic fauna of Africa includes Lions, Elephants,
Rhinoceroses, Hippopotami, many kinds of Antelopes, Giraffes, Zebras,
Hyenas, Lemurs, Baboons, Monkeys with narrow noses and non-
prehenslie tailed Chimpanzees and Gorillas.
In South America, occur Monkeys with broad noses, Tapirs, Odd-
toed hoofed mammals, rodents like Capybara. Agouti, Chinchilla and Paca,
Mountain lions like panthers-Ocelots Jaguars of cat family, well known
Uamas Gaunacos, Vicunas, and Alpacas, Armadillos, many opossums,
Giant Anteaters, Raccoons, spectacled Bears and Sloths and many others.
Thus, if both Africa and S. America have similar varying habitats,
then how it could have happened, to them to possess different fauna
instead similar fauna? We cannot simply satisfy with such an answer
that suitability of habitat is important. Because, we do find similarities in
fauna of both regions. They both have such widely ranging animals, bats,
rats, squirrels, hares and rabbits, etc. The other alternative answer might
be the accessibility of these two regions to the animals found in them.
Let us examine this point here more briefly.
Simpson has established a relationship "faunal stratification"
between the separateness of animals and their period of length of
appearance in S. America. Based on it, he concludes that armadillos and
sloths are the oldest inhabitants of S. America since early coenozoic
times. They have not appeared in other part of the world. Monkeys and
field mice have formed part of S. American fauna during mid and late
coenozoic times. While the rest of the fauna have independently evolved.
These facts have been ascertained by fossil record.
The record reveals that during long periods S. American forms have
no contact with those on other continents. Occasionally animals might
have reached the continent by island hopping across the intervening
sea. This type of dispersal is best seen in fauna on continental islands.
For the most part the isthums of Panama, that links S. America to N.
America was submerged and thereby the two continents are isolated.
264 Encyclopaedia of Petroleum Science and Engineering
When once geographical isolation take place local fauna along with
invaders might evolve into distinct species, on many different times and
have become unique to S. America.
Thus, this, is the only possibility for the same habitats in different
parts of earth have been populated by different animals and plants. This
fact suggests that animals today we see in different biogeographical
regions, have descended from their predecssors with different structures,
and have migrated from their place of origin to their new areas, but have
failed to return to their place of origin, because it is separated
Continental Islands
These islands are located on continental shelves of continents.
These islands sometimes are connected to mainland when ocean water
recedes or the level of islands land rises.
The fauna and flora of continental islands characteristically
resembled those of continents, to which they are formerly joined. One
interesting feature is the presence of amphibianbs and mammals on
continental islands. Islands hopping in these animals is less likely and
hence they might have arrived these island through land connections.
Thus, these evidences have established that biological evolution is
a fact but not a dogma. Consequently, the biologists conviction that,
through a series of changes resulting from natural selective processes,
life came to the state known today, is of such magnitude that entire
science of biology has been oriented according to the evolutionary
doctrine. Organisms have been reclassified according to proposed
evolutionary relationships. Geneticists interpret their results as possible
mechanisms of evolution or sources of variation. So powerful the idea is
,this today, that only a text organization based on evolutionary doctrine
would truely represent the science of biology.
Appendix 265
List of Oil & Gas Fields with Years of Discovery
Name ofField Year
1. Cambay 1958
2. Ankleshwar 196>
3. Rudrasagar 196>
4. Kalol 1961
5. Sanand 1962
6. Waval 1962
7. Kosamba 1963
8. Nawagam 1963
9. Olpad 1963
10. Lakwa-Lakhmani 1964
11. Kathana 1965
12. Bakrol 1966
13. Dholka 1966
14. Ahmedabad 1967
15. Allora 1967
16. Manhera Tibba
17. NorthKadi 1967
18. Geleki 1968
19. Sobhasan 1968
20. SouthKadi 1968
21. Hazira 1969
22. Wasna 1969
266 Encyclopaedia of Petroleum Science and Engineering
Name of Field Year
23. Balol 1970
24. Borholla 1970
25. Dabka 1970
26. Amguri 1971
27. Baola 1971
28. Indrora 1971
29. Kanwara 1971
30. Santhal 1971
31. Asjol 1972
32. Lanwa 1972
33. Linch 1972
34. North Balol 1972
35. Changpag 1973
36. Bombay High 1974
37. Charali 1974
38. Sisvva 1974
39. Southwest Motwan 1974
40. Bararnura 1975
41. Nandasan 1975
42. North Kathana 1975
43. Bassein 1976
44. Bhandut 1976
45. BHE 1976
46. D--l 1976
47. Demulgaon 1976
48. Thalora 1976
49. Panna 1976
SO. South Sobhasan 1976
51. West Sobhasan 1976
52. B-37 1977
Appendix 267
Name ofField Year
53. Heera 1m
54. Jotana 1m
55. Karaikal 1m
56. Padra 1m
57. B-51 1978
58. B-55 1978
59. Dahanu(B - 12) 1978
roo Gajera 1978
61. Matar 1978
62. Sisodra 1978
63. South Tapti 1978
64 Vnaj 1978
65. West Motawan 1978
66. Akhaj 1979
67. R-9 1979
68. Ratna(R-12) 1979
69. An-I 1980
70. Dahej 1980
71. G-l 1980
72. MahiHigh 1980
73. Mid Tapti 1980
74. PY-l 1980
75. R-l 1980
76. Badarpur 1981
77. Charaideo 1981
78. Kudara 1981
79. Langhanaj 1981
80. Lohar 1981
81. Mewad 1981
82. Mukta (B - 57) 1981
268 Encyclopaedia of Petroleum Science and Engineering
Name of Field Year
83. Nahorhabi 1981
84. Namti 1981
85. Napamua 1981
86. Ph-9 1981
87. Barsilla 1982
88. D-12 1982
89. Gamij 1982
90. Gojalia 1982
91. Modhera 1982
92. Ognaj 1982
93. G-2 1983
94. Ghotaru 1983
95. Manikyanagar (Rokhia) 1983
96. R-13 1983
97. R-8 1983
98. Raj ole 1983
99. Wadu-paliyad 1983
100. B-178 1984
101. B-48 1984
102. Bhimanapalli 1984
103. Changmaigaon 1984
104. South Dholasan 1984
105. Gandhar 1984
106. Kaikalur-Vadali 1984
107. KD 1984
108. Kuargaon 1984
109. North Tapti 1984
110. South Mewad 1984
111. South Viraj 1985
112 B-I72 1985
Appendix 269
Name ofField Year
113. B-174 1985
114. Buhubar 1985
115. Chumukedima 1985
116. D-18 1985
117. Katjisan 1985
118. Kaza 1985
119. Kovilkalappal 1985
120. Laksbmijan 1985
121. Limbodra 1985
122. Narsapur 1985
123. Narima.nam 1985
124. Pakhajan 1985
125. Panna East 1985
126. CA 1986
127. m 1986
128. Konaban (Rokhia) 1986
129. Palakollu 1986
130. R-71 1986
131. R-7A 1986
132. Sonari 1986
133. Tatipaka - Kadali 1986
134. Adamtila 1987
135. Agartala Dome 1987
136. B-134 1987
137. B-179 1987
138. B-80 1987
139. Bhuvanagiri 1987
140. C-22 1987
141. C-24 1987
142. GS-8 1987
270 Encyclopaedia of Petroleum Science and Engineering
Name of Field Year
143. Neelam (B -131, B -132) 1987
144. Pasarlapudi 1987
145. Rawa(GS-16) 1987
146. South Malpur 1987
147. Thirukalar 1987
148. Bantumilli 1988
149. Bechraji 1988
150. Cbintalapalli 1988
151. Elao 1988
152. Hilara 1988
153. Mandapeta 1988
154. Mansa 1988
155. Nada 1988
156. Nannilam 1988
157. PY-3 1988
158. R-lO 1988
159. Sabannati (Motera) 1988
1 (i). SD-l 1988
161. SD-4 1988
162. Unawa 1988
163. Uriamghat 1988
164. Adiyakkamangalam 1989
165. Andada 1989
166. B-119/121 1989
167. B -19 (Mukta) 1989
168. B-46 1989
169. Banskandi 1989
170. GK-29 1989
171. Khoraghat 1989
172. Lingala 1989
Appendix 271
Name of Field Year
173. SD-14 1989
174. Southwest Patan 1989
175. Tynephe 1989
176. West Bechraji 1989
177. B-149 1990
178. B-157 1990
179. B-163 1990
180. B-183 1990
181. B-188 1990
182. Bakhri Tibba 1990
183. Bankia 1990
184. Elamanchilli 1990
185. GS-38 1990
186. Karnalapuram 1990
187. Kharatar 1990
188. Manepalli 1990
189. Mori 1990
190. Nandej 1990
191. Palej 1990
192. Sangapur 1990
193. South Heera (R - 15A) 1990
194. Tiruvarur 1990
195. B-126 1991
196. B-147 1991
197. B-192 1991
198. B-192A 1991
199. Bandamurlanka - N 1991
200. BS-12 1991
201. BS-13 1991
272 Encyclopaedia of Petroleum Science and Engineering
Name of Field Year
202. C-26. 1991
203. Endamuru 1991
204. Jambusar 1991
205. Kim 1991
206. Penumadam 1991
2fJl. Attikadai 1992
208. B-127 1992
200. B-173A 1992
210. B-180 1992
211. B-45 1992
212. B-59 1992
213. C-23 1992
214. G K - 2 2 ~ C 1992
215. GS-29 1992
216. Gulf-A 1992
217. Gulf-D 1992
218. Kavitam 1992
219. Kesanapalli 1992
220. Khambel 1992
221. Medapadu 1992
222. Munnnidivaram 1992
223. Nandigama 1992
224. Vadatheru 1992
225. Vijayapuram 1992
226. WO-5 1992
227. Achanta 1993
228. GS-15 1993
229. Kuttanalur 1993
230. Mattur 1993
231. Pallivaramangalam 1993
Appendix 273
Name of Field Year
232. Ponnamada 1993
233. B-15 1994
234. B-193 1994
235. C-37 1994
236. GS-23 1994
237. Halisa 1994
238. Patharia 1994
239. Perugulam 1994
240. Adivipalem 1995
241. B-153 1995
242. B-15A 1995
243. Bhubandar 1995
244. C-43 1995
245. Kamboi 1995
246. Lankapalem 1995
247. 1995
248. 1995
249. Pundi 1995
250. WO-15 1995
251. WO-16 1995
252. Asmali 1996
253. B-28 1996
254. C-39 1996
255. Enugupalli 1996
256. Hirapur 1996
257. Kesanapalli-west 1996
258. Kherwa 1996
259. Kizhvalur 1996
260. Kuthalam 1996
261. 1996
274 Encyclopaedia of Petroleum Science and Engineering
Name of Field Year
262. Rangapuram 1996
263. Wadasma 1996
264. B-23A 1997
265. Magatapalli 1997
266. Neyveli 1997
267. Periyapattinam 1997
268. Ramanavalsai 1997
269. Sadewala 1997
270. Tulsapatnam 1997
271. Anklav 1998
272. Gokarnapuram 1998
273. Kali 1998
274. Kesavadaspelam 1998
275. Vatrak 1998
Periodwise Discoveries
1956-58 1
1959-63 8
1963-70 16
1970-74 14
1974-80 36
1981-89 101
1989-93 56
1993-98 43
Source: 1. Farooqi I.A., 2000; The story of ONGC; Microsoft Technopoint
(I) Pvt. Ltd., Conn aught Place, Dehradun.
