LARLE crater

A new class of Martian impact craters have been discovered by Northern Arizona University scientist Prof Nadine Barlow and Dr Joseph Boyce from the University of Hawaii in Oct 2013. They have termed it as ‘low-aspect-ratio layered ejecta (LARLE) craters’. Prof Nadine Barlow, a scientist Northern Arizona University described this class of craters with “thin-layered outer deposit” surpassing “the typical range of ejecta”. “The combination helps vaporize the materials and create a base flow surge. The low aspect ratio refers to how thin the deposits are relative to the area they cover,” Prof Barlow said. The scientists used data from continuing reconnaissance of Mars using the old Mars Odyssey Orbiter and the Mars Reconnaissance Orbiter, discovered 139 LARLE craters ranging in diameter from 1.0 to 12.2 km, with 97 per cent of the LARLE craters are found poleward of 35N and 40S, while remaining mainly traced in the equatorial Medusae Fossae Formation.
LARLE craters are characterized by a crater and normal layered ejecta pattern surrounded by an extensive but thin outer deposit which ends in a flame-like shape. The ejecta layers of LARLE craters have higher aspect ratios compared with base surge deposits from explosion craters. This difference is probably caused by large amounts of small particles of dust and ice in the areas where LARLE craters form. This ice and dust came from mantles of snow and dust that were deposited during the many climate changes in Martian history. After the impact, deposits are quickly stabilized (order of a few days to a few years) from eolian erosion by formation of a crust formed from diffusion of water vapor out of the deposits. LARLE craters may be useful as a marker of ice under the surface.
Background.
An impact crater is an approximately circular depression in the surface of a planet, moon or other solid body in the Solar System, formed by the hypervelocity impact of a smaller body with the surface. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Impact craters range from small, simple, bowl-shaped depressions to large, complex, multi-ringed impact basins. Meteor Crater is perhaps the best-known example of a small impact crater on the Earth.
Impact craters are not to be confused with landforms that in some cases appear similar, including calderas and ring dikes.
Impact craters are the dominant geographic features on many solid Solar System objects including the Moon, Mercury, Callisto, Ganymede and most small moons and asteroids. On other planets and moons that experience more active surface geological processes, such as Earth, Venus, Mars, Europa, Io and Titan, visible impact craters are less common because they become eroded, buried or transformed by tectonics over time.
The cratering records of very old surfaces, such as Mercury, the Moon, and the southern highlands of Mars, record a period of intense early bombardment in the inner Solar System around 3.9 billion years ago. The cratering rate in the inner solar system fluctuates as a consequence of collisions in the asteroid belt that create a family of fragments that are often sent cascading into the inner solar system.
Geological history of impact craters.
The geological history of Mars can be split into many periods, but the following are the three primary periods:
Martian impact craters.
The dichotomy of Martian topography is striking: northern plains flattened by lava flows contrast with the southern highlands, pitted and cratered by ancient impacts. Research in 2008 has presented evidence regarding a theory proposed in 1980 postulating that, four billion years ago, the northern hemisphere of Mars was struck by an object one-tenth to two-thirds the size of the Moon. If validated, this would make the northern hemisphere of Mars the site of an impact crater 10,600 km long by 8,500 km wide, or roughly the area of Europe, Asia, and Australia combined, surpassing the South Pole–Aitken basin as the largest impact crater in the Solar System.
Mars is scarred by a number of impact craters: a total of 43,000 craters with a diameter of 5 km or greater have been found. The largest confirmed of these is the Hellas impact basin, a light albedo feature clearly visible from Earth. Due to the smaller mass of Mars, the probability of an object colliding with the planet is about half that of the Earth. Mars is located closer to the asteroid belt, so it has an increased chance of being struck by materials from that source. Mars is also more likely to be struck by short-period comets, i.e. those that lie within the orbit of Jupiter. In spite of this, there are far fewer craters on Mars compared with the Moon, because the atmosphere of Mars provides protection against small meteors. Some craters have a morphology that suggests the ground became wet after the meteor impacted.
Nomenclature of impact craters.
Features on Mars are named from a variety of sources. Albedo features are named for classical mythology. Craters larger than 60 km are named for deceased scientists and writers and others who have contributed to the study of Mars. Craters smaller than 60 km are named for towns and villages of the world with populations of less than 100,000. Large valleys are named for the word "Mars" or "star" in various languages; small valleys are named for rivers.


Ffestiniog Flags

The Ffestiniog Flags is a geologic formation in Wales. It preserves fossils dating back to the Cambrian period.


Ball-and-pillow structures

Ball-and-pillow structures are masses of clastic sediment that take the form of isolated pillows or protruding ball structures. These soft-sediment deformations are usually found at the base of sandstone beds that are interbedded with mudstone. It is also possible to find ball-and-pillows in limestone beds that overlie shale, but it's less common. They are normally hemispherical or kidney shaped, and range in size from a few inches to several feet.
Development and preservation.
Ball-and-pillow deformations are a result of a physical shock that has been applied to unconsolidated sediment. This shock causes rupturing to occur in the sedimentary rock layer, which induces instability. Individual lobes caused by this unstable state break off and move downward, settling into the underlying layers. There may also be a repeated lobe detachment, causing a greater downward movement into the sediments below. The "pillows" that have now been produced typically retain their original bedding compositions.
Both Kuenen (1958) and Owen (1996) have duplicated ball-and-pillow structures in the laboratory, which was done by applying a shock to multilayered strata. These experiments further conclude that earthquakes, erupting volcanoes, or meteoric impacts can create these formations.
History.
The first record of these structures was in 1916, when Smith wrote a paper called "Ball or Pillow-form Structures in Sandstones." Here he referred to these deformations as pillow-forms or ball structures. The actual term "ball-and-pillow" came from Potter and Pettijohn (1963), when they cited Smith's work incorrectly.


Valter Axelsson

Valter Axelsson (born 30 May 1924) was a Swedish geomorphologist and educator who made significant contributions to the understanding of the delta sedimentology and dynamics. One of his principal study sites was the Laitaure delta in Sarek National Park. In his thesis work on Laitaure delta and Rapaälven Axelsson drew on a hydrological data collection started by Axel Hamberg.


Lineated valley fill

Lineated valley fill (LVF), also called lineated floor deposit, is a feature of the floors of some channels on Mars, exhibiting ridges and grooves that seem to flow around obstacles. Shadow measurements show that at least some of the ridges are several metres high. LVF is believed to be ice-rich. Hundreds of metres of ice probably lie protected in LVF under a thin layer of debris. The debris consists of wind-borne dust, material from alcove walls, and lag material remaining after ice sublimated (changed from a solid directly to a gas) from a rock-ice mixture. Some glaciers on Earth show similar ridges. High-resolution pictures taken with HiRISE reveal that some of the surfaces of lineated valley fill are covered with strange patterns called closed-cell and open-cell brain terrain. The terrain resembles a human brain. It is believed to be caused by cracks in the surface accumulating dust and other debris, together with ice sublimating from some of the surfaces. The cracks are the result stress from gravity and seasonal heating and cooling. This same type of surface is present on Lobate debris aprons and Concentric crater fill so all three are believed to be related.
Lineated floor deposits began as lobate debris aprons (LDAs), which form as material leaves narrow mountain valleys and spreads out as an apron. By tracing the paths of the ridges on LDAs, researchers have come to believe that the curved ridges characteristic of lobate debris aprons straighten out to form the more or less straight ridges of LVF.
In the regions where LVF and LDAs occur, many craters have concentric crater fill: large ridges and other surfaces nicknamed brain terrain, after the surface corrugations of the human brain.
The study of lineated valley fill and other features related to debris-covered ice has been greatly aided by the abundance of data received from Mars orbiting instruments. Excellent images have been obtained from THEMIS, MOC, CTX, and HiRISE. Detailed altimetry was collected by MOLA.
The Mars Reconnaissance Orbiter's Shallow Radar gave a strong reflection from the top and base of LDAs, meaning that pure water ice made up the bulk of the formation (between the two reflections), strong evidence that the LDAs in Hellas Planitia are glaciers covered with a thin layer of rocks. Since lineated valley terrain is derived from lobate debris aprons, it probably contains buried ice—at least in places.
Connection to past climate.
Studies of LDAs and LVF give evidence that there have been multiple episodes of glaciation on Mars, including ones that produced glaciers nearing a kilometre in thickness. These ice ages are related to major climate shifts caused by major variations in axial tilt. Earth's rather large moon prevents large changes in its tilt. The two moons of Mars are tiny. So Mars undergoes large periods when its ice cap receives more direct sunlight.
During this time ice in the cap sublimates, and thick snow falls in mid-latitudes — the zones where concentric crater fill, lineated valley fill and lobate debris aprons are common. The distribution of craters on LVF indicates a late Amazonian age for at least some areas.
Where located.
Lineated valley fill is common in the middle latitudes, especially near the northern dichotomy boundary. The Nilosyrtis Mensae, Protonilus Mensae and Deuteronilus Mensae bear many examples of LVF. Ismenius Lacus quadrangle and Hellas quadrangle contain many valleys displaying lineated valley fill.
LVF and other ice-related forms are collectively known as fretted terrain, which includes winding and straight valleys with isolating plateaus and mesas.
Importance of lineated valley fill.
Studies of lineated valley fill have added evidence that the climate of Mars has undergone many large changes in the past.
At times there is snow, and at times the snow may melt. The resulting small areas of liquid water cause weathering of the rocks and may provide a favourable environment for life. Understanding lineated valley fill and other manifestations of buried ice will allow future colonists to find sources of water.
Reull Vallis, as pictured below, displays such deposits. Sometimes the lineated floor deposits show a chevron pattern which is further evidence of movement. The picture below taken with HiRISE of Reull Vallis shows these patterns.


Blaencediw Formation

The Blaencediw Formation is a geologic formation in Wales. It preserves fossils dating back to the Ordovician period.


Ty Formation

The Ty Formation is a geologic formation in Wales. It preserves fossils dating back to the Silurian period.


Freeman Silt

The Freeman Silt is a geologic formation in California. It preserves fossils dating back to the Neogene period.


Emigrant Springs Formation

The Emigrant Springs Formation is a geologic formation in Nevada. It preserves fossils dating back to the Cambrian period.


