Christian Koeberl

Christian Köberl (born February 18, 1959 in Vienna) is a professor of impact research and planetary geology at the University of Vienna, Austria. From June 2010 to May 2020 he was director general of the Natural History Museum in Vienna. He is best known for his research on meteorite impact craters.
Biography and career.
Born in Vienna, Austria, in 1959, Köberl attended a technical high school specializing in chemistry, and from 1978 studied chemistry and physics at the Technical University of Vienna, as well as astronomy at the University of Vienna. In 1983, he completed his PhD studies at the University of Graz, Austria, with a dissertation in cosmochemistry. In 1985 he joined the faculty of the newly founded Institute of Geochemistry at the University of Vienna, becoming an assistant professor. In 1988, he joined the Lunar and Planetary Institute (Houston, TX, USA) and the NASA Johnson Space Center for half a year as a Fulbright Scholar. This was followed by several more research appointments at these institutions. In 1990, he obtained the "Habilitation" in Geo- and Cosmochemistry at the University of Vienna and was awarded tenure as associate professor.
From 1992-1995, Koeberl spent several months of each year at the isotope geochemistry laboratories of the Department of Terrestrial Magnetism at the Carnegie Institution in Washington, DC, USA, to work on osmium isotope geochemistry. In 1993, he was a visiting professor at the University of the Witwatersrand, Johannesburg, South Africa, and, in 1994, a visiting professor at the Department of Earth Sciences, Dartmouth College, New Hampshire, USA, where he remained an adjunct professor from 1994 to 2000.
In 2004, Koeberl was elected corresponding member, and in 2006 full member of the Austrian Academy of Sciences. In 2006, an asteroid was named after Köberl. In 2007, he received the Barringer Medal of the Meteoritical Society, its highest award for research related to impact cratering studies. From 2007 to 2010, Köberl served as Visiting Research Professor at the Department of Earth Sciences and the Planetary and Space Science Research Institute, Open University, Milton Keynes, United Kingdom. From 2008 until 2010, he was head of the Department of Lithospheric Research, one of the earth science departments at the University of Vienna.
From March 2009,Koeberl was appointed full professor of impact research and planetary geology at the University of Vienna. In December 2009, he was appointed director general of Vienna's Natural History Museum, a post that he took up in June 2010. In addition to remaining on the faculty of the University of Vienna, he is also a member of the board of the Austrian Science Fund, and is editor of the "Bulletin of the Geological Society of America" and co-editor of the journals "Geochimica et Cosmochimica Acta" and "Meteoritics & Planetary Science".
Research.
Köberl's research activities center around two main themes: the investigation of impact cratering related processes and rocks through detailed and multidisciplinary investigations (mainly using geochemistry, petrography, and mineralogy, but also field geology and geophysics), as well as the development and testing of new methods that can be applied for such studies. He has made contributions to our knowledge of a large number of impact structures, particularly in terms of impact geochemistry, and has in some cases contributed to the discovery of previously unknown impact craters.
His other major research topic involves the determination of extraterrestrial components in impact-related rocks. In addition, Köberl has spent decades in studying tektites, and his work was important in reaching the conclusion that these are a rare form of terrestrial glasses that form in the earliest phases of crater formation. He has been the principal investigator of several International Continental Scientific Drilling Program (ICDP) drilling projects: at the Bosumtwi impact crater in Ghana in 2004, the Chesapeake Bay crater drilling project in the USA in 2005/6, the El'gygytgyn crater project in the Russian Arctic in 2009, and the planned Songliao Basin drilling project in China.
Additional research interests include investigations of terrestrial mass extinction horizons (including the late Eocene, K-Pg, Tr-J, and P-Tr strata), of meteorites and lunar rocks, Antarctic meteorite field studies, snowball earth, and several other geochemistry-related issues. He participated in or led numerous field expeditions, including Antarctica in 1986/7 and desert regions in Namibia, South Africa, Egypt, Libya, Mauritania, and Mongolia, and to numerous impact craters around the world. He participated in several documentary movies on impact related topics. From 1998 to 2003 he was chair and coordinator of the European Science Foundation "Impact" program. He is also on the science team of the Midas experiment on board the Rosetta comet probe.
Köberl has written or edited 15 books and is the author of over 450 peer-reviewed research publications. He has organized several international research conferences, including the Annual Meeting of the Meteoritical Society in 1989 in Vienna, Austria; the meeting on Catastrophic Events & Mass Extinctions: Impacts and Beyond, in 2000 in Vienna, Austria; Geological Society of America Field Forum on "Bolide Impacts on Wet Targets" in Nevada and Utah, USA; and the Geological Society of America Penrose Conference on "Hothouse, Icehouse, and Impacts: The Late Eocene Earth" at Monte Conero in Italy.
In his capacity as director general of the Natural History Museum in Vienna, Köberl is planning to increase the quality and visibility of research at the museum, to provide a larger number and greater variation of special exhibitions covering modern natural sciences, and to renovate and update the permanent exhibitions.