Appendix 275
Production Profile
YEAR OIL GAS LPG C2C3 Saleo! Balance
Gas Rec.
(MMT) (MMM3) (MMT) (MMT) Oil (MMT)
1961-62 0.044 6.9
1962-63 0.4622 72.9
1963-64 0.7238 116.6
1964-65 0.7696 135.6
1965-66 1.4505 332.3
1966-67 2.5634 449.7 90.35
1967-68 2.8281 495.3 107.85
1968-69 3.1037 565.2
1969-70 3.6506 504.4 93.44
1970-71 3.647 495.9 87.63
1971-72 4.0167 571.4 85.35
1972-73 4.0905 587.2 72.55
1973-74 4.0465 576.8 82.35
1974-75 4.5365 743.1 85.71
1975-76 5.2742 944.1 102.09
1976-77 5.7661 1035.7 235.57
1977-78 7.6042 1331.5 266.33
1978-79 8.9176 1516.3 312.53
1979-80 9.5191 1660.9 314.91
1980-81 9.2191 1614.6 972.15 328.42
1981-82 13.1825 2435.1 0.0734 1230.41 429.74
1982-83 18.2483 3468.3 0.1608 1856.72 429.39
1983-84 23.1671 4366.2 0.1957 2222.51 482.81
1984-85 26.2764 5604 0.2418 465.19
:- ~ . 90..01..
1985-86 27.5362
6588.5 0.3208 ..
2789.94 450.96
1986-87 27.8564 8146.9 0.4512 3308.3
1987-88 27.9095 9874.9 0.5099 5874 525.24
1988-89 29.6442 11718.4 0.6742 6977.72 583.18
276 Encyclopaedia of Petroleum Science and Engineering
YEAR OIL GAS LPG C2C3 Saleo! Balance
Gas Rec.
1989-90 31.9511 1545.6 0.7181 8610 646.84
1990-91 30.3295 16318.6 0.8758 0.0275 9866 671.39
1991-92 27.8244 17056.2 0.9736 0.1374 11269 704.1
1992-93 24.4273 16317.9 0.9229 0.2555 13035 696.72
1993-94 24.2151 16573.3 0.9308 0.3074 13371 676.99
1994-95 29.356 17935.5 0.985 0.4243 13961 663.49
1995-96 31.79 20951.3 1.1123 0.4886 17047
1996-97 28.685 21266 1.1286 0.5105 17219 665.18
1997-98 29.22 23140 1.144 0.557 19220 622.76
1998-99 27.55 23970 1.181 0.507 19390
Financial Profile
Operating Operating Net Profit
Year Income Expen. Profit Interest Tax Net Per
Income Employee
1971-72 49 35 14 2 0 12 0.06
1972-73 51 41 10 3 0 7 0.03
1973-74 82 55 27 2 0 25 0.11
1974-75 144 93 51 2 0 49 0.22
1975-76 169 129 40 2 14 24 0.1
1976-77 203 158 45 8 0 37 0.15
1977-78 298 224 74 15 7 52 0.21
1978-79 383 280 103 21 9 73 0.28
1979-80 436 306 130 23 52 55 0.21
1980-81 452
3 5 ~
94 48 0 46 0.16
1981-82 1348 689 659 86 198 375 1.22
1982-83 2385 1115 1270 87 490 693 2.1
1983-84 3473 1777 1696 88 802 806 2.18
Operating Operating Net Profit
Year Income E'pen.
Profit interest Tax Net Per
Income Employee
1984-85 4035 2274 1761 134 745 882 2.12
1985-86 4388 2332 2056 158 596 1302 2.96
1986-87 5627 3401 2226 121 621 1484 3.42
1987-88 6107 3990 2117 75 535 1507 3.42
1988-89 6972 4801 2171 77 493 1601 3.52
1989-90 8133 6012 2121 100 397 1624 3.46
1990-91 9605 8631 974 (125) 51 1048 2.17
1991-92 8147 7636 511 (19) 122 408 0.84
1992-93 9707 8891 816 33 5 788 1.66
1993-94 8174 6148 2026 236 195 1595 3.39
1994-95 13628 10760 2868 583 (60) 2345 5.13
1995-96 13530 10694 2836 482 409 1945 4.37
1996-97 13336 10471 2865 332 499 2034 4.7
1997-98 15346 11935 3411 99 634 2678 6.35
1998-99 15103 11545 3558 (16) 820 2754 6.71
Note: Net profit per employee is ill Lakhs of Rupees
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278 Encyclopaedia of Petroleum Science and Engineering

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282 Encyclopaedia of Petroleum Science and Engineering
TOI 35.5.2007
Bare Truth: These two pictures - one taken in 1968 (top) and the other in
2007 - show the retreating Rongbuk Glacier of Mount Everest on the Tibetan
plateau. The rugged Tibet plateau, seen as a sensitive barometer of the impact
of global warming, IS experiencing accelerating glacial melt and other ecological
changes. The mountainous region's glaciers have been melting at an annual average
rate of 131.4 square km over the last 30 years.
-------: .-
Feeling the Heat: A Nasa Image shows a portion ofCunada's Northwest Passage.
Arctic Ice has shrunk to the lowest level on record and has raised the possibIlIty
of the Northwest Passage becoming an open shipping lane.
Appendix 283
TOI 15.12.2007
Future Tense? Activists hold their noses as they pretend to learn to swim due
to increased sea levels caused by global warming. They were protesting in front
of the venue of the climate change conference in Bali, IndonesIa, on Tuesday. As
the meeting began a hunt for a new global deal to fight global warming by 2009,
it witnessed skIrmishes over how far Chma and India should curb greenhouse
gas emIssions.
284 Encyclopaedia of Petroleum Science and Engineering
TOI 31.7.2007
Alternative Energy: The world's biggest 40,000 square metre root-based solar
system IS seen In the Southern German town ofBuerstadt. It rains frequently In
Germany. Yet the country has managed to become the worlds leading solar power
generator and 55% of the world's photovoitaic (PV) power is generated on solar
panels. So far 3% of Germany's electricity comes from the sun, but government
wants to false the share of renewables to 27%. It is a thriving mdustry with
booming exports that has created tens of thousands of jobs. There are now more
than 300,000 PV systems In Germany with growing demand from households,
farmers and small bUSInesses, while the nation's energy law had planned fOf
Appendix 285
Oil Imports to Grow 85%: India's dependency on oil imports is likely increase
to about 85% by 2012 from the current level of70%, driven by the rising demand
for energy, industry body Assocham said on Thursday.