Volcanism on the Moon

Volcanism on the Moon is represented by the presence of volcanoes, pyroclastic deposits and vast lava plains on the lunar surface. The volcanoes are typically in the form of small domes and cones that form large volcanic complexes and isolated edifices. Calderas, large-scale collapse features generally formed late in a volcanic eruptive episode, are exceptionally rare on the Moon. Lunar pyroclastic deposits are the result of lava fountain eruptions from volatile-laden basaltic magmas rapidly ascending from deep mantle sources and erupting as a spray of magma, forming tiny glass beads. However, pyroclastic deposits formed by less common non-basaltic explosive eruptions are also believed to exist on the Moon. Lunar lava plains cover large swaths of the Moon's surface and consist mainly of voluminous basaltic flows. They contain a number of volcanic features related to the cooling of lava, including lava tubes, rilles and wrinkle ridges.
The Moon has been volcanically active throughout much of its history, with the first volcanic eruptions having occurred about 4.2 billion years ago. Volcanism was most intense between 3.8 and 3 billion years ago, during which time much of the lunar lava plains were created. This activity was originally thought to have petered out about 1 billion years ago, but more recent evidence suggests that smaller-scale volcanism may have occurred in the last 50 million years. Today, the Moon has no active volcanoes even though a significant amount of magma may persist under the lunar surface.
Early impressions.
In 1610, Italian astronomer Galileo Galilei misinterpreted the lunar lava plains as seas while observing the Moon through the world's first telescope. Galilei therefore dubbed them "maria" after the Latin word for "seas". The bowl-shaped depressions distributed throughout the lunar landscape were first suggested to be volcanoes in 1665 by British chemist Robert Hooke. Their volcanic origin was bolstered by their similarity to the Phlegraean Fields craters in Italy, although much larger. French astronomer Pierre Puiseux proposed that the Moon's craters were collapsed volcanic domes that had vented all their gases. Pierre Laplace, another French astronomer, added that meteorites were volcanic projectiles ejected from lunar craters during major eruptions.
The origin of lunar craters remained controversial throughout the first half of the 20th century, with volcano supporters arguing that bright rays fanning out of some craters were streaks of volcanic ash similar to those found at Mount Aso in Japan. Astronomers also reported flashes of light and red clouds over the Alphonsus and Aristarchus craters. Evidence collected during the Apollo program (1961–1972) and from unmanned spacecraft of the same period proved conclusively that meteoric impact, or impact by asteroids for larger craters, was the origin of almost all lunar craters, and by implication, most craters on other bodies as well.
Features.
After impact cratering, volcanism is the most dominant process that has modified the lunar crust. Much of this modification has been preserved due to the lack of plate tectonics on the Moon, such that the lunar surface has changed insignificantly throughout the Moon's geological history. Lunar volcanism has mostly been confined to the near side of the Moon where basaltic lava plains are the dominant volcanic feature. In contrast, positive topographic features such as domes, cones and shields represent only a tiny fraction of the lunar volcanic record. Volcanoes and lava plains have been found on both sides of the Moon.
Lava plains.
The lunar maria are large basaltic plains that cover more than 15% of the Moon's surface. They are the most obvious volcanic features on the Moon, appearing as dark topographic features when seen with the naked eye. Many tend to cover the floors of large impact basins and are therefore typically circular in outline, with some smaller maria filling the bottoms of impact craters. The major lunar maria range in size from over to about and are outclassed only by the larger Oceanus Procellarum, which has a diameter of roughly . They typically range in thickness from about , with individual lava flows ranging from thick. This suggests that each mare is the product of several overlapping eruptive events.
The ages of the mare basalts have been determined both by direct radiometric dating and by the technique of crater counting. The radiometric ages range from about 3.16 to 4.2 billion years, whereas the youngest ages determined from crater counting are about 1.2 billion years. Nevertheless, the majority of mare basalts appear to have erupted between about 3 and 3.5 billion years ago. The few basaltic eruptions that occurred on the far side of the Moon are old, whereas the youngest flows are found within Oceanus Procellarum on the near side. While many of the basalts either erupted within, or flowed into, low-lying impact basins, the largest expanse of volcanic units, Oceanus Procellarum, does not correspond to any known impact basin.
The reason that the mare basalts are predominantly located on the near-side hemisphere of the Moon is still being debated by the scientific community. Based on data obtained from the Lunar Prospector mission, it appears that a large proportion of the Moon's inventory of heat producing elements (in the form of KREEP) is located within the regions of Oceanus Procellarum and the Imbrium basin, a unique geochemical province now referred to as the Procellarum KREEP Terrane. While the enhancement in heat production within the Procellarum KREEP Terrane is most certainly related to the longevity and intensity of volcanism found there, the mechanism by which KREEP became concentrated within this region is not agreed upon.
Volcanoes.
A number of domes and cones are present on the Moon, but such features likely formed differently than those on Earth. Because gravity on the Moon is only one sixth of that on Earth, lunar volcanism is capable of throwing ejecta much further, leaving little to pile up near the vent. Instead of a volcanic cone, such lunar eruptions should form a broad, thin layer around the vent. On Earth, lava domes form from very thick, pasty lavas. Basaltic lavas are more liquid and tend to form broad, flat lava flows. On the Moon, most of the domes and cones appear to be made of basalts. As a result, they are unlikely to have formed like Earth domes from thick, non-basaltic lavas. Instead, the lunar domes and cones may mark places where the erupted basalts were just barely molten.
Lunar domes are seldomly found in isolation. Instead, they more commonly form in groups throughout the lunar lava plains. A prominent example are the Marius Hills, one of the largest volcanic complexes on the Moon. They consist of several cones and domes that occupy the summit of a broad topographic swell, which may be the lunar equivalent of a shield volcano. The complex rises from the surrounding plains and forms a lava plateau. A total of 59 cones and 262 domes ranging in diameter from have been identified.
Mons Rümker is a smaller complex similar in appearance to the Marius Hills. It comprises a plateau with an area of roughly and rises above the surrounding surface. Three main basalt units ranging in age from 3.51 to 3.71 billion years have been identified at Mons Rümker, although the youngest volcanic features may be steep-sided domes on the plateau surface as they show indications of having been active until the Eratosthenian. More than 20 domes overlie the plateau and are the most prominent volcanic landforms of Mons Rümker.
The Gruithuisen Domes in northwestern Mare Imbrium consist of two volcanic edifices: Mons Gruithuisen Gamma to the north and Mons Gruithuisen Delta to the south. They are situated on the rim of an impact crater and differ in color from the surrounding rocks. The domes may mark a rare instance of non-basaltic volcanism on the Moon. Mons Hansteen, a roughly triangular-shaped dome on the southern margin of Oceanus Procellerum, is another example of a rare non-basaltic lunar volcano. It consists of high-silica material that was erupted roughly 3.5 to 3.7 billion years ago from vents along northeast, northwest and southwest-trending fractures.
The Compton–Belkovich Volcanic Complex (CBVC) is a wide and long non-mare feature on the far side of the Moon. It differs from other lunar volcanic features due to its evolved lithology, regional tectonic setting, its location being near the north pole, far from the Procellarum KREEP Terrane and its recent association with endogenic water. In the middle of the CBVC lies an irregular-shaped depression bounded by fault scarps that is believed to be a caldera. Just to the west is a roughly wide and long feature called West Dome. A volcanic cone-like feature, called East Dome, lies near the eastern caldera margin. It has a more or less north–south trend, measuring long and wide. Just north of the caldera is a feature called Little Dome, in diameter. Further north is an elongated dome, oriented north–south, called Middle Dome. It is long and wide. Both Little Dome and Middle Dome have boulders on top that may be volcanic blocks. Big Dome, also known as North Dome, is further to the north at the edge of the CBVC. It is in diameter with a depression in the top. Small-crater size frequency distribution has given inconclusive results for the timing of CBVC volcanism, with ages ranging from less than 1 billion years to greater than 3 billion years.
Lava tubes.
Although lava tubes have long been known to exist on Earth, it has only been relatively recently that they have been confirmed to also exist on the Moon. Their existence is sometimes revealed by the presence of a "skylight", a place in which the roof of the tube has collapsed, leaving a circular hole that can be observed by lunar orbiters. An area displaying a lava tube is the Marius Hills region. In 2008, an opening to a lava tube in this area may have been discovered by the Japanese Kaguya spacecraft. The skylight was photographed in more detail in 2011 by NASA's Lunar Reconnaissance Orbiter, showing both the 65-meter-wide pit and the floor of the pit about below. There may also be lava tubes in the Mare Serenitatis.
Lunar lava tubes may potentially serve as enclosures for human habitats. Tunnels larger than in diameter may exist, lying under or more of basalt, with a stable temperature of . These natural tunnels provide protection from cosmic radiation, solar radiation, meteorites, micrometeorites, and ejecta from impacts. They are insulated from the extreme temperature variations on the lunar surface and could provide a stable environment for inhabitants.
Pyroclastic deposits.
Near the edges of the lunar mare are dark layers of material that cover many thousands of square kilometers. They contain many small spheres of orange and black glass that probably formed from small drops of lava that cooled very quickly. Such droplets are believed to be ejecta from lava fountain eruptions that were larger than those on Earth. The largest known deposits occur at Taurus–Littrow, Sinus Aestuum, Sulpicius Gallus, Rima Bode, Mare Vaporum, Mare Humorum and the Aristarchus Plateau in the central near side of the Moon.
Many smaller pyroclastic deposits measure only a few kilometers in diameter and are almost always located near the mare or in large impact crater floors, although several also lie along clear fault lines. They were likely produced by small volcanic explosions since most contain a small elongated or irregular-shaped central pit or crater. Examples are preserved along the crater floor edge of Alphonsus, an impact crater on the eastern edge of Mare Nubium.
Extending about east-southeast from the CBVC is a highly reflective area that may be a pyroclastic flow deposit. Its reflectivity is stronger in the range, indicating that quartz or alkali feldspar is the major constituent. Explosive remains also appear scattered to the east for about , covering an area of . The large extent of this pyroclastic deposit is due to the Moon's low gravity, such that a giant explosive eruption from the CBVC was able to spread debris over an area much greater than would be possible on Earth.
Rilles.
These are long, narrow depressions in the lunar surface that resemble channels. Their precise formation remains to be determined, but they were likely formed by different processes. For instance, sinuous rilles meander in a curved path like a mature river and are thought to represent lava channels or the remains of collapsed lava tubes. They normally extend from small pit structures that are believed to have been volcanic vents. Schroter's Valley between Mare Imbrium and Oceanus Procellarum is the largest sinuous rille. Another prominent example is Rima Hadley, which formed nearly 3.3 billion years ago.
Arcuate rilles have a smooth curve and are found on the edges of the dark lunar maria. They are believed to have formed when the lava flows that created a mare cooled, contracted and sank. These are found all over the Moon, prominent examples can be seen near the southwestern border of Mare Tranquillitatis and on the western southeastern border of Mare Humorum.
Impacts.
Analysis of Moon magma samples retrieved by the Apollo missions indicate that volcanism on the Moon produced a relatively thick lunar atmosphere for a period of 70 million years between 3 and 4 billion years ago. This atmosphere, sourced from gases ejected from lunar volcanic eruptions, was twice the thickness of that of present-day Mars. It has been theorized, in fact, that this ancient atmosphere could have supported life, though no evidence of life has been found. The ancient lunar atmosphere was eventually stripped away by solar winds and dissipated into space.
Partial melting of the lunar mantle and the emplacement of Oceanus Procellarum flood basalts may have caused axial tilting of the Moon 3 billion years ago, during which time the lunar poles shifted to their modern positions. This polar wander is inferred from polar hydrogen deposits that are antipodal and displaced equally from each pole along opposite longitudes.
Recent activity.
In 2014, NASA announced "widespread evidence of young lunar volcanism" at 70 irregular mare patches identified by the Lunar Reconnaissance Orbiter, some less than 50 million years old. This raises the possibility of a much warmer lunar mantle than previously believed, at least on the near side where the deep crust is substantially warmer because of the greater concentration of radioactive elements. Just prior to this, evidence has been presented for 2–10 million years younger basaltic volcanism inside the crater Lowell, located in the transition zone between the near and far sides of the Moon. An initially hotter mantle and/or local enrichment of heat-producing elements in the mantle could be responsible for prolonged activities also on the far side in the Orientale basin.