Pampu Facula

Pampu Facula is a bright region on the surface of Mercury, located at 57.76° S, 31.79° W. It was named by the IAU in 2019. "Pampu" is the Tamil word for snake.
Pampu Facula is centered northeast of Hesiod crater.


Lamination (geology)

In geology, lamination is a small-scale sequence of fine layers ("laminae"; singular: "lamina") that occurs in sedimentary rocks. Laminae are normally smaller and less pronounced than bedding. Lamination is often regarded as planar structures one centimetre or less in thickness, whereas bedding layers are greater than one centimetre. However, structures from several millimetres to many centimetres have been described as laminae. A single sedimentary rock can have both laminae and beds.
Description.
Lamination consists of small differences in the type of sediment that occur throughout the rock. They are caused by cyclic changes in the supply of sediment. These changes can occur in grain size, clay percentage, microfossil content, organic material content or mineral content and often result in pronounced differences in colour between the laminae. Weathering can make the differences even more clear.
Lamination can occur as parallel structures (parallel lamination) or in different sets that make an angle with each other (cross-lamination). It can occur in many different types of sedimentary rock, from coarse sandstone to fine shales, mudstones or in evaporites.
Because lamination is a small structure, it is easily destroyed by bioturbation (the activity of burrowing organisms) shortly after deposition. Lamination therefore survives better under anoxic circumstances, or when the sedimentation rate was high and the sediment was buried before bioturbation could occur.
Origin.
Lamination develops in fine grained sediment when fine grained particles settle, which can only happen in quiet water. Examples of sedimentary environments are deep marine (at the seafloor) or lacustrine (at the bottom of a lake), or mudflats, where the tide creates cyclic differences in sediment supply.
Laminae formed in glaciolacustrine environments (in glacier lakes) are a special case. They are called varves. Quaternary varves are used in stratigraphy and palaeoclimatology to reconstruct climate changes during the last few hundred thousand years.
Lamination in sandstone is often formed in a coastal environment, where wave energy causes a separation between grains of different sizes.


Nuclear magnetic resonance logging

Nuclear magnetic resonance (NMR) logging is a type of well logging that uses the NMR response of a formation to directly determine its porosity and permeability, providing a continuous record along the length of the borehole.
Background.
NMR logging exploits the large magnetic moment of hydrogen, which is abundant in rocks in the form of water. The NMR signal amplitude is proportional to the quantity of hydrogen nuclei present in a formation and can be calibrated to give a value for porosity that is free from lithology effects. Uniquely, a petrophysicist can also analyse the rate of decay of the NMR signal amplitude to obtain information on the permeability of the formation - a crucial quantity in hydrocarbon exploration.
Relationship of NMR signal to pore size.
The most important mechanism affecting NMR relaxation is grain-surface relaxation. Molecules in fluids are in constant Brownian motion, diffusing about the pore space and bouncing off the grain surfaces. Upon interaction with the grain surface, hydrogen protons can transfer some nuclear spin energy to the grain (contributing to T1 relaxation) or irreversibley dephase (contributing to T2 relaxation). Therefore the speed of relaxation most significantly depends on how often the hydrogen nuclei collide with the grain surface and this is controlled by the surface-to-volume ratio of the pore in which the nuclei are located. Collisions are less frequent in larger pores, resulting in a slower decay of the NMR signal amplitude and allowing a petrophysicist to understand the distribution of pore sizes.


Great Blue Limestone

The Great Blue Limestone is a geologic formation in Utah. It preserves fossils dating back to the Carboniferous period.