This despite "refining capacity in India poised to increase by 58% to touch
235 million tonnes in the next five years ... in view of the growing demand for
energy with little resources at its disposal for harnessing alternative sources,"
the chamber said. A chamber paper on 'Future Imperatives of Crude Oil Scenario'
shows that India's dependence on crude oil import would rise, as domestic
discoveries have not been taking place, to touch, to touch the level of 12-13%
compared to 7-8% at present.
TOI 9.8.2007
Largest planet discovered: Astronomers have discovered the largest-known
planet - about 70% larger than Jupiter. Located in the constellation of Hercules,
it circles a star about 1,435 light years away from Earth.
286 Encyclopaedia of Petroleum Science and Engineering
TOI 18.12.2007
A sharper imbalance
The- 'NOr"'}. oceans, wtIidI about 1I third of 1110 (.arbon dklKlcte emitted from buf'ntng
__ ., ..... ....roc.
........ ..,..1'IudIen
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TOl 19.12.2007
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288 Encyclopaedia of Petroleum Science and Engineering
TOI 2.9.2007
Ny Alesund (Norway): India will soon have a permanent postal
address in the Arctic. Taking advantage of the unique international
Svalbard Treaty signed in 1920, to which it was a signatory, India will be
able to set up a permanent research station at Ny Alesund, on the
Svalbard archipelago which comes under Norwegian sovereignty,
boosting its knowledge of climate change, other critical natural
phenomena and the disturbance humans cause to nature's processes.
Perhaps waking a bit too late in the day, considering India has
already sent 26 missions to the Antarctic and has two permanent bases
there, the research base at 79 degree north will be set up under a five-
year contract with the Norwegian government and Kings Bay, the
Norwegian government-held company that runs the logistics at the
research station.
New Address: (From Left) Researchers S.M. Singh, e.G Deshpande
and Dhruv Sen Singh, who were part of the mission to the Arctic.
The Svalbard Treaty allows every signatory country, that includes
Afghanistan, to set up any business and activity on the archipelago -
Appendix 289
which earlier was better known for its coal mining industry -as long as
it falls within Norwegian regulations. Formal negotiations between the
two countries are close to completion for India to take position close to
the North Pole.
The move to set up the permanent station at Ny Alesund matured
with India sending its fIrst Arctic mission recently. Three of the fIve
researchers sent as part of the fIrst of the two teams comprising the
mission have already made themselves at home at the international
research station. Rubbing shoulders with the Chinese, Germans and
French, and obviously the Norwegian researchers, they are busy
collecting samples.
The sun never sets, quite literally in the Arctic summer. Besides the
bags of tagged samples one finds kept in an old school building of the
camp, there are other tell tale signs that Indian researchers are at work-
empty packets of Indian cigarettes, though stashed well in the bins, not
strewn around.
"This is not unfamiliar climes as we have a long history in the
Antarctic but this surely provides completely new avenues for research
to us," explains an excited Dr C G Deshpande, scientist at the Indian
Institute of Tropical Meteorology and member of the team.
In his politeness, he never lets out the political significance of his
research at the Arctic. His measurements of aerosols (particles of
pollution generated naturally as well as from human activity) will help
India pin down the impact of pollution from the developed countries on
the Arctic, in contrast to studies that have blamed Indian for adding to
the aerosol pollution earlier.
Dr S M Singh, scientist at the National Centre for Antarctic and Ocean
Research, the second of the triumvirate at Ny Alesund, is picking up soil
and water samples around the station. An ankle sprained, he still walks
around for his pound of soil. "There is little time, we have only two more
weeks here. I am collecting microbes from the region, to compare with
those collected at the Antarctic. These microbes can help measure
changes in seasons as well as provide potential solution to diseases like
leukoderma. "
Dhruv Sen Singh, reader in the Department of Geology of Lucknow
University, listens to Lata songs in the evenings, while munching on
sweets and namkeen in his warm room at the station, and completes the
triumvirate. His job: study glaciers and their habits.
290 Encyclopaedia of Petroleum Science and Engineering
TOI 12.8.2007
Ottawa: In the latest of a series of claims over portions of the Arctic,
Canada said on Friday that it planned to build two new military bases in
the for north to assert its sovereignty over the Northwest Passage.
The status of the shipping route, navigable only with the aid of ice-
breakers for a small part of the year, has been the source of a longstanding
dispute that has pitted Canada against the United States and Russia.
Warming climate trends may reduce ice in the passage and make it a
substantially shorter alternative to the Panama Canal for commercial
shipping. The seabed under the route may also contain oil, gas and
minerals that could be extracted if the ice cover diminishes.
Prime minister Stephen Harper, who has been touring the Canadian
Arctic for several days, said the military would convert a former mining
site in Nanisivik, in the territory of Nunavut, into a deep-water port and
ship refueling station. Existing government buildings in Resolute Bay,
Nunavut, will be turned into an Arctic training center for the army, and
the Canadian Rangers, mostly made up of Inuit volunteers, will be
increased by 900 members and re-equipped.
Harper's tour and announcements took place after a Russian mission
planted a tiny flag in a titanium capsule on the seabed at the North Pole
last week. While the effort was billed as a claim on the territory, it was
seen as mostly symbolic.
TO! 22.8.2007
Ice May Disappear by Middle of Century: Expert
Ny Alesund, Norway: Previously unknown islands are appearings
whether global warming is outpacing UN projections, experts said .
. Polar bears and seals have also suffered this year on the Norwegian
archipelago of Svalbard because the sea ice they rely on for. hunts melted
far earlier than normal.
Norwegian environment minister Helen Bjoernoy said at a seminar of 40
kms of the North Pole. "This acceleration may be faster than predicted"
by the UN climate panel this year, she said. Ny Alesund calls itself the
world's most northerly permanent settlement, and is a base for Arctic
Appendix 291
The UN panel of 2,500 scientists had said in February that summer
greenhouse gases caused by fossil fuel use.
Melting Point: Ice has fallen below the 2005 record low absolute
mmimum, say experts.
Christopher Rapley, director of the British Antarctic Survey, told the
seminar, accusing the UN's Intergovernmental Panel on Climate Change
(IPCC) of underestimating the melt. The thaw of glaciers that stretch out
said Kim Holmen, research director at the Norwegian Polar Institute,
polar bears and other species."
environmental expert with the Norwegian governor's office on Svalbard.
292 Encyclopaedia of Petroleum Science and Engineering
court. Islands have also appeared in recent years off Greenland and
could raise world sea levels.
people live in the fjordside settlement, backed by snow-covered
mountains. Bjoernoy said it was freak storm that did not detract from an
overall warming trend.
TOI 25.7.2007
New Delhi: With the government showing keen interest in increasing
the country's scientific understanding of glaciers in the wake of global
warming threats, India will soon send a team of researchers to the Arctic
to study glacial geology and pursue research in other key fields.
While India has sent 26 missions to the Antarctic and made its
presence felt in the polar research fraternity, this will be its first foray
towards the North Pole.
New Venture: This will be India's first foray towards North Pole.
Norway has agreed to host Indian scientists on its base at Svalbard,
an archIpelago halfway between the North Pole and Norway. The Svalbard
research camp of the Norwegian Polar Institute will be used by the Indian
scientists for their research.
Appendix 293
India moved fast to utilise the opportunity when the Norwegian
government offered visiting earth sciences minister Kapil Sibal facilities
at its base in the archipelago for research. The ministry then asked key
scientific institutions to put in proposals for possible studies. Fourteen
proposals were received by the ministry, but after review, only eight were
The approved proposals include research into geology. Arctic
microbes and aerosols. While the second area of research, microbes, will
have implications for biotechnology, the other two will add to Indian
scientists' understanding of how the dynamics of climate change work.
"We have already done work on the Antarctic microbes, so this will
be a good follow-up for us," P S Goel, secretary, ministry of earth
sciences, told TOL "Because this is our first foray into the area, our
scientists will get an opportunity to gain basic knowedge on the regionand
build on the knowledge gained in the Antarctic," he added.
The Arctic research programme will be conducted in two phases with
five experiments being carried out by the first contingent of scientists to
go this year, and the rest three to be carried out by a second contingent
in the second half of 2008.
The Norwegian government has offered its base as well as the use
of its equipment but the Indian contingent will have to take along some
equipment with it to carry out the research.
TOI 10.8.2008
Clean geothermal energy could fuel the world in the future
The ancient Romans drew on hot springs for bathing and heating
homes without having to pay a single coin. That's because a clean, quiet
and virtually inexhaustible source of renewable energy lies literally
beneath our feet. The interior of the earth is hot-up to 6,500 degrees
Celsius at the core and generally cooling off towards the top but still
about 200 degress Celsius three to 10 kilometres below the surface. In
Switzerland, Australia and elsewhere engineers are drilling down to these
depths to tap the heat trapped in hot rocks by injecting cold water into
the shafts and bringing it up again superheated to generate power though
a steam turbine. They feel it could meet the electricity needs of nearly
10,000 households and heat over 2,700 homes.