Ardengost Formation

The Ardengost Formation is a geologic formation in France. It preserves fossils dating back to the Carboniferous period.


Butterfield Formation

The Butterfield Formation is a geologic formation in Utah. It preserves fossils dating back to the Carboniferous period.


Dromaeosauripus

Dromaeosauripus is an ichnogenus that has been attributed to dinosaurs. "Dromaeosauripus" footprints have been found at Dinosaur Ridge in the United States, Bito Island Tracksite in South Korea's Bito Island, and the Hekou Group in China. "Dromaeosauripus" footprints were probably made by dromaeosaurs.
"Dromaeosauripus yongjingensis".
In 2012, "D. yongjingensis" was described from tracks in the Hekou Group. "D. yongjingensis" shows prominent toe and heel pads. Heel pads are apparently absent in other "Dromaeosauripus", probably due to behavior, preservation, and/or substrate consistency.


Dol Formation

The Dol Formation is a geologic formation in Wales. It preserves fossils dating back to the Ordovician period.


North Park Formation

The North Park Formation is a geologic formation in Wyoming. It preserves fossils dating back to the Neogene period.


Ptarmigan Formation

The Ptarmigan Formation is a geologic formation in British Columbia. It preserves fossils dating back to the Cambrian period.


Horizon a Miquelinia migueli Formation

The Horizon a Miquelinia migueli Formation is a geologic formation in France. It preserves fossils dating back to the Ordovician period.


Hordaland Formation

The Hordaland Formation is a geologic formation in Norway. It preserves fossils dating back to the Paleogene period.


Daniel Fisher (paleontologist)

Professor Daniel Fisher is a paleontologist who studies paleobiology and the extinction of mastodons. He received his Ph.D. in Geological Sciences from Harvard University in 1975 and is the Claude W. Hibbard Collegiate Professor of Paleontology and the Director of the Museum of Paleontology at the University of Michigan. His research on mammoth tusks has helped to shape the common understanding of mammoth life.
He worked as a professor in the Department of Geological Sciences at the University of Rochester until 1979 when he moved to the University of Michigan to join the Department of Geological Sciences. In 2015, he led the dig in of a gigantic mammoth from a farmer’s field in Michigan which is helping researchers to conclude about when humans first came to the Americans. He was on a NET Television-produced segment for the PBS series “NOVA scienceNOW” about Ice Age mammoths.


Back-stripping

Back-stripping (also back stripping or backstripping) is a geophysical analysis technique used on sedimentary rock sequences - the technique is used to quantitatively estimate the depth that the basement would be in the absence of sediment and water loading. This depth provides a measure of the unknown tectonic driving forces that are responsible for basin formation (otherwise known as tectonic subsidence or uplift). By comparing backstripped curves to theoretical curves for basin subsidence and uplift it is possible to deduce information on the basin forming mechanisms.
The technique developed by Watts & Ryan in 1976 allows for the recovery of the basement subsidence and uplift history in the absence of sediment and water loading and, therefore isolate the contribution from the tectonic forces responsible for the formation of a rift basin. It is a method by which successive layers of basin fill sediment are "stripped off" the total stratigraphy during analysis of that basin's history. In a typical scenario, a sedimentary basin deepens away from a marginal flexure, and the accompanying isochronous strata typically thicken basinward. By isolating the isochronous packages one-by-one, these can be "peeled off" or backstripped - and the lower bounding surface rotated upward to a datum. By successively backstripping isochrons, the basin's deepening history can be plotted in reverse, leading to clues as to its tectonic or isostatic origin. A more complete analysis uses decompaction of the remaining sequence following each stage of the back-stripping. This takes into account the amount of compaction caused by the loading of the later layers and allows a better estimation of the depositional thickness of the remaining layers and the variation of water depth with time.
General Theory.
As a result of their porosity, sedimentary strata are compacted by overlaying sedimentary layers after deposition. Consequently, the thickness of each layer in a sedimentary sequence was larger at the time of its deposition than it is when measured in the field. In order to consider the influence of sediment compaction on the thickness and density of the stratigraphic column, the porosity must be known. Empirical studies show that the porosity of rocks decreases exponentially with depth. In general we can describe this with the relationship:
where formula_1 is the porosity of the rock at depth formula_2, formula_3 is the porosity at the surface and formula_4 is a rock specific compaction constant.
Back-stripping Equation.
The fundamental equation in back-stripping corrects the observed stratigraphic record for the effects of sediment and water loading and changes in water depth, and is given by:
where formula_5 is the tectonically driven subsidence, formula_6 is the decompacted sediment thickness, formula_7 is the mean sediment density, formula_8 is the average depth at which the sedimentary units were deposited, formula_9 and formula_10 are the densities of the water and mantle respectively, and formula_11 the difference in sea-level height between the Present and the time at which the sediments were deposited. The three independent terms account for the contributions of sediment loading, water depth and sea-level oscillations to the subsidence of the basin.
Derivation.
To derive equation () one should first consider a 'loaded' column that represents a sedimentary unit accumulated over a certain geological time period, and a corresponding 'unloaded' column that represents the position of the underlying basement without the effects of the sediments. In the scenario, the pressure at the base of the loaded column, is given by:
where formula_12 is the water depth of deposition, formula_4 is the mean thickness of the crust, formula_14 is the sediment thickness corrected for compaction, formula_15 is the average gravity and formula_16,formula_17 and formula_18 are the densities of water, the sediment and the crust respectively.
The pressure at the base of the unloaded column is given by:
where formula_5 is the tectonic or corrected subsidence, formula_20 is the density of the mantle, and formula_21 is the distance from the base of the unloaded crust to the depth of compensation (which is assumed to be at the base of the loaded crust) and is given by:
Substitution of (),() and () after simplifying, we obtain ().
Multi-layer Case.
For a multi-layered sedimentary basin, it is necessary to successively back-strip each individually identifiable layer separately to obtain a complete evolution of the tectonic subsidence. Using equation (),a complete subsidence analysis is performed by stepwise removal of the top layer at any one stage during the analysis and performing back-stripping as if for a single layer case. For the remaining column, mean densities and thickness must be used at each time, or calculation, step. Equation () then becomes the tectonic amount of subsidence during sedimentation of the top most layer only. In this case formula_22 and formula_23 can be defined as the thickness and density of the entire remaining sedimentary column after removal of the top layer formula_24 (i.e. the decompacted thickness). The thickness of a sediment pile with formula_24 layers is then:
The density of the sedimentary column underneath layer formula_24 is given by the mean density of all the remaining layers. This is the sum of all the densities of the remaining layers multiplied by the respective thickness and divided by formula_27:
Effectively you iteratively apply () and () using formula_27 and formula_29 instead of formula_30 and formula_23.


Solvik Formation

The Solvik Formation is a geologic formation in Norway. It preserves fossils dating back to the Silurian period.


Primitive rock


Havensville Formation

The Havensville Formation is a geologic formation in Kansas. It preserves fossils dating back to the Permian period.