Nott Corona

Nott Corona is a corona, a geological formation in the shape of a crown, located on the planet Venus at -32.3° N and 202° E. It is located in the Isabella quadrangle. It is named after Nótt, the Scandinavian goddess of the Earth.
Geography and geology.
Nott Corona covers a circular area about 150 km in diameter.
External links.
[[Category:Surface features of Venus]]


Ilmenau Formation

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


Assise de Muse

The Assise de Muse is a geologic formation in France. It preserves fossils dating back to the Permian period.


Alzey Formation

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


Happy Creek Formation

The Happy Creek Formation is a geologic formation in Nevada, United States. It preserves fossils dating back to the Permian period.


Cally Oldershaw

Cally Oldershaw is a gemologist and science educator. She is the author of several very widely held books about gems. Oldershaw is Liaison Officer for the Geological Society of London and an examiner for the Gemmological Association of Great Britain.
Bibliography.
She also wrote the multiple parts of the Geological society of London series of booklets, "Earth in our hands", and many parts of the "Series: Closer look at..." series for children published by Copper Beech Books.


Honsel Formation

The Honsel Formation is a geologic formation in Germany. It preserves fossils dating back to the Devonian period.


Garber Sandstone

The Garber Sandstone is a geologic formation from the Permian Period in Oklahoma. It serves as an important aquifer, the Garber-Wellington Aquifer, in Logan, Oklahoma, and Cleveland counties of central Oklahoma.
The upper portion of the Garber is associated with extensive baryte mineralization associated with desert rose occurrences in the outcrop area.


Duyfor Mudstone

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


Ross Mine Formation

The Ross Mine Formation is a geologic formation in Texas. It preserves fossils dating back to the Permian period.


Tectonic burial

Tectonic Burial is the deformation of rocks caused by extreme pressure over millions of years. It often causes temperature evolution's and deep burials. Tectonic burial is usually the result of continental collisions or subduction in a region. An increase in burial depth leads to a weakened basin and basement but creates better preservation structure within the basement.
Geologic Processes.
Sedimentary Burial.
Sedimentary burial is more typical when thinking of burial processes. Sedimentary burial is the deposition of sediments on and area of interest such as a sedimentary basin, oceans, or other locations typically leading to Diagenesis.
Tectonic Burial.
Tectonic Burial specifically refers to burial of material on a area of interest as a result of tectonic processes such as a Thrust fault or other processes of crustal thickening. Tectonic burial is common in orogenic systems such as mountain belts or collisional zones. This is a critical part of the rock cycle and can lead to burial metamorphism and heating.
Evidence for tectonic burial.
Radiometric Dating.
One way of identifying a tectonic burial event is through radiometric dating. Burial events may be radiometric dated by looking at the cooling of the event and its impact on the minerals within the formation.
Metamorphism.
When rocks or sediments get buried they begin to increase in temperature and pressure as the mass above accumulates. Metamorphism occurs at temperatures greater than 200 °C and pressures greater than 300 MPa. Burial metamorphism overlaps with diagenesis with an increase in pressure and temperature. Sedimentary rocks buried at depths of a couple kilo meters will begin generating temperatures above 300 °C without differential stress.
Thermochronology.
Tectonic burial events can be distinguished by Thermochronology. During a tectonic burial event rocks increase in heat until they reach their Closure temperature . These closure temperatures are an indication of burial depth history and are used by thermochronogists in dating a tectonic burial event.
Vitrinite Reflectance.
Sediment deposition over a basin with organic material can create a primary component of coal, Vitrinite. High temperatures and pressures associated with Tectonic burial could produce vitrinite from woody organic material thus the presence of vitrinite may be a good indicator for a tectonic burial event.
Effects.
Coalification.
It has been debated that burial depth may play a role into the advancement of coalification. Early in the 19th century it was thought to be caused purely by the pressure caused by burial, in some coal fields high ranking coal was found that made some geologists think that burial pressure increased the coalification rate.
Oil.
Oil can be another product of tectonic burial. Oil is created in this fashion over a series of steps starting with the deposition of carbonate sediments followed by cracking and multiple stages of filling of oil like inclusions.
Pressure-Temperature-Time paths.
One of the largest effects that tectonic burial has is a change in the pressure-temperature time paths, this can be identified by looking for metamorphism or by using thermochronology.
Burial of greater depths have the ability to reset fission track dates.
Examples.
Tectonic burial in southern Apennines..
In the southern Apennines fold and thrust belts, indicators record timing of exhumation of sedimentary units.
Tectonic burial in the Persian Gulf..
Evidence for the timing of diagenesis and oil migration.
Tectonic burial and Coal production..
Tectonic burial and its relationship to the advancement of coalification.