In India the potential for harnessing geothermal power has been
under investigation since the late 1960s. Currently, an organisation
294 Encyclopaedia of Petroleum Science and Engineering
incubated in lIT-Bombay is carrying out a year-long survey to assess
the heat trapped beneath the Konkan coastline. Preliminary calculations
indicate this could generate some line. Preliminary calculations indicate
this could generate some 2,000 MW of power, reason enough for the
ministry of non-conventional energy of Maharashtra, a state with a
shortfall of approximately 5,000 MW, to be interested in co-funding the
project. The total stored heat potential in India, however, is believed to
be the equivalent of27.6 billion barrels of petroleum.
At present, geothermal power supplies lees than 0.5 per cent of the
world's energy. But global estimates of exploitable geothermal energy
vary between 65 and 138 Gw. Taking this into account a 2006 MIT report
concluded that extractable resources would be sufficient to provide all
the world's energy needs for several millennia. What's needed is to move
beyond easily developed hydrothermal systems, such as hot springs and
geyers, and begin to tap the earth's deeper, stored heat, which is available
everywhere. The report estimates that a billion dollars of investment in
research and development over the next 15 years would lead to the
enhanced geothermal systems (EGS) that would make this possible.
Since the earth's heat is everywhere, EGS would deliver the ultimate
form of energy security: no more dependence on suppliers of fossil fuels,
or even uranium. And it's one of the cleanest forms of energy available:
greenhouse gas emissions are close to zero. India ought to map its
existing hydrothermal resources in Maharashtra and elsewhere, as well
as collaborate in exciting research projects being undertaken in EGS in
various countries.
TOI 14.92007
Planet will Outlast Apocalypse After 5B Yrs; Venus will be Swallowed:
There is new hope that Earth, if not the life on it, might survive an
apocalypse five billion years from now.
That is when, scientists say, the Sun will run out of hydrogen fuel
and swell temporarily more than 100 times in diameter into a so-called
red giant, swallowing Mercury and Venus.
Astronomers are announcing that they have discovered a planet that
seems to have survived the puffing up of its home star, suggesting
there is some hope the Earth could survive the aging and swelling of the
Appendix 295
The planet is a gas giant at least three times as massive as Jupiter. It
orbits about 150 million miles from a faint star in Pegasus known as V
391 Pegasi. But before that star blew up as a red giant and lost half its
mass, the planet must have been about as far from its star as Earth is
from the Sun-about 90 million miles-according to calculations by an
international team of astronomers led by Roberto Silvotti of the
Observatorio Astronomico di Capodionte in Naples, Italy.
Ray of Hope
Silvotti said the results showed that a planet at Earth's distance "can
survive" a red giant, and he said he hoped the discovery would prompt
more searches. "With some statistics and new detailed models, we will
be able to say something more even to the destiny of our Earth (which,
as we all know, has much more urgent problems by the way)," he said
via e-maIl. Silvotti and his colleagues reported therr results on Thursday
in Nature.
In an accompanying commentary, Jonathan Fortney of Nasa 's Ames
Research Center in California wrote, "This system allows us to start
examining what will happen to planets around stars such as our own
Sun as they too evolve and grow old."
The star V 391 Pegasi is about 4,500 light years from Earth and is
about half as massive as the Sun, burning helium into carbon. It will
296 Encyclopaedia of Petroleum Science and Engineering
eventually sigh off another shell of gas and settle into eternal senescence
as a white dwarf.
Meanwhile, the star's pulsations cause it to brighten and dim every
six minutes. After studying the star for seven years. Silvotti and his
colleagues were able to discern subtle modulations in the six-minute cycle,
suggesting that the star was being tugged to and fro over a three-year
period by a massive planet. "Essentially, the observers are using the star
as a clock, as if it were a GPS satellite moving around the planet," said
Fred Rasio of Northwestern University.
This is not the first time that a pulsing star has been used as such a
clock. In 1992, astronomers using the same technique detected a pair of
planets (or their corpses) circling the pulsar PSR 1257+ 12. And only on
Wednesday, X-ray astronomers from the Goddard Space Flight Centre in
Greenbelt, Maryland, and the Massachusetts Institute of Technology
announced that they had detected the remains of a star that radiation
had whittled down to planetary mass circling a pulsar in the constellation
Sagittarius. Those systems have probably endured supernova explosions.
The Pegasus planet has had to survive less lethal conditions,
although it must have had a bumpy ride over its estimated 10 billion years
of existence. An expert said, "Stellar evolution can be a wild ride for a
planet that is trying to survive, especially inner planets like Earth."
TOI 8-12-2007
Negotiations in Bali for cleaner technology and development
"It cows are causing global warming, and I ate a hamburger, could I
claim carbon credits for helping eliminate a cow?" asks a reader in the
letters coplumn of a US newspaper. Despite George Bush's refusal to
commit the US to any international agreement that would adopt emissions
targets, it is clear that climate change has com to impact people's
consciousness everywhere. At the UN Framework Convention on Climate
Cange meet in Bali, representatives from 190 countries have converged
to compare notes and thrash out agreements on how to tackele the climate
change challenge facing the planet. The US continues to stress the same
points it raised at the last meeting in Montreal in 2005, that it would not
consider any commitment unless India and Cina made similar promises,
since together the three countries are the word's largest polluters.
However, since carbon stocks in the atmosphere - that have triggered
glonal warming - are the result of 300 years of devlopment in
industrialised countries, the rich need to bear higher costs and take more
Appendix 297
responsibility. In a bid to be fair, the UN recommends "common but
differentiated responsibility."
India and China have attracted several projects from developed
countries under the Kyoto Protocol's 'clean development mechanism'.
Under this scheme, the investor earns carbon credits for setting up clean
development projects, often with new technology. H9wever, what did
not take off was saving 2 per cent of earned credits'in an 'adaptation
fund' that would be ploughed back for tackling climate change risks. At
Bali, discussions are on to activate this fund and to step up clean
technology transfer to India, China and African countries.
By taking the lead, the US could set an example in the developed
world. Britain is talking ofa 75 per cent greenhouse gas emissions cutback
by 2050 and has formulated a climate Bill detailing how it would go about
achieving this. The Democrat-majority US Senate has now introduced a
climate Bill; a first-time legislative initiative in the country that would
ask selected industries to reduce emissions to 1990 levels by 2020 and
by a further 65 per cent by 2050.
The Bali conference provides a forum to discuss climate change issues
so that some solutions get incorporated in the negotiating process to create
a new agreement that would come into effect in 2012, when the Kyoto
Protocol ends. India and China as developing world leaders ought to garner
as much financial and technological assistance as they can from developed
countries to reduce climate change risks to leapfrog their way to smart
growth. That means going green without sacrificing growth and prosperity.
TOI 6.12.2007
New Delhi: The carbon cowboys of the world, including Indian
carbon 'bonds', have all rushed to Bali for the global meet on climate
change. The next 10 days of the UN meet could either deflate the existing
$5 billion carbon credit market or expand it dramatically depending on
the fate of the proposals before of the 190 i--
countries gathered there. I
The carbon market is an offshoot of the '
Kyoto Protocol that demands greenhouse
gas emission cuts from rich countries. The
Clean Development Mechanism (CDM)
under the protocol allows rich countries to
buy carbon credits to offset their
targets, in return providing funds to
developing country entities to buy clean
technologies. For Clean Technology
298 Encyclopaedia of Petroleum Science and Engineering
On the table before the gathered 10,000 plus delegates will be several
critical parts of the CDM mechanism. Knowing these could be as critical
for developing countries like India as for rich countries like EU. No
wonder, Bali is seeing one of the largest gathering of businessmen from
around the world. Indian industry associations too have flown
delegations, besides the carbon market dealers also landing up at the
busy tropical station.
One of the key issues to be thrashed out would be the inclusion of
forestry as one of the many CDM project options. India Inc, especially
the paper and pulp industry, is keen to make money from its forestry
operations and the government wants to earn credits from 'avoiding
deforestation' - a climate speak which means demanding money from
rich countries for maintaining the forest cover at the cost of economic
development. It is a contentious issue, because it could provide a lot of
carbon credits if allowed under the CDM process which could also lead
to a crash of prices with supply side seeing a surge.
But the proposal will see opposition from some G-77 countries itself
with Brazil and some other key nations that are losing their forests fast
prefering to keep the forest sector out of CDM and demanding a new
mechanism to deal with it.
For Clean Technology
"The only time that one may see industrialized country industry and
developing world businesses speaking the same language will be when
it comes to relaxing the regulations and conditions for carbon credits," a
senior Indian official from Bali told the Times of India.
At present, there are stringent conditions to be met before a project
is allowed carbon certificatl!s. One key issue is of 'additionality' - proving
that the clean technology project would have been unviable without the
Appendix 299
additional money selling credits generates. The developing world
business wants such conditions to be less tight on their projects to earn
their credits easy.