Lamprophyre

Lamprophyres (Greek λαμπρός (lamprós) = "bright" and φύρω (phýro) = to mix) are uncommon, small volume ultrapotassic igneous rocks primarily occurring as dikes, lopoliths, laccoliths, stocks and small intrusions. They are alkaline silica-undersaturated mafic or ultramafic rocks with high magnesium oxide, >3% potassium oxide, high sodium oxide and high nickel and chromium.
Lamprophyres occur throughout all geologic eras. Archaean examples are commonly associated with lode gold deposits. Cenozoic examples include magnesian rocks in Mexico and South America, and young ultramafic lamprophyres from Gympie in Australia with 18.5% MgO at ~250 Ma.
Petrology.
Modern science treats lamprophyres as a catch-all term for ultrapotassic mafic igneous rocks which have primary mineralogy consisting of amphibole or biotite, and with feldspar in the groundmass.
Lamprophyres are not amenable to classification according to modal proportions, such as the system QAPF due to peculiar mineralogy, nor compositional discrimination diagrams, such as TAS because of their peculiar geochemistry. They are classified under the IUGS Nomenclature for Igneous Rocks (Le Maitre et al., 1989) separately; this is primarily because they are rare, have peculiar mineralogy and do not fit classical classification schemes. For example, the TAS scheme is inappropriate due to the control of mineralogy by potassium, not by calcium or sodium.
Mitchell has suggested that rocks belonging to the "lamprophyre facies" are characterized by the presence of phenocrysts of mica and/or amphibole together with lesser clinopyroxene and/or melilite set in a groundmass which may consist (either singly or in various combinations) of plagioclase, alkali feldspar, feldspathoids, carbonate, monticellite, melilite, mica, amphibole, pyroxene, perovskite, Fe-Ti oxides and glass.
Classification schemes which include genetic information, may be required to properly describe lamprophyres.
Genesis.
Rock considered lamprophyres are part of a "clan" of rocks, with similar mineralogy, textures and genesis. Lamprophyres are similar to lamproites and kimberlites. While modern concepts see orangeites, lamproites and kimberlites as separate, a vast majority of lamprophyres have similar origins to these other rock types.
Mitchell considered the lamprophyres as a "facies" of igneous rocks created by a set of conditions (generally; late, highly volatile differentiates of other rock types). Either scheme may apply to some, but not all, occurrences and variations of the broader group of rocks known as lamprophyres and melilitic rocks.
Leaving aside complex petrogenetic arguments, it is fair to say that the essential components in lamprophyre genesis are;
Individual examples thus may have a wide variety of mineralogy and mechanisms for formation. Rock considered lamprophyres to be derived from deep, volatile-driven melting in a subduction zone setting. Others such as Mitchell consider them to be late offshoots of plutons, etc., though this can be difficult to reconcile with their primitive melt chemistry and mineralogy.
Petrography.
 Lamprophyres are a group of rocks containing phenocrysts, usually of biotite and amphibole (with bright cleavage surfaces), and pyroxene, but not of feldspar. They are thus distinguished from the porphyries and porphyrites in which the feldspar has crystallized in two generations. They are essentially dike rocks, occurring as dikes and thin sills, and are also found as marginal facies of plutonic intrusions. They are usually dark in color, owing to the abundance of ferro-magnesian silicates, of high specific gravity and liable to decomposition. For these reasons they have been defined as a melanocrate series (rich in the dark minerals); and they are often accompanied by a complementary leucocrate series (rich in the white minerals feldspar and quartz) such as aplites, porphyries and felsites.
Biotite (usually phlogopite) and amphibole (usually pargasite or other magnesian hornblende) are panidiomorphic; all are euhedral, well formed. Feldspar is restricted to the ground mass. In many lamprophyres the pale quartz and felspathic ingredients tend to occur in rounded spots, or ocelli, in which there has been progressive crystallization from the margins towards the center. These spots may consist of radiate or brush-like feldspars (with some phlogopite and hornblende) or of quartz and feldspar. A central area of quartz or of analcite probably represents an original miarolitic cavity infilled at a later period.
The presence or absence of the four dominant minerals, orthoclase, plagioclase, biotite and hornblende, determines the species:
These rocks contain also iron oxides (usually titaniferous), apatite, sometimes sphene, augite, and olivine. The hornblende and biotite are brown or greenish-brown, and as a rule their crystals even when small are very perfect and give the thin section views an easily recognizable character. Green hornblende occurs in some of these rocks. Augite exists as euhedral crystals of pale green color, often zonal and readily weathering. Olivine in the fresh state is rare; it forms rounded, corroded grains; in many cases it is decomposed to green or colorless hornblende in radiating nests (pilite). The plagioclase occurs as small rectangular crystals; orthoclase may have similar shapes or may be fibrous and grouped in sheaf-like aggregates that are narrow in the middle and spread out towards both ends. As all lamprophyres are prone to alteration by weathering a great abundance of secondary minerals is usually found in them; the principal are calcite and other carbonates, limonite, chlorite, quartz and kaolin.
Ocellar structure is common; the ocelli consist mainly of orthoclase and quartz, and may be up to one quarter of an inch in diameter. Another feature of these rocks is the presence of large foreign crystals, or xenocrysts, of feldspar and of quartz. Their forms are rounded, indicating partial resorption and the quartz may be surrounded by corrosion borders of minerals such as augite and hornblende produced where the magma is attacking the crystal.
Lamprophyres (including minette) traditionally have been defined as:
On a purely chemical basis, an extrusive lamprophyre (sp. "minette") might be classified as potassic trachybasalt, shoshonite, or latite using the total alkali-silica diagram (see TAS classification), or as absarokite, shoshonite, or banakite using a classification sometimes applied to potassium-rich lavas. Such chemical classifications ignore the distinctive textures and mineralogies of lamprophyres.
Nomenclature.
The naming and classification of lamprophyres has had several revisions, and much argument within the geological community. Nicholas Rock and colleagues devoted much time to a complicated descriptive system of nomenclature which took after a series of nomenclature based on regional examples of the very diverse mineralogical expression of lamprophyres. This system was based on a somewhat provincial, rustic system of naming after French villages nearby were found the first described examples of various species of lamprophyre (Vosges being the prime example).
Modern nomenclature has been derived from an attempt to constrain some genetic parameters of lamprophyre genesis. This has, by and large, dispensed with the previous provincial names of lamprophyre species, in favor of a mineralogical name. The old names are still used for convenience.
Vogesite.
Vogesite was first described from the Vosges mountains, France, where rocks of this type (actually, minette) were described in the early 20th century.
Minette.
A historical view of minette was provided by Johannsen (1937). He wrote that the name was " ... used by the miners in the Vosges apparently for oolitic or granular iron ore, and possibly derived from the valley of Minkette, where it occurs..."
Examples include minettes in the Navajo Volcanic Field (e.g. dikes near Shiprock and Mitten Rock, NM) of the Colorado Plateau and in the Mexican Volcanic Belt.
Kersantite.
Kersantite is named after the village of Kersanton, Brittany, France, where the rock was first identified. An obsolete name for kersantite is kersanton.
Distribution.
Lamprophyres are usually associated with voluminous granodiorite intrusive episodes. They occur as marginal facies to some granites, though usually as dikes and sills marginal to and crosscutting the granites and diorites. In other districts where granites are abundant no rocks of this class are known. It is rare to find only one member of the group present, but minettes, vogesites, kersantites, etc., all appear and there are usually transitional forms.
Lamprophyres are also known to be spatially and temporally associated with gold mineralisation, for example orogenic gold deposits. Rock (1991) considered lamprophyres to be possible source rocks for the gold, but this view is not generally supported. The more reasonable explanation for the correlation is that lamprophyres, representing "wet" melts of the asthenosphere and mantle, correlate with a period of high fluid flow from the mantle through the crust, during subduction-related metamorphism, which drives gold mineralisation.
Non-melilitic lamprophyres are found in many districts where granites and diorites occur, such as the Scottish Highlands and Southern Uplands of Scotland; the Lake District of northwest England; Ireland; the Vosges Mountains of France; the Black Forest and Harz mountain regions of Germany; Mascota, Mexico; Jamaica and in certain locations of British Columbia, Canada.


Hurricane Fault

The Hurricane Fault is an intracrustal seismic fault that runs along the boundary between the Colorado Plateau block and the Basin and Range geologic province of western North America. It is a 250-km-long, north-south striking, high-angle, down-to-the-west normal fault, running from about Cedar City, Utah southward into northwestern Arizona. The fault is named for the community of Hurricane.
The 1992 St. George earthquake (magnitude 5.8), which triggered a damaging landslide, has been attributed to the Hurricane Fault.


Rift zone

A rift zone is a feature of some volcanoes, especially shield volcanoes, in which a set of linear cracks (or rifts) develops in a volcanic edifice, typically forming into two or three well-defined regions along the flanks of the vent. Believed to be primarily caused by internal and gravitational stresses generated by magma emplacement within and across various regions of the volcano, rift zones allow the intrusion of magmatic dykes into the slopes of the volcano itself. The addition of these magmatic materials usually contributes to the further rifting of the slope, in addition to generating fissure eruptions from those dykes that reach the surface. It is the grouping of these fissures, and the dykes that feed them, that serves to delineate where and whether a rift zone is to be defined. The accumulated lava of repeated eruptions from rift zones along with the endogenous growth created by magma intrusions causes these volcanoes to have an elongated shape. Perhaps the best example of this is Mauna Loa, which in Hawaiian means "long mountain", and which features two very well defined rift zones extending tens of kilometers outward from the central vent.
Formation.
Rift zones are characterized by the close grouping of intrusive dykes and extrusive fissures extending outward along a relatively narrow band from the area of a central vent. The internal extensional forces and isostatic loading generated by intruding magma volumes (either associated with the magma chamber or subsequent dyke and sill formation extending outward from that chamber), in conjunction with accumulation of erupted materials, contribute to the mass and slope of the forming edifice. It is the weight of the edifice exceeding its material strength, with the additional stresses of the magma inflating the internal regions of the edifice, that can generate the initial cracking around a developing volcanic summit. Additionally, tectonic activity such as normal faulting is also commonly associated with formation of rifts along volcanic flanks. Following the path of least resistance, subsequent magmatic dykes form along and within these initial cracks, causing additional stresses to be imparted to the local materials of the edifice, which in turn generate new rifts for the magma to flow towards. In this way, established rift zones can potentially be self-sustaining geologic features along the flanks of the given volcanic vent.
The orientation of this rifting is largely dependent on the gravitational and tectonic stresses at play. Basaltic shield volcanoes typically feature two main rift zones, situated with angles of 120° between in ideal situations. On shield volcanoes forming from level seafloor without neighboring vents, flank rifting occurs more evenly distributed around the vent. However, where the flanks of a volcano may be supported on one side by the presence of a pre-existing feature, or burdened with various planes of weakness, rift zone formation promulgates according to down-slope pull of gravity.
Structure.
The infill of magmas in the form of dykes helps to define the shape of a volcano. A higher frequency of intrusive events along rift zones leads to elongated topographies of the affected edifices. Mathematical models show how the presence of rift zones contributes to a central horizontal bulge or ridge parallel to the orientation of the rifts. This same modelling shows how this central bulge is dependent on the ratio between rift zone length and depth of the magma sources, with longer fissures over shallower sources being more positively associated with very elongated topographies of the associated flanks.
Occasionally, fissure eruptions associated with rift zones can actually evolve into new vents along the volcanic edifice, generating lava flows lasting for months or longer. These lava flows add surface materials to the slopes of the volcano, extending the slopes outward in a general flattening of the morphology of the flank. The extensional character of these events can contribute to flank instability and mass wasting events where whole sections of the volcanic edifice can collapse along rift zone boundaries. These mass wasting events can affect the dyke formations and orientations as the mass of the edifice shifts, which can have profound impacts on the structural development of the edifice, while also potentially creating many volcanic hazards, such as tsunamis and dramatic shifts in directions of lava flows, to unsuspecting communities.
Volcanologist George P.L. Walker stated that rift zones were common in most volcanoes around the world, regardless of their type and formation. Walker put forward the idea that, absent any obvious signs of rifting on the surface, the presence of other volcanic features that are also associated with dyke intrusions (such as elongated cinder cones and linearly-aligned fissure vents) should also be taken to represent the presence of a rift zone-like processes in the given region. Therefore, rift zones of various lengths and widths can be tentatively identified on many stratovolcanoes and monogenetic lava fields in addition to classic Hawaiian shield volcanoes.