Mann Formation

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


Scott Canyon Formation

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


Antler Peak Formation

The Antler Peak Formation is a geologic formation in Nevada. It preserves fossils dating back to the Permian period.


Ekaterina Lermontova

Ekaterina Vladimirovna Lermontova (11 February 1889 – 9 January 1942) was a Russian Empire and Soviet paleontologist responsible for creating the first Cambrian stratigraphy of Siberia. Species of fossil animals and algae, as well as Cambrian biostratigraphic divisions are named in her honor.
Early life and education.
Lermontova was born in St. Petersburg to a family including Mikhail Lermontov, a poet, and Iuliia Lermontova, a chemist. She was educated at the Women's Pedagogical Institute and graduated in 1910, then received a degree from the University of St. Petersburg in 1912.
Career and research.
In 1921, she was employed by the Geological Committee and the All-Union Scientific Research Institute of Geology. Lermontova's research focused on Cambrian fossils in Siberia; she was the first researcher to investigate Cambrian trilobites in the then-USSR. Her research included trilobite fossils in Kazakhstan, Siberia, the Ural Mountains, and Middle Asia. She was killed in the Siege of Leningrad during World War II.
Legacy.
Lermontova is the namesake of biostratigraphic divisions of the Cambrian and of fossil animals and algae from the Cambrian.


Briolette

A briolette is a style of gemstone cut - an elongated, faceted pear shape. It is often drilled to hang as a bead. The style was popular during the Victorian era.
The Smithsonian Institution has a diamond briolette necklace presented by Napoleon Bonaparte in 1811 to his Empress consort Marie Louise.


Eugene Thomas Allen

Eugene Thomas Allen (2 April 1864 – 17 July 1964) was an American pioneer of geochemistry who worked at the Geophysical Laboratory of the Carnegie Institution.
Allen was born to Frederick and Harriet Augusta (born Thomas) in Athol, Massachusetts. He received an AB from Amherst College 1887 and studied chemistry at Johns Hopkins University, receiving a PhD in 1892. He taught chemistry at the University of Colorado (1892-1893) and at the Missouri School of Mines (1895-1901). From 1879 he collaborated with G.F. Becker and Carl Barus at the newly founded US Geological Survey to study the chemistry of rocks. In 1906 he moved to the Geophysical Laboratory of the Carnegie Institution of Washington established in the previous year with Arthur Louis Day as director.
Allen worked on silicate minerals which included experimental synthetic approaches in petrological studies. In 1925 Allen and Day worked on geysers and hot springs of Yellowstone.
Allen married Harriet Doughty at Arlington in 1896.


Blackwater Limestone

The Blackwater Limestone is a geologic formation in Northern Ireland. It preserves fossils dating back to the Carboniferous period.


St. Charles Formation

The St. Charles Formation is a geologic formation in Idaho. It preserves fossils dating back to the Cambrian period.


Hope Gate Formation

The August Town Formation is a geologic formation in Jamaica. It preserves fossils dating back to the Neogene period.