They also want some environmental conditions to be eased, to
include mega-hydropower projects and nuclear power to be accepted as
carbon credit worthy. Though hydropower is accepted under UN but
EU, the biggest consumer, does not accept carbon credits generated from
such markets. The next 10 days would see parleys on this on the sidelines
of the main meetings.
"One key issue will be the future of the refrigerant gases in the CDM
mechanism," another Indian official said. Some of the biggest credit
generating projects have come from destruction of harmful refrigerant
gases. But the mechanism at present allows for not only older existing
facilities to be corrected using credit mechanism but also those
businesses that will produce these harmful gasses in future to claim
credits for fIxing their plants.
TOI 15.11.2007
Study Based on Excavations made from Quarries in India
New Delhi: It may have been a volcanic eruption and not so much
of a meteor strike that could have wIped out the T-Rexes, Stegosaurs
and Raptors from the face of the earth.
Scientists are digging up proof to confirm that giant volcanic
eruptions may have caused the mass dinosaur extinction between 63
million to 67 million years ago.
Experts have long been debating on what caused the wipeout. Some
believe it was an asteroid or comet impact which left a vast crater at
Chicxulub on the coast of Mexico that resulted in the K-Tor Cretaceous-
Tertiary extinction event, which killed off all dinosaurs. Others contend
that a series of colossal volcanic eruptions created the gigantic Deccan
much as 1.5 million sq Ian, or more than twice the area of Texas.
According to the latest fmdings, presented recently at the annual
meeting of the Geological Society of America in Denver, Princeton
University paleontologist Gerta Keller suggested the mass extinction
which spewed 80% of the lava found at the Deccan Traps.
Traps to mass extinction," Dr Keller said.
300 Encyclopaedia of Petroleum Science and Engineering
Keller and colleagues focused on marine fossils excavated from
quarries at Rajalunundry, India, near the Bay of Bengal, about 1,000 km
southeast of the centre of the Deccan Traps near Mumbai. Specifically,
they looked at the remains of microscopic shell-forming organisms known
as foraminifera.
Keller said, "Previous work had only narrowed the timing of the
Deccan eruptions of the Deccan eruptions to within 300,000 to 500,000
years of the extinction event. We believe that before the mass extinction,
most of the formainifera species were comparatively large, very tlahoyant,
very speclialized, very ornate, with many chambers. These foraminifera
were roughly 200 to 350 microns large or a fifth to a third of a millimetre
She added, "When the environment changed, as it did around K-T,
that prompted their extinction. The foraminifera that followed were
absolutely no omarnentation, just a few chambers." The researchers found
that these simple foraminifera seemed to have popped up right after the
man; phase of the Deccan volcanism. This, in turn, hints these eruptions
Keller stressed that these findings did not deny that an impact
several impacts may have had a hand in the mass extinction.
The dinosaurs might have faced an unfortunate coincidence of a
one-two punch of Deccan volcanism and then a hit from space, she
significant impact," she added.
TOI 16.8.2007
Moscow: Russian strategic bombers on Tuesday began five days of
exercises over the North Pole, marking the latest in a series of displays
of Moscow's military muscle.
The nuclear-capable bombers will practice firing cruise missiles,
navigation in the polar region and aerial refuelling manoeuvres, the
Russian air force said.
The exercises come barely a week after Russian strategic Tu-95
bombers tlew over the Pacific to within a few hundred kilometres of the
US military base on Guam-and, according to a Russian general,
exchanged grins with US fighter pilots sent to intercept.
Appendix 301
They also follow recent attempts by Moscow to bolster Russia's
territorial claims in the Arctic region.
One Russian air force officer said he expected US interceptors would
once again make their presence felt during this week's exercises.
"It is a traditional practice for military pilots to see foreign pilots
come up to meet them and say hello," he said. "The US are aware of our
exercise," he said.
Russia's long-range bombers have been involved in a number of
other exercises recently. On July 20, Norway and UK scrambled its fighter
planes after Norway detected Russian bombers flying over the North
sea between Norway and UK.
TOI 1.9.2007
New Delhi: Faced with the danger of receding Himalayan glaciers
and its catastrophic effect on the ecology of the region, India has taken
up the issue with China for a joint selution to the problem.
"I had raised the issue with the Chinese president and it was agreed
that there should be more discussions to work out a joint solution," Prime
Minister Manmohan Singh said while intervening in the reply to a
question in Rajya Sabha on Thursday.
He said the melting of glaciers was an important issue because it
could have a catastrophic effect on the ecology of not only the region
but also the world.
In response to a question about the exact nature of the danger faced
by India due to shrinking of glaciers, minister of state for environment
and forests Namo Narain Meena said, "The melting of glaciers will
ultimately trigger more droughts, expand desertification and increase sand
storms. Melting also threatens disruption of water supply as many rivers
emanate from the Himalayas."
The move to hold talks with China comes as a change from India's
earlier stance. India had declined to work with China, Nepal and Pakistan
on Himalayan glaciology earlier owing to security concerns. But recent
reports of the UN panel on climate change has made the government
think twice on issues of data and knowledge sharing on glaciers.
In the last meeting of the Pr-,'I's scientific group on climate change,
the point about generation of data across the subcontinent and sharing
of this data had been highlighted.
302 Encyclopaedia of Petroleum Science and Engineering
While some preliminary work has been done on glaciers on the Indian
side of the Himalayas, scientists recognise that the Indian glacial river
systems-Ganga as well as Brahmaputra-are dependent on the glacial
fonnations in Nepal and China as well.
TOI 3.8.2007
Moscow: Members of Russia's parliament in a mini-submarine planted
their country's flag 4 km below the North Pole at the climax of a mission
to back up Russian claims to the region's mineral r i c h e s ~ ~ ~
"The Mir -1 submarine successfully reached the bottom o{the Arctic
Ocean ... at a depth of 4,261 metres," veteran Arctic explorer and expedition
leader Artur Chilingarov told the Vesti television channel.
A metre-high flag, made of titanium so as not to rust, was deposited on
the seabed, the ITAR-TASS news agency cited an expedition official as
saying. Chilingarov was joined by fellow parliamentarian Vladimir Gruzdev
and four others, three of whom followed in a second mini-submarine, which
touched the seabed 4,302 metres below the surface, Vesti reported.
Miniature submarines from this Russian research vessel dived into the
Arctic Ocean to plant a flag on the seabed under the North Pole
Billed as the first to reach the ocean floor under the North Pole, the
expedition aims to establish that a section of seabed passing through
the pole, known as the Lomonosov Ridge, is in fact an extension of
Russia's landmass.
"We must determine the border. The most northerly border of the
Russian shelf," Chilingarov said in comments broadcast before the dive
from the Akademik Fyodorov research ship leading the expedition.
The voyage reflects growing international interest in the Arctic partly
due to climate change, which is causing greater melting of the ice and
making the area more accessible for research and economic activity.
Appendix 303
The US Geological Survey, a US government agency, said in a report
earlier that some 25% of world oil reserves are believed to be located
above the Arctic Circle. In 2001 Russia made a submission to a United
Nations commission claiming sub-sea rights stretching to the pole. The
current mission is looking for evidence to back up this claim.
TOI 24.8.2007
Race for the seabed could be an environmental disaster
Jeremy Rifkin
If there were any lingering doubts as to how ill-prepared we are to
face up to the reality of climate change, they were laid to rest this month
when two Russian mini submarines dove two miles under the Arctic ice
to the floor of the ocean, and planted a Russian flag made of titanium on
the seabed. This fIrst manned mission to the ocean floor of the Arctic,
which was carefully choreographed for a global television audience, was
the ultimate geopolitical reality TV.
Russian President Vladimir V Putin congratulated the aquanauts while
the Russian government simultaneously announced its claim to nearly
half of the floor of the Arctic Ocean. The Putin government claims that
the seabed under the pole, known as the Lomonosov Ridge, is an
extension of Russia's continental shelf, and therefore Russian territory.
Not to be outdone, Canadian Prime Minister Stephen Harper hurriedly
arranged a three-day visit to the Arctic to stake his country's claim to
the region.
Although in some respects the entire event appeared almost
comical-a kind of late 19th century caricature of a colonial expedition
- the intent was deadly serious. Geologists believe that 25 per cent of
the earth's undiscovered oil and gas may be embedded within the rock
underneath the Arctic Ocean. The oil giants are already scurrying to the
front of the line, seeking contracts to exploit the vast potential of oil
wealth under the Arctic ice. The oil company BP has recently established
a partnership with Rosneft, the Russian state-owned oil company, to
explore the region. Aside from Russia and Canada, three other countries-
Norway, Denmark (Greenland is a Danish possession that reaches into
the Arctic) and the United States-are all claiming the Arctic seabed as
an extension of their continental shelves and, therefore, sovereign
Under the Law ofthe Sea Treaty, adopted in 1982, signatory nations
can claim exclusive economic zones for commercial exploitation, up to
304 Encyclopaedia of Petroleum Science and Engineering
200 miles out from their territorial waters. The US has never signed the .
treaty, amidst concerns that other provisions of the treaty would
undermine US sovereignty and political independence. Now, however,
the sudden new interest in Arctic oil and gas has put a fIre under US
legislators to ratify the treaty, lest it is edged out of the Arctic oil rush.