Llanfawr Mudstone

The Llanfawr Mudstone is a geologic formation in Wales. It preserves fossils dating back to the Ordovician period.


Cochise Formation

The Cochise Formation is a geologic formation in Arizona. It preserves fossils dating back to the Permian period.


Hans Stern

Hans Stern (October 1, 1922 – October 26, 2007) was a Brazilian jeweler and businessman. He was dubbed the "king of the colored gems" by "The New York Times" and acclaimed by the international media. Founder of world-renowned luxury jewelry brand H.Stern.
Early life.
Stern was born in Essen, Germany, on October 1, 1922, to a Jewish family. He immigrated from Germany to Brazil at the outbreak of World War II, a couple of years prior to the Holocaust, at the age of 17.
Career.
Stern started his career in the gemstone industry when he began working at the Rio de Janeiro-based company, Cristab, which exports precious stones and minerals from Brazil. Stern traveled to Minas Gerais state as part of his job, where he came to know the local miners. He also became familiarized with many of the precious stones that were mined in the area, including topazes, tourmalines and amethysts. He became fascinated by the vibrant gems of Brazil and decided to promote them internationally, targeting foreign travelers. In doing so, he gave birth to a new industry.
Stern founded his company, H. Stern, in 1945, in order to market Brazilian gems There was no real market for Brazilian gemstones at the time. His company would eventually grow into a multinational jewelry empire. Stern and his company trained a large number of young Brazilian jewelers as H. Stern gained customers and market credibility. His work propelled the Brazilian jeweler industry up to international standards. Stern was also the first to create a worldwide warranty certificate, and to offer tours of his workshops to present the creative and production process with integrity and transparency. One of his main goals in life was achieved when important international gemological institutes revised the old "semi-precious" definition of colored stones and began referring to them since as "precious colored stones". Stern coined the phrase, "There is no semi-precious stone as there is no semi-pregnant woman or semi-honest man".
Stern's company, H. Stern, grew into a retail chain of more than 160 stores throughout the world. The first international boutiques appeared in Frankfurt, Lisbon and New York City in the 1970s. For many decades the company focused its creations on Hans' beloved colored gems, although Stern also won several Diamonds International Awards and other prizes for "avant garde" diamond designs.
Always a visionary, Stern led the business to another phase of international expansion by entering in the Basel Jewelry and Watch Fair in Basel, Switzerland, in 2003 for the first time. From the jewelry and watch fair, he was able to establish a growing network of contacts and partnerships throughout Europe, the United States and the Middle East adding another 150 points of sale to the network, through retail partnerships with department stores and specialty retailers.
As of late 2007, there are now 160 stores which are family owned and operated in 13 countries, and 150 shop in shops in another 19 countries Hans' jewelry and gemstones have been featured in a number of international fashion magazines, such as "Vogue", "Marie Claire" and "Elle". His gems are often worn by celebrities. The H. Stern jewelry line is also now sold in upscale stores in cities as far away from Brazil as Frankfurt, New York City, Paris, Moscow, Mexico City, and Tel Aviv.
Stern's favorite gemstone was the tourmaline, a stone which is commonly found throughout Minas Gerais.
Death.
Hans Stern died on October 26, 2007, in Rio de Janeiro at age 85. Stern had been hospitalized for days before his death. He was survived by his wife, Ruth, whom he married in 1958. Together the couple had four sons - Roberto, Ricardo, Ronaldo and Rafael.


Butte Creek Formation

The Butte Creek Formation is a geologic formation in Oregon. It preserves fossils dating back to the Neogene period.