Highstand systems tract


San Jacinto Fault Zone

The San Jacinto Fault Zone (SJFZ) is a major strike-slip fault zone that runs through San Bernardino, Riverside, San Diego, and Imperial Counties in Southern California. The SJFZ is a component of the larger San Andreas transform system and is considered to be the most seismically active fault zone in the area. Together they relieve the majority of the stress between the Pacific and North American tectonic plates.
The SJFZ itself consists of many individual fault segments, some of which have only been individualized as recently as the 1980s, but activity along the line of faults has been documented since the 1890s. One segment of the SJFZ, the Anza seismic gap, has not experienced any major activity since instrumental records have been kept. Each segment was evaluated for its seismic risk and was assigned a probability for the occurrence of a large rupture for the thirty-year period starting in 1995.
While several of the large earthquakes along the SJFZ have not resulted in significant property damage or loss of life (due to their remote location) the cities of Hemet and San Jacinto were both heavily damaged in two significant events in 1899 and 1918. The recurrence interval for a series of large earthquakes starting in 1899 (including the 5.9 1937 Terwilliger Valley earthquake) was 18, 5, 14, 5, 12, 14, and 19 years, yet there has not been a strong earthquake for years (since the 1987 Superstition Hills and Elmore Ranch sequence).
Characteristics.
The San Jacinto Fault Zone and the San Andreas Fault (SAF) accommodate up to 80% of the slip rate between the North American and Pacific plates. The extreme southern portion of the SAF has experienced two moderate events in historical times, while the SJFZ is one of California's most active fault zones and has repeatedly produced both moderate and large events. The locations of earthquakes before the 1954 Arroyo Salada earthquake are not precisely known, but the events' effects place them on the SJFZ and not on the SAF. The 1923 North San Jacinto Fault earthquake struck the Inland Empire area of southern California at a time of relatively low population, and a repeat event in modern times would result in heavy property damage and loss of life.
Segments.
A 1995 report by the Working Group on California Earthquake Probabilities identified seven individual segments of the SJFZ. The group consisted of more than three dozen seismologists, including Keiiti Aki and C. Allin Cornell, and was organized by the Southern California Earthquake Center for the USGS and the California Office of Emergency Services. The 1995 paper was the third in a series of reports that was set in motion following the 1992 Landers earthquake in southern California with the intention of updating the data and the approach for calculating the probabilities for large earthquakes along the southern San Andreas and San Jacinto Fault zones. Both these fault zones were grouped together as having adequate paleoseismic data to assign conditional probabilities for future damaging earthquakes.
The original Working Group in 1988 had identified five segments of the fault zone. From north to south, the segments were labeled the San Bernardino Valley, San Jacinto Valley, Anza, Borrego Mountain, and Superstition Hills. The 1995 group then added the Coyote Creek and Superstition Mountain segments, defined the Anza segment to include the Clark and Casa Loma faults, and updated the slip rates for each segment. The three northern sections (San Bernardino, San Jacinto, and Anza) were assigned 12 mm per year of slip and the four remaining sections were given 4 mm of slip, and error rates were half the total estimated slip for each segment (±6 mm and ±2 mm respectively) with the exception of the Anza segment which had slightly exaggerated rates of +7 mm and −5 mm.
Thirty year probabilities for segment-rupturing earthquakes were estimated using three separate models then a preferred weighted result was presented for each segment. While the San Bernardino (37%) and San Jacinto (43%) segments both saw large increases since the 1988 report, due in part to increased estimates for slip rates and decreased estimates for inherent displacement, the Anza segment (17%) was determined to have a decreased probability, based on an increased segment length. The Coyote Creek (18%), Superstition Mountain (9%), and Superstition Hills (2%) segments received first time estimates (none were assigned in 1988) and the Borrego Mountain segment received a more specific value of 6%.
San Bernardino Valley.
The northernmost primary strand of the SJFZ is the Claremont strand (though subsidiary parallel strands exist). It spans a total of , from its northern endpoint in Cajon Pass to its southern endpoint in the San Jacinto Valley. Within the San Bernardino Valley itself, the SJFZ approaches or intersects the right-lateral strike-slip San Andreas Fault to the north, the oblique normal Crafton Hills Fault Zone to the east, and the Cucamonga Thrust to the west. A series of moderate earthquakes affected this area in the 1890s, though it is uncertain how many of these occurred specifically on the SJFZ. The Claremont strand has not had a major earthquake in the instrumental period, but paleoseismology indicates that its last surface rupturing event occurred in the early 19th century, and that comparable earthquakes occur on average of every 160 to 220 years.