What makes the whole development so utterly depressing is that
the new interest in prospecting the Arctic subsoil and seabed for oil and
gas is only now becoming possible because of climate change. For
thousands of years, the fossil fuel deposits lay locked up under the ice
and inaccessible. Now, global warming is melting away the Arctic ice,
making possible, for the fIrst time, the commercial exploitation of the oil
and gas deposits. Ironically, the very process of burning fossil fuels
releases massive amounts of carbon dioxide and forces an increase in
the earth's temperature, which in turn, melts the Arctic ice, making
available even more oil and gas for energy. The burning of these potential
new oil and gas frods will further increase CO
emissions in the coming
decades, depleting the Arctic ice even more quickly.
But the story doesn't stop here. There is a far more dangerous
aspect to the unfolding drama in the Arctic. While governments and oil
giants are hoping the Arctic ice will melt quickly to allow them access to
the world's last treasure trove of oil and gas, climatologists are deeply
worried about something else buried under the ice, that if unearthed,
could wreak havoc on the earth's biosphere, with dire consequences for
human life.
Much of the Siberian sub-Arctic region, an area the size of France
and Germany combined, is a vast frozen peat bog. Before the previous
Appendix 305
ice age, the area was mostly grassland, teeming with wildlife. The coming
of the glaciers entombed the organic matter below the permafrost, where
it has remained ever since. While the surface of Siberia is largely barren,
there is as much organic matter buried underneath the permafrost as there
is in all of the world's tropical rainforests.
Now, with the earth's temperature steadily rising because of CO
and other global warming gas emissions, the permafrost is melting, both
on land and along the seabeds. If the thawing of the permafrost is in the
the production of CO
If the permafrost thaws along lake shelves, in the
absence of oxygen the decomposing matter release methane into the
atmosphere. Methane is the most potent of the greenhouse gases, with
a greenhouse effect that is 23 times greater than that of CO
Researchers are beginning to warn of a tipping point sometime within
this century when the release of carbon dioxide and methane cou' create
an uncontrollable feedback effect, dramatically warming the atmosphere,
which will, in turn, warm the land, lakes and seabed, further melting the
permafrost and releasing more carbon dioxide and methane into the atmc
phere. Once that threshold is reached, there is nothing human beings
can do, of a technological or political nature, to stop the runaway
feedback effect. Scientists suspect that similar events have occurred in
the ancient past, between glacial and interglacial periods.
Katy Walter of the Institute of Arctic Biology at the University of
Alaska in Fairbanks and her research team calls the permafrost melt a
giant "ticking time bomb". A global tragedy monumental proportions is
unfolding at top of the world, and the human race is all oblivious to
what's happening.
The writer is president, The Foundation Economic Trends,
Washington, DC.
TOI 13.9.2007
They were either Slaughtered by Homo Sapiens or Intermingled with
them: Study
Paris: The great whodunnit of palaeontology has been given a new
twist with findings that the Neanderthals were in all likelihood not killed
off by a mini-Ice Age, as some authorities contend. Neanderthals, smaller
and squatter than Homo sapiens, lived in parts of Europe, Central Asia
and the Middle East for around 170,000 years.
306 Encyclopaedia of Petroleum Science and Engineering
One theory is that the Neanderthals were wiped out by a s u d d e ~
cold snap. Alone, their numbers depleted, the Neanderthals eked out their
final moments in caves in modem-day Spain and Gibraltar, goes this
hypothesis. One of the problems of exploring the Neanderthal saga is to
get an accurate date for when all this may have happened. The main
dating technique is to test fossils for levels of a background isotope in
the environment, carbon 14.
Researchers led by Polychronis Tzedakis at the University of Leeds
and the University of the Aegean, Greece, sought a different yardstick:
one based on climate rather than chronology. They found one in a
sedimentary core drilled in the seabed of Cariaco Basin, Venezuela, in
which records of past climate events can be related directly to
radiocarbon years.
Visitors at the Museum for Prehistory in Eyzies-de-Tayac, France, look
at an attempted reconstruction of a Neanderthal man and boy.
The team probed three dates that have been variously proposed for the
end of the Neanderthals. The evidence from these days comes from artifacts
found in Gorham's Cave in Gibraltar, where Neanderthals interspersed
periods of residence with modem humans. The two most-commonly
proposed dates are 32,000 years, 28,000 years and 24,000 years ago.
That coincided with Earth's last "glacial era", a term that despite its
name also included periods of instability, warm and cold alike. The most
redoubtable of these periods were so-called Heinrich Events, when the
balmy North Atlantic drift, which supplies Western Europe with warmth
despite its high northerly latitude, abmptly shut down, plunging the
continent into deep cold.
Appendix 307
But none of the three proposed dates chime with a Heinrich Event,
says Tzedakis, whose team's research is published on Thursday by the
weekly British journal Nature.
"We can eliminate catastrophic climate change as the cause of the
Neanderthals' extinction," he said. But then what-or who-killed them?
Two rival theories are out there. One says that the Neanderthals were
slaughtered by modem humans. Another says that Neanderthals and
modem Man intermingled and even interbred. And, the distinct
Neanderthal lineage petered out.
TOI 27.11.2007
Bali Summit will emit Equivalent of 100,000 Tonnes Extra CO
Nicola Smith & Jonathan Leake
the latest UN climate change conference on the island of Bali has itself
become a major contributor to global warming.
Calculations suggest flying the 15,000 politicians, civil servants,
green campaigners and television crews into Indonesia will generate the
equivalent of 100,000 tonnes of extra CO
, That is similar to the entire
annual emissions of the African state of Chad.
Indonesian government seeing it as a chance to promote Bali as a tourist
destination after the 2002 terrorist bombings that killed 202 people.
When it was first CODI' - .;d, only a few thousand politicians, civil
servants and environmentahsts were expected to attend the conference.
The meeting, which runs from December 3 to 14, aims to create the
framework for a successor to the Kyoto treaty on reducing global
greenhouse gas emissions, which expires in 2012.
However, climate change's growing political importance has led to a
surge in interest in the conference,_ which is being held in the luxury
holiday resort of Nusa Dua on Bali's palm-fringed southern coast.
Attendees are expected to include celebrities like Leonardo DiCaprio, the
actor and Arnold Schwarzenegger, governor of California. Many are
merely "observers" who have no fonnal role to play in the talks, including
20 MEPs and 18 assistants whose itinerary includes a day-long trip to
the idyllic fishing and surfmg village of Serangan.
The UN has also recently received thousands of new registrations
from groups campaigning for the environment or fighting against poverty
308 Encyclopaedia of Petroleum Science and Engineering
WWF, one of the largest, is sending more than 32 staff to the meeting.
Thousands more are coming from businesses, especially the burgeoning
carbon trading sector.
Indonesian officials say the fmal tally could reach 20,000-and fear
it could stretch the resort's infrastructure to the limit. About 90% of the
emissions will be generated by delegates flying thousands of miles to
Chris Goodall, a carbon emissions expert, estimated each person
flying to Bali would, on average, generate the equivalent of 6.4 tonnes
of CO
If 15,000 people attend, this adds up to 96,000 tonnes of CO
this must be added about 10,000 tonnes of CO
from the conference venue
and hotels - a total of 106,000 tonnes.
Phil Woolas, British junior environment minister, is embarrassed by
the opulence of such gatherengs. "It's like a circus," he said. "It's not
just Bali. There are now more than 500 environmental treaties and
conventions taking place around the world. It's a morass of Byzantine
proportions. The UN oversees world governance on these issues and
we urgently need to streamline it."
TOI 13.11.2007
San Francisco: Intel Corp, the world's biggest microchip maker,
unveiled fast new processors on Sunday made with new techniques that
can etch circuitry nearly 200 times smaller than a red blood cell.
The chips are the first in the world to be mass-produced with a 45-
nanometer process, about one-third smaller than current 65-nanometer
technology. A nanometer is one-billionth of a meter.
"Across all segments we're increasing performance and increasing
energy efficiency" said Tom Kilroy, general manager of Intel's enterprise
Known by the project name Penryn, the chips hold little in the way
of fundamental design advances but are an important step in continuing
the industry's track record of delivering chips that get smaller and faster
every two years or so. They use a new kind of transistor-the basic
building block of microchips-that Intel unveiled earlier this year in what
was hailed as one of the industry's biggest advances in four decades.
Penryn is the "tick" in Intel's "tick-tock" strategy of shrinking an
with an all-new blueprint, known as a microarchitecture.
Appendix 309
"They are taking a successful product and making it smaller, and in
the process of making it smaller, it gets faster," said Nathan Brookwood,
principal analyst of consultant Insight 64. Brookwood said he reckoned
the new chips, to be sold under Intel's Xeon and Core 2 brands, would
be able to run most software up to 15 % faster. The 45 nanometer shift is
also important to Intel because it means the company can make more
chips from a single platter of silicon, boosting productivity and helping
recoup investment on factories, which cost about $3 billion to build.