Mont Saint-Hilaire

Mont Saint-Hilaire (in English: Mount Saint-Hilaire) (in Abenaki: Wigwômadenizibo), ("see names of mont Saint-Hilaire for other names") is an isolated hill, high, in the Montérégie region of southern Quebec. It is about thirty kilometres east of Montreal, and immediately east of the Richelieu River. It is one of the Monteregian Hills. Around the mountains are the towns of Mont-Saint-Hilaire and Saint-Jean-Baptiste. Other nearby towns include Otterburn Park, Beloeil and McMasterville.
The area surrounding the mountain is a biosphere reserve, as one of the last remnants of the primeval forests of the Saint-Lawrence valley. Most of the mountain is currently the property of McGill University, as the "Gault Nature Reserve", which is considered the third McGill campus. The University has opened the western half of the mountain to visitors (at a fee) for hiking and cross-country skiing, as the "Milieu Naturel" (natural area). The eastern half, or "Milieu de Conservation" (preservation area) is not accessible to the general public.
Until the late nineteenth century, the lack of information on more remote summits of Quebec, as well as the relatively high prominence (about ) of Mont Saint-Hilaire, led to it being mistaken as the highest summit in Québec. In actuality, Saint-Hilaire's 414 metres falls far short of making it the highest mountain in Quebec.
Mont Saint-Hilaire is home to a wide variety of fauna and flora, as well as a number of rare minerals, including some which were discovered on the mountain and some which are unique to the region. These minerals are exploited by a quarry on the north-eastern side of the mountain. In addition, the soil is ideal for the growth of apple trees, and the mountain's apple orchards draws tens of thousands of visitors each year.
Geography.
The mountain stands above the sea level, or 400 metres above the surrounding plains. It has several summits, surrounding a central lake, "Lac Hertel" (Lake Hertel).
Most of the well-known summits of the mountain are in the western (open to the public) part. They are the "Pain de Sucre" (Sugar Loaf), high, the Sunrise, high, the "Rocky", high, and the "Sommet Dieppe" (Dieppe Summit), high as well as "Burnt Hill"( high).
The summits of the eastern half of the mountain, which is closed to the public, are generally little known, to the point that most official maps fail to identify the distinct summits at all. Only a few names are known, such as "East Hill" and "Lake Hill". These summits range from in elevation.
Cliffs.
The best-known feature of the mountain is the cliffs. Collectively known as the "falaise dieppe", or "falaise de Dieppe" (Dieppe cliffs) the cliffs are part of the Dieppe summit, and nearly high. Some of the best known features of the cliffs include the 60-metre high "Tour rouge" (Red tower), as well as two slabs, the "Dalle noire" (Black slab) and "Dalle Verte" (Green slab), which rise at a 75-degree angle.
The cliff's unique ecosystem hosts lichens, as well as cedar trees, some of which may be as much as five hundred years old. It also hosts the mountain's population of peregrine falcons. However, the action of rock climbers has proven destructive to the ecosystem, in addition to being dangerous to the climbers themselves. A white cross on the cliff commemorates the death of a boy scout in 1941.
Lac Hertel.
At the centre of the mountain is Lac Hertel, a lake in a glacially-formed depression in the middle of the various summits. It covers an area of 0.3 square kilometre (0.12 square mile), and has a maximum depth of . It is fed by three permanent streams; a fourth flows from the lake toward the Richelieu River. The lake serves as a secondary reservoir of drinking water to the region, and, as such, swimming, fishing and boating are forbidden.
The central position of the lake on the mountain has led to claims that Mont Saint-Hilaire is a volcanic caldera. However, the lake is actually the result of glacial erosion, and in no way an ancient volcanic crater.
Geology.
Mont Saint-Hilaire is one of the Monteregian Hills, a group of erosional remnants of intrusive mountains spread across southern Quebec. It is composed of three distinct plutonic intrusions that formed during the Cretaceous Period between 133 and 120 million years ago. Like the other Monteregian Hills, Mont Saint-Hilaire forms part of the Great Meteor hotspot track, which was created when the North American Plate slid over the New England hotspot. During this time, melting occurred, creating subsurface magma intrusions. Erosion of the surrounding softer sedimentary rocks revealed the more resistant rocks of Mont Saint-Hilaire.
Mineral wealth.
Mont Saint-Hilaire is a famous mineral locality because of its great number of rare and exotic mineral species. Annite (iron rich biotite) from Mont Saint-Hilaire is among the most iron-rich found in nature. In the gabbro, biotite is less iron-rich, has lower manganese content, but is titanium-rich. Phlogopite is found as small metamorphic crystals in marble xenoliths within the syenite. Siderophyllite, a relatively rare mineral, occurs as large crystals in a metasomatised albite-rich albitite dike.
In addition to gabbro, the second intrusive suite included nepheline syenite, diorite and monzonite. The third intrusive occupies the eastern side and is mainly peralkaline nepheline syenites and porphyrites. The most mineralogically interesting are the associated agpaitic (alkali rich, low aluminium and silicon) pegmatites, the intrusive breccias, and the hornfels derived from the metasomatised sedimentary wall rocks. There have been over 366 distinct species of minerals collected at Mont Saint-Hilaire, 50 of which have this site as type locality.
Ecology.
As the last remnant in Quebec of the ancient Gulf of St. Lawrence lowland forests, the area has been a provincial biosphere reserve since 1978 and a federal Migratory Bird Sanctuary since 1960. The area hosts 21 at risk and two endangered species of plant under current statutes.
History.
The mountain, particularly the "Pain-de-Sucre" summit, was well known by the Algonquin First Nations, who used it as a vantage point to survey the valley of the Richelieu River below. The mountain is located in Abenaki traditional territory and its name, Wigwômadenizibo, which means little house-shaped mountain.
The first European to visit the region was Samuel de Champlain, who explored the Richelieu River in two expeditions in 1603 and 1609. It was during the later expedition that he discovered the mountain.
Development of the region.
Settlement around the mountain began in 1694 when a seigneury was granted to Jean-Baptiste Hertel de Rouville. A village slowly grew on the slopes of the mountain, near the streams emptying out of Lake Hertel. The combination of sugar bushes, the orchards alongside the mountain slopes, and the stream flowing from Lake Hertel which facilitated the construction of watermills provided for growth of the village in the eighteenth and early nineteenth centuries.
In the nineteenth century, the mountain became a tourist destination, particularly after Tomas Edmond Campbell bought the seigneury from the Hertel de Rouville family in 1844. A café, the Campbell Café, was established in 1851, and in 1874, a 150-room hotel, the Iroquois Hotel. Both burned down, the café in 1861 and the hotel in 1895. The tourist value of the mountain dwindled as development of the Eastern Townships made the northern Appalachians more accessible.
The Gault Reserve.
Campbell sold the mountain in 1913 to Andrew Hamilton Gault. While he saw to the development of the region, Gault also insisted on protecting the wild nature of Mont Saint-Hilaire, where he planned to build a mansion home for his retirement. Construction of the mansion began in 1957, but Gault lived there a mere three weeks before he died. He bequeathed the property to McGill University, where he had received his education, which made it into the "Gault Reserve".
The natural value of the mountain led to its being proclaimed a migratory bird sanctuary in 1960. In 1970, the mountain was divided into a preservation area, closed to the public, and an area open to the public, which became the responsibility of the "Centre de Conservation de la Nature" (Nature Conservation Centre) in 1972. In 1978, the mountain was made the first world biosphere reserve of Canada as a result of it being the last remnants of the primeval forests of the Saint-Lawrence Valley.
Although initial documents indicate the biosphere reserve covered large areas surrounding the mountains, it appears that today, the effective definition of the biosphere reserve corresponds to that of the Gault Reserve.
Names of Mont Saint-Hilaire.
In the modern Abenaki language, Mont Saint-Hilaire is known as Wigwômadenizibo, meaning the small house-shaped mountain. The neighbouring Mount Yamaska is similarly referred to in Abenaki as Wigwômadenek (Wigwam-shaped mountain), without the diminutive suffix. The mountain was formerly rendered by Europeans as Wigwomadensis (Wigwam-shaped mountain).
When Samuel de Champlain visited the mountain, he named it "Mont Fort" (which can be interpreted as "Fort Mountain" or "Mount Strong").
The establishment of the town and parish of Chambly to the south led to the mountain temporarily becoming "Mont Chambly" in the later seventeenth century (although the name persisted in English until at least 1830). After 1697, the mountain became known as "Mont Rouville", after the newly established seigneury of the Hertel de Rouville family.
When the Campbell family replaced the Hertel de Rouville family, the mountain took up the name "Mont Beloeil", after the nearby municipality of Beloeil, on the other side of the Richelieu River. However, the name Mont Saint-Hilaire, after the parish of Mont-Saint-Hilaire established at the foot of the mountain, became prevalent by the early twentieth century. Even so, quarrels between inhabitants of Beloeil and Mont-Saint-Hilaire, both near the mountain, as to which the mountain should be named after lasted well into the twentieth century, with the town newspapers of Beloeil attempting to resurrect the debate as late as 1986.
Mont Saint-Hilaire in culture.
Mont Saint-Hilaire, owing to its stark form, has always played a significant part in the culture of the nearby region. It is an important regional icon, its silhouette appearing in the symbols of many towns and cities of the region, such as Beloeil, McMasterville, Mont-Saint-Hilaire and Otterburn Park.
In art.
Several artists have painted Mont Saint-Hilaire over the years. The first was the English painter John Bainbrigge, who made three separate watercolour paintings of the mountains around 1838, while garrisoned in the region. A few decades later, the mountain also appeared in a painting by Cornelius Krieghoff.
However, the famous artists most closely linked with the mountains are the three who were born or lived in Mont-Saint-Hilaire itself over the course of the late nineteenth and twentieth century: Ozias Leduc, born in 1864 in Mont-Saint-Hilaire, his student Paul-Émile Borduas, also born in Mont-Saint-Hilaire in 1905, and finally, Jordi Bonet, who, after emigrating to Québec, settled down at Mont-Saint-Hilaire in 1969. Leduc especially is known for his numerous representations of the mountain in several paintings such as "L'Heure Mauve" and "Neige Dorée", but the mountain also inspired the work of Borduas, such as his "Le Trou des Fées" and "Synthèse d'un paysage de Mont-Saint-Hilaire", and Bonnet, who included the silhouette of the mountain in several of his works.
In religion.
Some evidence suggests that Mont Saint-Hilaire, particularly the "Pain de Sucre" summit, was a sacred site of the Algonquin natives, who conducted rituals there.
Despite a slow establishment in the region (the first two parishes at the foot of the mountain, Saint-Jean-Baptiste and Saint-Hilaire, were only established in 1796 and 1798), the Catholic Church soon established itself on the mountain. In 1841, a great wooden cross was built atop the mountain, more than high and across, with a chapel at its base. The cross was hollow, allowing visitors to climb to the top. A winding trail was established leading up to the mountain, with stations of the cross along the way. The cross was destroyed in a storm in 1846. It was replaced in 1871 by a stone chapel, which burned in 1876.
In legends.
Oral tradition in the area surrounding Mont Saint-Hilaire has recorded several legends concerning the mountains. Local figures such as the painter Ozias Leduc and local historians Armand Cardinal and Pierre Lambert have set down in writing several of those legends; even so much of the oral tradition is now lost.
Legends of the mountain generally centre on the figures of either the mountain's three fairies, who are said to have lived in a cave in the cliff-face for several centuries before abandoning the mountain and their immortality to marry their mortal lovers, or the devil, and the existence of two passage to hell, including the location known as "les Portes de fer" (the Iron gates) (two great stone slabs found next to one another on the slopes of the mountain).
Lac Hertel is also at the centre of several legends. According to different legends, it is either bottomless, connected by underground passages to Lake Champlain, or was formed as a direct result of the devil successfully convincing several of the early settlers to abandon their promise to attend mass at the newly established chapel every Sunday.
Another legend, based on the unusual ice patterns found on the northern cliff-face of the mountain, where a vaguely horse-shaped ice formation does not melt until late in the spring, state that the spirit of a local farmer's horse warns farmers against planting their crop so long as the ice formation remains on the mountain.
In esotericism.
Since the late twentieth century, the mountain has become a major hub of alleged supernatural activity. The towns surrounding the mountain have shown the highest number of UFO sightings in Quebec. The Ufologist organisation UFO-Québec has claimed Mont Saint-Hilaire to be the central hub of all UFO observations in southern Quebec. On the night of May 22–23, 1981, several hundred people came to the mountain after Richard Glenn claimed to have been warned of UFO visits to the mountain that night. The observations were severely limited by a rainstorm, although some alleged sightings still took place. Glenn also introduced the concept of the hollow earth to the mountain, claiming Mont Saint-Hilaire to be an entrance leading to the domain of the inhabitants of the hollow earth.
The abundance of unusual minerals and crystals at Mont Saint-Hilaire, as well as the effect of its mass upon local magnetism, have also been of great interest to followers of the New Age movement and conspiracy theories.


Monarch Mill Formation

The Monarch Mill Formation is a geologic formation in Nevada, United States. It preserves fossils dating back to the Neogene period.


Bedform

A bedform is a feature that develops at the interface of fluid and a moveable bed, the result of bed material being moved by fluid flow. Examples include ripples and dunes on the bed of a river. Bedforms are often preserved in the rock record as a result of being present in a depositional setting. Bedforms are often characteristic to the flow parameters, and may be used to infer flow depth and velocity, and therefore the Froude number.
Bedforms Initiation.
Bedforms are omnipresent in many environments (e.g., fluvial, eolian, glaciofluvial, deltaic and deep sea), although there is still some debate on how they develop. There are two separate, though not mutually exclusive, models of bedform initiation: defect initiation and instantaneous initiation.
Defect Initiation.
The defect theory proposes that the turbulent sweeps that are generated in turbulent flows entrain sediment that upon deposition generates defects in a non-cohesive material. These deposits then propagate downstream via a flow separation process, thus developing bedform fields. The origin of the defects is thought to be linked to packets of hairpin vortex structures. These coherent turbulent structures give rise to entrainment corridors on the mobile bed, forming grain lineations that interact with the low-speed streaks generating an agglomeration of grains. Once a critical height of grains is reached, flow separation occurs over the new structure. Sediment will be eroded close from the reattachment point and deposited downstream creating a new defect. This new defect will thus induce formation of another defect and the process will continue, propagating downstream while the accumulations of grains quickly evolve into small bedforms.
Instantaneous Initiation.
In general, the defect propagation theory plays a bigger role at low sediment transport rates since for high rates defects maybe washed away and bedforms generally initiated across the entire bed spontaneously. Venditti et al. (2005) report that instantaneous initiation begins with the formation of a cross-hatch pattern, which leads to chevron-shaped forms that migrate independently of the pattern structure. This chevron-like structure reorganizes to form the future crest lines of the bedforms. Venditti et al. (2006), based on the earlier model by Liu (1957), proposed that instantaneous initiation is a manifestation of an interfacial hydrodynamic instability of Kelvin-Helmholtz type between a highly active pseudofluid sediment layer and the fluid above it. In addition, Venditti et al. (2005) imply that there is no linkage between the instantaneous initiation and coherent turbulent flow structures, since spatially- and temporally-random events should lock in place to generate the cross-hatch pattern. Moreover, there is no clear explanation of the effect of turbulence in the formation of bedforms since bedforms may also occur under laminar flows . It is important to note, that laminar-generated bedform studies used the temporally-averaged flow conditions to determine the degree of turbulence, indicating Reynolds number in the laminar regime. However, instantaneous process, such as burst and sweeps, which are infrequent at low Reynolds number but still present, can be the driving mechanisms to generate the bedforms. The generation of bedforms in laminar flows is still a topic of debate within the scientific community, since if true, it suggests that there should be other processes for defect development other than the one suggested by Best (1992). This alternative model for bedform development at low sediment transport rates should explain the generation of defects and bedforms for cases where the flow is not turbulent.
Bedform phase diagrams.
Phase or stability diagrams are defined as graphs that show the regimes of existence of one or more stable bed states. The stability of the bed can be defined when the bedform is in equilibrium and does not change in time for the same flow condition. This invariance over time must not be confused with a static morphology or frozen equilibrium; on the contrary, the bed moves and adjusts in a dynamic equilibrium with the flow and sediment transport for that particular condition. These phase diagrams are used for two main purposes: i) for prediction of bed states in a known flow and sediment transport condition, and, ii) as a tool for the reconstruction of paleoenvironments from a known bed state or sedimentary structure. Despite the great utility of such diagrams, they are very difficult to construct, making them either incomplete or very hard to interpret. This complexity lies in the number of variables needed to quantify the system.
Bedforms vs. flow.
Typical unidirectional bedforms represent a specific flow velocity, assuming typical sediments (sands and silts) and water depths, and a chart such as below can be used for interpreting depositional environments, with increasing water velocity going down the chart.
This chart is for general use, because changes in grain size and flow depth can change the bedform present and skip bedforms in certain scenarios. Bidirectional environments (e.g. tidal flats) produce similar bedforms, but the reworking the sediments and opposite directions of flow complicates the structures.
This bed form sequence can also be illustrated diagrammatically:
Types of Bedforms.
Lower Plane Bed.
"Lower plane bed" refers to the flat configuration the bed of a river that is produced in via low rates of sediment transport.
Upper Plane Bed.
"Upper plane bed" features are flat and characterized by a unidirectional flow with high rates of sediment transport as both bed load and suspended load. Upper plane bed conditions can produce parting current lineations, which are typically subtle streaks on the bed surface due to the high energy flow.


Domengine Formation

The Domengine Formation is a geologic formation in California. It preserves fossils dating back to the Paleogene period.


Murray Formation

The Murray Formation is the name given to a distinctive mudstone geologic formation studied by the Mars Science Laboratory (MSL) Curiosity at the Gale Crater, Mars.
Stratigraphy.
The formation is more than thick and is part of the Mount Sharp Group which interfingers with units of the Bradbury Group. The formation is composed mostly of basaltic minerals plus clays, though an intermediate horizon contains tridymite, cristobalite, quartz and opal.
The Murray formation has five named subunits, i.e. Pahrump Hills Member, Hartmann's Valley Member, Karasburg Member, Sutton Island Member, Vera Rubin Ridge Member. It unconformably underlies the Stimson formation.


Sequence (geology)

In geology, a sequence is a stratigraphic unit which is bounded by an unconformity at the top and at the bottom.
Definition.
In a more rigorous and general way a sequence is defined as a
"relatively conformable [...], genetically related succession of strata bounded by unconformities or their correlative surfaces"
Special cases and related concepts.
Special cases of sequences include type 1 sequences and type 2 sequences. A related concept are parasequences. Contrary to their name they are not smaller sequences.


Tintina (rock)

Tintina is a rock on the surface of Aeolis Palus, between Peace Vallis and Aeolis Mons (Mount Sharp), in Gale crater on the planet Mars. The approximate site coordinates are: .
The rock was encountered by the "Curiosity" rover on the way from Bradbury Landing to Glenelg Intrigue in January 2013. The rover ran over the rock and broke it. revealing white surface area in the rock. This was the brightest material yet seen by MastCam up to that time.
When the broken white area was analyzed with the rover's MastCam, strong signals of mineral hydration, as indicated by a ratio of near infrared reflectance intensities, were found. According to mission scientists, the mineral hydration signals were consistent with hydrated calcium sulfate, and a watery past on Mars.


Thin section

In optical mineralogy and petrography, a thin section (or petrographic thin section) is a laboratory preparation of a rock, mineral, soil, pottery, bones, or even metal sample for use with a polarizing petrographic microscope, electron microscope and electron microprobe. A thin sliver of rock is cut from the sample with a diamond saw and ground optically flat. It is then mounted on a glass slide and then ground smooth using progressively finer abrasive grit until the sample is only 30 μm thick. The method uses the Michel-Lévy interference colour chart. Typically quartz is used as the gauge to determine thickness as it is one of the most abundant minerals.
When placed between two polarizing filters set at right angles to each other, the optical properties of the minerals in the thin section alter the colour and intensity of the light as seen by the viewer. As different minerals have different optical properties, most rock forming minerals can be easily identified. Plagioclase for example can be seen in the photo on the right as a clear mineral with multiple parallel twinning planes. The large blue-green minerals are clinopyroxene with some exsolution of orthopyroxene.
Thin sections are prepared in order to investigate the optical properties of the minerals in the rock. This work is a part of petrology and helps to reveal the origin and evolution of the parent rock.
A photograph of a rock in thin section is often referred to as a photomicrograph.
Quartz in thin section.
Description.
In thin section, when viewed in plane polarized light (PPL), quartz is colorless with low relief and no cleavage. Its habit is either fairly equant or anhedral if it infills around other minerals as a cement. Under cross polarized light (XPL) quartz displays low interference colors and is usually the defining mineral used to determine if the thin section is at standardized thickness of 30 microns as quartz will only display up to a very pale yellow interference color and no further at that thickness, and it is very common in most rocks so it will likely be available to judge the thickness.
Determining provenance.
In thin section, quartz grain provenance in a sedimentary rock can be estimated. In crossed polarized light, the quartz grain can go extinct all at once, called monocrystalline quartz, or in waves, called polycrystalline quartz. The extinction in waves is called undulose extinction and indicates dislocation walls in mineral grains. Dislocation walls are where dislocations, intracrystalline deformation via movement of a dislocation front within a plane, organize themselves into planes of sufficient quantity. They change the crystallographic orientation across the walls, so for example in quartz, the two sides of the wall will have slightly different extinction angles and thus result in undulose extinction. Since undulose extinction requires dislocation walls to have developed, and these occur more easily at higher pressures and temperatures, quartz grains with undulose extinction indicate metamorphic rock provenance for that grain. Those grains that are monocrystalline quartz are more likely to have been formed by igneous processes. Differing sources suggest the extent to which this proxy for provenance can be used. Some note the trend for immature sandstones to have less polycrystalline quartz grains compared to mature sandstones, which have grains that have passed through many sedimentary cycles. Quartz grains derived from previous sedimentary sources are determined by looking for authigenic, or grown in place, overgrowths of silica cement over the grain.
Other distinguishing features.
The above descriptions of quartz in thin section is usually enough to identify it. Minerals with similar appearance may include plagioclase, although it can be distinguished by the distinctive twinning in crossed polarized light and cleavage in plane polarized light, and cordierite, although it can be distinguished by twinning or inclusions in the grain. However, for certainty, other distinguishing features of quartz include the fact that it is uniaxial, it has a positive optic sign, length-slow sign of elongation, and zero degree extinction angle.
Ultra-thin sections.
Fine-grained rocks, particularly those containing minerals of high birefringence, such as calcite, are sometimes prepared as ultra-thin sections. An ordinary 30 μm thin section is prepared as described above but the slice of rock is attached to the glass slide using a soluble cement such as Canada balsam (soluble in ethanol) to allow both sides to be worked on. The section is then polished on both sides using a fine diamond paste until it has a thickness in the range of 2-12 μm. This technique has been used to study the microstructure of fine-grained carbonates such as the Lochseitenkalk mylonite in which the matrix grains are less than 5 μm in size. This method is also sometimes used in the preparation of mineral and rock specimens for transmission electron microscopy and allows greater accuracy in comparing features using both optical and electron imaging.


Gallatin Formation

The Gallatin Formation is a geologic formation in Wyoming and Montana. It preserves fossils dating back to the Cambrian period.


Enipeus Vallis

Enipeus Vallis is a valley in the northern hemisphere of the planet Mars. It is centered at lat. 37°N, long. 267°E in the Arcadia quadrangle (MC-3) between the large volcano Alba Mons and the Tempe Terra plateau. The valley follows a gently sinuous, north-south path for a distance of about 357 km (222 mi). It is likely an ancient watercourse that formed during the early Hesperian (or late Noachian) period, around 3.7 billion years ago.
The valley is named after a river in Thessaly, Greece. Enipeus is also the name of a river god in classical mythology. The International Astronomical Union (IAU) formally adopted the name Enipeus Vallis in 1991. "Vallis" is the Latin word for valley.
General description.
Enipeus Vallis is mapped as a valley network. Valley networks are branching systems of valleys on Mars that superficially resemble terrestrial river drainage basins. They are abundant in the equatorial and southern highlands of the planet but less common in the northern hemisphere. Most valley networks are thought to have formed by flowing water, although the primary source of the water (melting ice, rainfall, springs) is still debated.
Enipeus Vallis is a single trunk valley, with no large tributaries. The valley is widest (about ) at its southernmost reach near Lat. 33.6°N and rapidly tapers northward, maintaining a regular width of throughout most of its course. Above lat. 39.7°N the valley opens up, and drainage features become poorly integrated and ill-defined. North of this area, a somewhat subdued valley segment continues to the northwest from 40.5°N to about 42.5°N (northwest of the crater Lowbury) where it is locally buried by impact crater ejecta and young (Amazonian-aged) plains material. This northern valley segment gradually loses its identity amid the narrow grabens of Tantalus Fossae.
The elevation of the valley floor ranges from above datum (Mars "sea" level) in the south to or less in the north, where the northern segment of the valley begins to lose its definition. In cross-sectional profile, the valley is U-shaped to rectangular, with depths ranging from . In the south, Enipeus Vallis has levee-like ridges along its edges that are up to high. The levees are locally breached by lava flows from the surrounding plains.
In places, inner channels are visible along the valley floor. At around 36°N, the channels form an anastomosing (braided) pattern. Near the middle section of the southern valley segment, the valley divides into several branches, which then rejoin to form diamond-shaped islands. Faint longitudinal striations and streamlined erosional bedforms are common all along the floor of the valley. (See Photo Gallery.)
In fluvial geomorphology, a distinction is made between the terms stream valley and stream channel. Stream valleys are wide, elongate depressions. The stream itself flows within the confines of a channel in the center of the valley. A stream valley usually contains many channels. Channels are always much narrower and shallower than the valley that contains them, and water in the stream channel never comes close to filling the entire valley.
The distinction is important when discussing features of probable fluvial origin on Mars. Although Enipeus Vallis is described here as a valley, it has many features typical of a channel, including fluvial bedforms, streamlined features, a U-shaped profile, and levee deposits, which are always associated with channels not valleys. Except for its small width and general sinuosity, Enipeus Vallis has characteristics resembling the immense Martian outflow channels, which are true channels formed by the catastrophic release of large volumes of water. Fluvial landforms like Enipeus Vallis that show characteristics of both valley networks and outflow channels are relatively common on Mars (Ma'adim Vallis, for example). and indicate that fluvial erosion on Mars has a distinctive genesis and evolution compared to Earth.
Regional geology.
Enipeus Vallis is located at the western edge of the Tempe Terra plateau in the Tempe-Mareotis region. The region lies on a broad topographic shelf bounded by the higher elevations of Alba Mons to the west and Tempe Terra to the east. The region slopes gently to the north with a gradient of 0.3° or less. The area is characterized by abundant lava flows, low volcanic shields, and small domes that are part of the Tempe Volcanic Province, a northeastern extension of the Tharsis Montes chain of volcanoes. Although spatially related to the large Tharsis volcanoes, volcanism in the Tempe Volcanic Province has a different eruptive style and has been likened to the basaltic plains volcanism seen in Idaho’s Snake River Plain. This category of volcanic activity is intermediate between flood (plateau) basalts and Hawaiian volcanism.
The region is transected by numerous northeast-trending grabens that form parts of the Tempe, Mareotis, and Tantalus Fossae; these are fracture systems of varying ages that are oriented radially from the Tharsis bulge. The region west of Enipeus Vallis is characterized by Hesperian-aged volcanic flows from Alba Mons. The area to the east consists of fractured and terraced highland plateaus of Noachian age. At the end of the Noachian period, these highland materials underwent an episode of fluvial erosion and resurfacing. Enipeus Vallis probably formed during this fluvial episode.