TOI 29.9.2007
Moscow: The world's fIrs,t floating nuclear power plant will be
commissioned in 2011 in Russia's Arctic, the governor of the Arkhangelsk
Region said. '
"The construction of the fIrst such power unit with 70 MW capacity
was started this year and should be completed by 2010. The plant is
most likely to operate in Severodvinsk (in Russia's Arkhangelsk region).
Its launch is planned for 2011," Nikolai Kiselyov said. "A floating nuclear
power plant is a new product on the global market, and I hope it will be
in demand," he said.
Russia started building the plant at the Arctic port of Severodvinsk
in April, and is expected to build six more nuclear power plants of its
kind within a decade.
Earlier, a Russian nuclear offIcial said over 20 countries were
interested in buying the such plants. They are expected to be widely
used in remote regions with power shortfalls and also in the
implementation of projects requiring stand-alone and uninterrupted
electricity supplies in the absence of a developed power grid.
As India emerges into a global and economic player, it has become
an important hub for offshore software development, as well as a top
destination for overseas companies to outsource business processes
such as technical help desks, payroll management, and legal and design
Bangalore, touted as the Silicon Valley of India, is home to software
giants Wipro Technologies and Infosys Technologies Ltd, and has a
budding biotech sector.
310 Encyclopaedia of Petroleum Science and Engineering
Many expect a new wave of outsourcing, including gaming
development and health-care services, and Indian companies will be at
the forefront of these emerging trends.
The software sector was pioneered by flagship Tata Consultancy
Services Ltd in the late 1960s.-The software sector saw a 33% rise in
exports to $31.4 billion for the year to March 2007, according to the
National Association of Software and Service Companies (Nasscom). It
is expec4f< rise 24-27% to $49-$50 billion in the year to March 2008.
Outsourcing Centre
. Tata Consultancy Services Ltd is India's top software services fIrm,
followed by Infosys Technologies Ltd and Wipro Technologies Foreign
fIrms such as IBM and Accenture are also expanding in India. Software
and backoffice companies employ around 1.6 million, up from 1.3 million
last year. Indirect employment is estimated at an additional 3 million.
Indian software services companies typically make more than 50%
of their revenue from the United States.
About four-fIfths of the world's 500 largest companies already farm
out some work to India, which churns out about 2.5 million graduates
every year, though only about 15% are suitable for employment in the
Outsourcing to India can typically generate cost savings of between
35 and 50 % for foreign companies.
India's back-office services industry, which earned $8.4 billion in
exports in the year up to March, is expected to reach some $10.5 billion
in 2007-08. The United States accounts for more than two-thirds of the
outsourcing market, followed by Europe with 25%.
An average Indian graduate earns rupees 15,000 ($366) a month, but
wages are rising 10-15% a year. As of March 2007, nearly 553,000 people
were employed in more than 400 outsourcing or back-office fIrms in India.
Top outsourcing players include Genpact, WNS Global Services, IBM-
Daksh, TCS BPO, Wipro BPO, Infosys BPO, Citigroup Global Services
and MphasiS BPO.
TOI 28.8.2007
Hamburg: Two German physicists from the University of Koblenz
claim to have done the impossible by finding photons that have broken
the speed of light.
If their claims are confirmed, they will have proved wrong Albert
Einstein's special theory of relativity which requires an infInite amount
of energy to propel an object at more than 299,337.984 kilometers per
However, Gunter Nimtz and Alfons Stahlhofen say they have
possibly breached a key tenet of that theory. They say they have
conducted an experiment in which microwave photons-energetic
packets of light-travelled <instantaneously' between a pair of prisms
When the prisms were placed together, photons fIred at one edge
most of the photons reflected off the first prism they encountered
<tunnel' through the gap separating them as if the prisms were still held
Although these photons had travelled further, they arrived at their
had travelled faster than light.
The duo said being able to travel faster than light would lead to a
wide variety of bizarre consequences. For instance, an astronaut moving
faster than light would theoretically arrive at a destination before leaving,
they said.
312 Encyclopaedia of Petroleum Science and Engineering
The policy to promote ethanol usage in India has been
lagging way behind.
Ethanol can help India secure its energy future
With international crude oil prices ruling at over $70 a barrel, the
recommendation by a group of ministers that 10 per cent ethanol blending
be made mandatory across the country couldn't have come at a more
appropriate time. Such a step would help the country reduce its
dependence on oil imports and move towards greater use of renewable
resources. There's also an environmental benefit: ethanol reduces the
emission of greenhouse gases. India is one of the top 10 oil-consuming
countries in the world. The domestic production of crude oil is only 32
million tonnes as against the demand for more than 110 million tonnes.
Naturally, oil imports have a major bearing on India's trade deficit. The
expenditure on crude oil purchase is nearly Rs 1,600 billion and is only
increasing every year. Ethanol blending would help not only in alleviating
the pressure on the national exchequer, but also in lessening our
dependence on politically unstable countries in West Asia and Africa.
By blending 10 per cent ethanol, India stands to save 80 million litres of
petrol annually.
With the global sugar industry grappling with the crisis of surplus
production, and the rising output of Indian sugar contributing further to
holding the prices at record low levels, the Indian government can easily
use this opportunity to induce sugar producers to divert molasses for
the production of ethanol. The government should provide incentives
like tax breaks for ethanol producers. It could set aside a portion of the
massive oil budget for encouraging production of such renewable energy
sources. By providing such inducements, those in the business could
be persuaded to divert molasses to ethanol production rather than selling
to breweries and distilleries.
However, sugar being a cyclical industry, it is bound to see ups and
downturns. To ensure the availability of ethanol during downturns in
the industry, the government must encourage research in various
feedstocks for ethanol production. Ethanol can be made either from
fermentation of sugar or from starches like in the United States. One of
the drawbacks of sugarcane, from which ethanol is made in India, is that
it is water intensive. Hence, alternative feedstock like sweet sorghum
should be promoted for ethanol production.
Appendix 313
Simultaneously, the development of flexible-fuel vehicles must be
put on fast track. If Brazil can have vehicles running on E85 and even on
100 per cent ethanol, there is no reason why India cannot replicate the
same. E1O, nevertheless, is certainly an inspiring beginning.
From now on, every major public project, every public decision will
be judged on its effect on climate, and on its carbon cost.
We're consuming 40 per cent more than what earth can sustain
The UN's Global Environment Outlook-4 (Geo-4) warns that
consumption levels are fast depleting the world's resources, outpacing
regeneration. Earlier, the UN's Intergovernmental Panel on Climate
Change'S report cautioned that human activity-induced climate change
is causing high global temperatures that would adversely impact
developing countries the most. The UN's Human Development Report
warns that development gains could get reversed because of climate
change, resulting in greater inequities. The Geo-4 warns that ifhumanity's
ecological footprint-land and marine area needed to.regenerate what's
consumed and absorb the waste-at 21.9 hectares per person as against
earth's capacity of 15.7 hectares per person is not curbed, all would be
Carbon footprints, that measure the amount of carbon dioxide emitted
per person, are just one in India while China's is five and America's, 20.
But all reports carry the same warning: Humanity and other life forms are
at risk because of major (avoidable) environmental threats to the planet.
Geo-4 points out that environmental, developmental and energy crises
are, in fact, one large problem; they are interlinked. Which is why, as
Geo-4 suggests, we need to move the environment from the periphery to
the core of decision-making. That is, environment for development, not
development to the detriment of environment.
Despite a low per capita carbon footprint and a tradition of recycling
and conservation, India is taking small but proactive steps towards
greening production and consumption. A new building code based on a
green rating system for commercial and residential buildings to help
reduce greenhouse gas emissions has been designed by The Energy
Research Institute and approved by the government. Currently, the rating
system is to be adopted by builders voluntarily. However, with
construction booming, energy-efficient buildings ought to be mandated
314 Encyclopaedia of Petroleum Science and Engineering
by law, just as quake-resistant buildings are mandated in seismic zones.
The 13th Finance Commission will consider raising user charges for
services including irrigation, as well as tax rebates and larger share of
central resources for states adopting green practices.
However, India needs to deal with growing vehicle numbers, poor
industrial emissions standards and power plants fired by dirty coal.
China's record is worse, with proliferation of dirty power plants and skies
choking with emissions. At the forthcoming UN climate change meet in
Bali, the focus ought to be on how rich countries can reduce their deadly
footprints while transferring clean technology free of cost to countries
like India and China to help them leapfrog to sustainable development
without having to go through the entire cycle of polluting growth that
the West went through.
TOI 18.10.2007
Mumbai: On Saturday, India's first biodiesel plant will go on stream
Hyderabad-based Naturol Bioenergy will start production of the "green"
fuel at its factory in Kakinada, Andhra Pradesh.
Clean Fuel
Its entire annual production of 30 million gallons is already tied up
for exports to customers in US and Europe.
With production of biodiesel, India's place as a source of green
energy will get yet another star. Already, Pune-based Suzlon is one of
the leading players in wind energy and Delhi-based Moser Baer is setting
a large facility for making solar panels. Says Rajiv Shukla, Avendus
Advisors who is helping Naturol to raise $100 million for its expansion
Appendix 315
programme: "Though these are early days for alternative energy sources,
there is a huge opportunity in the business."
Though biodiesel fades in comparison to the performance of
gasoline, western countries are increasingly choosing the fuel. In these
days, when crude trades over $80 a barrel, biodiesel is economical.
Secondly, states like California in the US have already begun
incentivising use of alternative fuels that are low in carbon emission.
Says CS Bhaskar, managing director and CEO, Naturol: "Going forward,
we expect new regulations to increase the use of alternative fuels."
Biodiesel, an equivalent to crude derived diesel, is processed from
biological sources. Naturol will make its biodiesel from Jatropha plant
with Belgian technology. The plant derived biodiesel can be used in
normal diesel engine vehicles without modifying them, Biodiesel produces
between 40-60% lesser carbon dioxide emission but emits more smog
forming residues.
Vehicle manufacturers in Europe, who were initially vary ofbiodiesel,
are now more willing. European auto makers like Scania now say that
their vehicles can run on 100% biodiesel. Virgin's Richard Branson who
is testing the use of biodiesel in one of his trains, has planned the first
commercial flight that will be powered with a 60% biofuel-kerosene blend
in 2008.
Globally, biodiesel costs lesser than normal diesel. Its price is
benchmarked to the international prices of crude. In 2006, US and Europe
consumed nearly five million tonne of biodiesel, a negligible quantity
compared to diesel consumption. It is expected to increase to 100 million
tonne by 2016.
TOI 13.10.2007
California Astronomers Planning to Build Mammoth Telescope
Call it a small step for ET, a leap for radio astronomy. Astronomers
in Hat Creek, California, are planning to switch on the first elements of a
giant new array of radio telescopes that they say will greatly extend the
investigation of natural and unnatural phenomena in the universe.
When the Allen Telescope Array, as it is known, is complete, it will
consist of 350 antennas, each 20 feet in diameter. Using the separate
antennas as if they were one giant dish, radio astronomers will be able
to map vast swaths of the sky cheaply and efficiently. T ~ . e array will
help search for new phenomena like black holes eating each other and
316 Encyclopaedia of Petroleum Science and Engineering
so-called dark galaxies without stars, as well as eftend the search for
extraterrestrial radio signals a thousandfold, to include a million nearby
stars over the next two decades.
employing inexpensive telecommunications technology, will go into
operation. "It's like cutting the ribbon on the Nina, the Pinta and the
Santa Maria," said Seth Shostak, an astronomer at the Seti Institute, in
Mountain View" California, who. pointed out that this was the ftrst radio
telescope ever designed speciftcally for the extraterrestrial quest. The
telescope, named for Paul G Alien, who provided $25 million in seed
money, is a joint project of the Radio Astronomy Laboratory of the
University of California, Berkeley, and the Seti Institute. "If they do fmd
something, they're going to call me up ftrst and say we have a signal,"
Alien said in an interview, adding, "So far the phone hasn't rung."
Describing himself as "a child of the 50s, the golden age of space
exploration and science ftction," Allen, a founder of Microsoft, said he
fIrst got interested in supporting the search for extraterrestrial intelligence
after a conversation 12 years ago with Carl Sagan, the Cornell astronomer
and exuberant proponent of cosmic wonder.
Listening for Life: Antennas ofthe Allen Telescope Array.
When the idea later arose to build a telescope array on the cheap,
using off-the-shelf satellite dish technology and advanced digital signal
processing, Alien was intrigued. "If you know anything about me," he
said, "you know I'm a real enthusiast for new unconventional approaches
to things."
Appendix 317
Telescopes, including radio telescopes, have traditionally been
custom-built one-of-a-kind items. The antennas for the Allen array are
stamped from a mold. Allen's family foundation put up the money to get
the flrst part of the array built, with other contributions from Nathan
Myhrvold, formerly of Microsoft and the chief executive of Intellectual
Ventures in Bellevue, Wash., among others.
Leo Blitz, director of the Radio Astronomy Laboratory, estimated that
it would take three years and $41 million more, depending on the price of
aluminum, to complete the array.
The full array, astronomers say, will be useful not just for science,
but also as practice for a truly giant telescope known as the Square
Kilometer Array, which would have a combined receiving area of a square
kilometer and which astronomers hope to build in Australia or South
Africa in 10 or 20 years.
TO! 13.7.2007
London: Astronomers said on Wednesday they had discovered the
best evidence yet of water outside our own solar system-in the
atmosphere of a giant planet 60 light years from Earth.
Writing in the scientiflc journal Nature, researchers said the planet
itself, HD 189733b, was unlikely to harbour life but evidence supported
the search for life in other solar systems.
Harbouring Hope: An artist's impression ofHD 189733b and its star.
Experts said they were thrilled to have identicied clear signs of
water on the planet that is triIIions of miles away.
that is trillions of miles away," Giovanna Tinetti, a European Space Agency
fellow at the Institute d' Astrophysique de Paris in France who led the
study, was quoted as saying in an accompanying news release.
A light year is the distance a beam of light travels in one year at
300,000 km per second. The Earth's moon is only 1.3 light seconds from
318 Encyclopaedia of Petroleum Science and Engineering
our planet. "Although HD l89733b is far from being habitable, and
actually provides a rather hostile environment, our discovery shows that
water might be more common out there than previously thought, and
our method can be used in the future to study more life-friendly'
environments," Tinetti said.
Investigations showed the planet, which orbits a star in the
constellation ofVulpecula (the Fox), appeared larger at wavelength bands
that corresponded to water, suggesting the substance was present in
the atmosphere. "We fmd that absorption by water vapour is the most
likely cause of the wavelength-dependent variations in the effective
radius of the planet at the infrared wavelengths," the researchers said.
HD 189733 b is known as a "hot Jupiter" planet-like the solar
system's gas planet Jupiter but far hotter.
Subodh Vanna
As rising temperatures threaten to create floods and droughts, the UN
Human Development Report calls for steps to cut down carbon
emission by 50% over the next generation
Developed countries should cut their carbon emissions at least by
80% by the year 2050, with 20-30% cuts by 2030, if the earth has to be
saved from a complete environmental catastrophe, says the Human
Development Report (HDR) 2007 released on Tuesday.
growing economies like India and China. These steps would stabilise
equivalent concentration at 450 parts per million in the atmosphere
(currently it is 379 ppm). The cost of this process would be only 1.6% of
global GDP up to 2030. To achieve these emission targets, the report
proposes a set of policies which include carbon taxation, cap-and-trade
programmes, reduction in emission quotas, encouraging renewable energy
through economic incentives, stringent implementation of efficiency
measures in industry buildings and transport and support to breakthrough
technologies for carbon capture and storage.
The United Nations Development Programme's annual report focuses
on various aspects of human development like health, gender and poverty
every year. The 2007 report makes a strong case for action on climate
change which it calls the "defming human development issue of our
generation" .
Drawing upon the scientific evidence revealed by the
Intergovernmental Panel on Climate Change (IPCC), the UN report says
Appendix 319
that there is a small window of opportunity in this century for limiting
the global temperature increase to 2 degrees Centigrade. If this is not
done, humanity will face a series of climatic changes that will wreak havoc
on the planet. These will include flooding of coastal areas, crop failures,
epidemics, severe water scarcity, and increase in natural disasters.
In perhaps the most severe indictment of the way governments have
been handling the issue of climate change, this year's report says "the
gap between scientific evidence and political response remains large".
"The world's poor and future generations cannot afford the
complacency and prevarication that continues to characterise
international negotiations on climate change." it says, calling for a slew
of measures to hasten global cooperation on the issue.
World leaders are slated to meet in Bali, Indonesia, in December this
year to discuss measures for controlling carbon emissions. The Kyoto
Protocol which called for voluntary cuts in emissions is set to expire in
2012, but major emitters like the US and Australia have not signed it.
Through studies conducted in Ethiopia, India and elsewhere, the
HDR shows that global warming will lead to floods and droughts. The
Indian study shows that girls born during floods were less likely to attend
primary school, causing harm to their future standards of living. The
Ethiopian study shows that children born during periods of drought
continue to suffer severe health handicaps throughout their lives.
According to the report, climate change will affect the world's poor
most. Global warming will initiate droughts and flooding which will
destroy the sources of livelihood for poor people in Africa, Asia and
South America.
The poorer sections will also be the most prone to health disasters
like spread of malaria and diarrhoea. HDR 2007 also makes a strong case
for "common but differentiated responsibility" in nighting climate change
implying that the rich countries have to take the main responsibility for
controlling emissions. It identifies the "profligate consumption in rich
nations" as an ecologically unsustainable model.
It reveals that under various funds created to fight climate change,
$279 million were pledged, but only $160.4 million have been received
and a mere $26 million actually disbursed.
"Having created the problem, the world's richest countries cannot
stand aside and watch the hopes and aspirations of the world's poor
undermined by increased exposure to the risks and vulnerabilities that
will come with climate change."
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