Scotch Grove Formation

The Scotch Grove Formation is a geologic formation in Iowa. It preserves fossils dating back to the Silurian period.


Atoka Formation

Named after Atoka County, Oklahoma, the Atoka Formation is a geologic formation in central and western Arkansas, eastern Oklahoma, central and western Texas, and eastern New Mexico. It is the surface rock of the Boston Mountains and dominates exposures in the Frontal Ouachita Mountains of the Arkansas River Valley.
Sedimentology.
The Atoka Formation is a sequence of marine sandstones, siltstones, and shales, and may be as thick at 25,000 feet in the Ouachita Mountains. The formation is conformable with the Bloyd Shale in the Boston Mountains and the Johns Valley Formation in the Ouachita Mountains.


Bend Group

The Bend Group is a geologic group in Texas. It preserves fossils dating back to the Carboniferous period.


Anguille Group

The Anguille Group is a geologic group in Newfoundland and Labrador. It preserves fossils dating back to the Carboniferous period.


Ceratophyton

Ceratophyton is a genus of Cambrian acritarch, around 100–200 µm in length, produced by a eukaryotic (metazoan?) organism.
Affinity.
"Ceratophyton" has been interpreted as an originally chitinous component of a metazoan. An arthropod relationship has been proposed, although on a more conservative view it is difficult to provide confident classification beyond saying that they are fragments of a eukaryote. Particular species, however, show promising similarity to the sclerites of modern priapulid worms.
Species.
"C. vernicosum".
This species, the type, comprises a single unornamented cone.
This species occurs in platform settings in western Russia in the Lontova and Lyukati horizons, first occurring in the local base of the 'Cambrian'.<ref name="doi10.1017/S0016756800009900"></ref> In Poland it occurs from the base of the Cambrian ("Platysolenites" zone) to the "Schmidtiellus" zone.
It has been reported from the middle Cambrian of Belgium, although these specimens are short on diagnostic features.
It also occurs below the "T. pedum" zone, indicating the presence of the producer in the Ediacaran period.<ref name="doi10.1016/j.palwor.2006.10.014"></ref>
"C. circufuntum".
This species is represented by single cones that have rings around their bases.
"C. duplicum".
This taxon has a double wall, resembling a pair of stacked cones; it may represent a taphomorph of "C. vernicosum".
"C. dumufuntum".
This single cone has short conical spines, which occur on its basal region.
This species is known from the mid-to-late Atdabanian siltstones of the Ouldburra formation of Australia.
"C. spinuconum".
This taxon again comprises a single cone; it has spines and processes along both margins.
Differences from other taxa.
"Ceratophyton" differs from "Veryhachium" in having a basal opening.


Christopher Anne Suczek

Christopher Anne Suczek (September 6, 1942 – April 10, 2014) was a sedimentary geologist who specialized in sedimentary petrology and plate tectonics. She received her bachelor's degree from the University of California, Berkeley in 1972 and later went on to get her PhD in Geology from Stanford University in 1977. She is best known for her contribution in determining the correlation between sedimentary deposits and plate tectonics. By the 1980s the exploration of hydrocarbons and a continuation of tectonic studies in the Pacific Northwest area of the United States led to a need of increased knowledge of the Tertiary sedimentary basins and Suczek's mapping of the area.
Professor.
In her professional career, Suczek was a professor emeritus at Western Washington University for nearly 40 years. Some of the courses she taught were stratigraphy, sedimentation, physical and historical geography. Suczek also held a seat on the Auditing Committee for the Paleontological Society. Suczek was a known mentor to many of her students, especially her female students. She was known for always speaking her mind and leading the way for women in a field that is still underrepresented by females. Along with being a successful professor and sedimentary geologist Suczek also had a son and a granddaughter. Suczek died on April 10, 2014 at age 71, at her home in Bellingham, after being ill for over a year with pancreatic cancer.
Scientific work.
Suczek's first major contribution to the scientific world of plate tectonics came in the form of her dissertation that she composed while completing her Ph.D. at Stanford University (1977). In her dissertation, she studied the Upper Cambrian Harmony Formation in Northern Nevada, in an intent to prove if any of the plate tectonic models could be accurate.
Throughout her study, Suczek develops two models in an attempt to describe plate tectonic behaviour in connection with the Upper Cambrian Harmony Formation. Out of these two models Suczek found evidence to believe that the passive continental margin model seemed to be most likely as it lasted until the end of Cambrian time and a time constraint of 650 million years of spreading event are met. A lack of volcanic ash can also be accounted for with the passive continental margin model. Suczek does note that some problems remain even with this model such as the nature of crust under the miogeocline and the continued finding of almost pure quartzite in the eugeocline.
Suczek herself notes that further study to find comparisons between the harmony foundation, Northern Sierra, Klamath Mountains, Shoofly Moffett Creek and Antelope Mountain could lead to more evidence supporting this model.
Publication.
In 1983, Suczek published a journal article on Disaggregation of quartzites in the "Journal of Sedimentary Petrology". She explained that the common method of analyzing grain sizes was through sieving and that this method was very time-consuming and the results are not accurate (apart from the median and graphic means). Instead, she proposed and described a method where the cement is dissolved by hydrofluoric acid to isolate the quartzites. She built this off of a model developed by Pessagno and Newport. Her method is more efficient as the immersion is only 30 minutes long.
Suczek worked with Raymond V. Ingersoll (from the Department of Earth and Space Science at the University of California) in 1985 to publish their work in the Journal of Sedimentary Research on Petrology and provenance of Cenozoic sand from the Indus Cone and the Arabian Basin. The article describes the uplifted gneissic, sedimentary and metasedimentary terrane of the western Himalayas that was produced by the closing of the ocean between India and Asia. They were trying to test if the sand from the Arabian Basin was derived from the Himalayas to find out what petrographic characteristics were present. They then compared samples with the sand from the Bengal and Nicobar Fans. This comparison would help explain tectonic movements in the region from convergence and collision of India and Asia causing the Himalayan orogenic belt. In order to do this, they used samples from three of the Deep Sea Drilling Project's holes, counting the layers to find the Cenozoic sand.
Using their findings, they compared results with other petrological data. Part of the discussion includes references to Suczek's previous work with others where they were attempting to find data to differentiate sand weathered off orogenic belts created by continental collision. The new data they found strongly suggests that parts of the samples show characteristics of the sands derived from collision zones as opposed to Atlantic-type margins. There is a reference to papers she collaborated on in 1979 where triangular diagrams were used to differentiate sands of different tectonic provenance. However, in the paper 6 years later they decided to use the QpLvmLsm plot instead of as it visibly illustrates their sands as part of the group of sands derived from continental collisions and distinct from other groups.
Finally, the conclusion explains that two out of the three Deep Sea Drilling Project samples were derived from the Himalayas and the third sample was a combination of Himalayan and Arabian sources. Also, the Arabian Sea samples matched the sand samples from the Bengal and Nicobar Fans.
Paleogeographic evolution paper.
In 1986 and then revised in 1987, Suczek along with Paul Heller and Rowland Tabor published their paper on paleogeographic evolution of the United States Pacific Northwest during Paleogene Time in the "Canadian Journal of Earth Sciences". This work was to brief the paleogeographic history of the area during Paleogene times. To do this Suczek, Heller and Tabor looked at igneous, sedimentary and deformational histories which then allowed them to create a series of paleogeographic maps. This study resulted in the description of three main phases of Paleogene basin evolution.
The first phase consisted of formation due to the collision of oceanic islands which occurred along the continental margin. Sediments found in this phase were created from orogenic highlands. The second phase had formed within a broad forearc region and was marked by rapid subsidence of individual basins. Due to extension, maybe in conjunction with transcurrent faulting, nonmarine basins had formed. Found in both the marine and nonmarine basins were rapid sedimentation that was made up of sandstone from cretaceous plutonic sources far to the east. The third and final phase was marked by the growing Cascade volcanic arc which had begun in early Oligocene times. This growth in the volcanic arc caused changes to the basin makeup. The Cascade Range would divert streams carrying eastern derived material, reduce sedimentation rates in the coastal basins and provide a local source of volcanic detritus.