San Jacinto Valley.
The San Jacinto Valley is a 25 km long, ~4 km wide valley that was formed by extension in a region of overlap between two major parallel strands of the SJFZ. The valley is bounded by the Claremont strand to the northwest (see above) and the 25 km long Casa Loma strand to the southeast. The Clark strand, which is separated from the Casa Loma by a small compressional step in the city of Hemet, continues southeastward out of the valley. This area was heavily damaged by the historic earthquakes of 1899 and 1918. The 1899 event is thought to have occurred within the valley, likely on the Casa Loma strand, while the 1918 event has been identified on the Clark strand between Hemet and Anza.
Anza.
While the 1988 Working Group included the Clark, Coyote Creek, and Buck Ridge faults, the 1995 Working Group limited the segment to just the Clark fault. A paleoseismic investigation on this segment at Hog Lake indicated three historical surface-rupturing events occurred around 1210, 1530, and 1750 with an average recurrence period for a magnitude 7.0–7.5 earthquake of 250 years.
Coyote Creek.
With a recurrence period of 175 (+158 / -95) years, no surface-rupturing event has occurred on this segment since 1892.
Borrego Mountain.
The extent of this segment is based on the surface rupture of the 1968 Borrego Mountain earthquake and shares a recurrence interval of 175 years.
Superstition Hills.
The 1988 Working Group defined the segment as two parallel strands, the Superstition Hills and Superstition Mountain faults, though no slip rate or recurrence interval was known. On November 23, 1987 the Working Group determined that the available information was still not adequate to assign 30-year probabilities. On November 24, 1987 the fault ruptured, along with an unknown fault (later named the Elmore Ranch fault). Kenneth W. Hudnut and Kerry Sieh examined the surface rupture (along with a trench investigation) in 1989 and estimated the slip rate for the prior 330 years to be 2 – 6 mm/yr (±1 mm). The Working Group used these new figures to assign a slip rate of 4 ±2 mm/yr with an average recurrence interval of 250 (+400 / -133) years for the segment.
Superstition Mountains.
Three surface-faulting events were found to have occurred along this newly added segment. A trench investigation by Larry Gurrola and Thomas Rockwell near the north shore of ancient Lake Cahuilla dated the events to 885–1440. The slip rate for the Borrego mountain segment (4 ± 2mm/yr) was extrapolated for use along the segment and a recurrence interval of 340 years was established.
Anza seismic gap.
With at least six and as many as ten large events since 1890, the right-lateral strike-slip SJFZ is southern California's most restless fault, with the exception of several sections which have seen less frequent activity. In a 1975 study, one of these (a stretch) was labeled the "Anza to Coyote Mountain slip gap", and was further refined in a 1984 paper by seismologists Christopher Sanders and Hiroo Kanamori to include only a smaller section near the town of Anza. By studying several moderate events (and their aftershocks) that occurred in 1967 (4.7L), 1975 (4.8L), and 1980 (5.5L), Sanders and Kanamori determined the seismogenic but locked nature of the gap. Were the entire fault segment to rupture in a single event, this newly modified length limited the potential of the segment to generate a magnitude 6.5 earthquake, similar in size to previous events along the SJFZ. However, if the slip were to extend out of the Anza area, the earthquake could be up to, but not larger than 7.0 in magnitude.
Link to San Andreas Fault.
At least six large ruptures of the San Jacinto Fault Zone are known to have followed the 1857 Fort Tejon earthquake that ruptured the central segment of the San Andreas Fault. These events began with the 1899 San Jacinto earthquake and occurred at intermittent intervals culminating with the 1987 Superstition Hills and Elmore Ranch events. The 1857 rupture spanned a total of and terminated on the southeast end near the point where the San Jacinto Fault Zone branches away from the San Andreas Fault Zone at the Cajon Pass. In a paper published in the journal "Science", Christopher Sanders plotted the earthquakes of the SJFZ by time and location and found that a uniform pattern became apparent. Moving southeastward from the Cajon Pass, the large SJFZ events appear on a line with a slope of 1.7 km per year and Sanders hypothesized that the 1857 earthquake introduced a strain pulse that migrated southeast and triggered large earthquakes as it traversed the SJFZ at that rate.
Earthquakes.
Uncertainty surrounds the details of this earthquake but recent studies suggest that a joint rupture of both the SAF and the San Jacinto Fault Zone to the southeast more closely match the damage pattern recorded about this event.
On December 25, with a maximum intensity of MM IX, this magnitude 6.6 earthquake destroyed San Jacinto and Hemet and six were killed by adobe walls that collapsed at Saboba (just east of San Jacinto). A fissure, which may have been surface rupture of the San Jacinto Fault, ran under a house that was severely damaged near Hemet. The effects of the early morning earthquake were severe. Not all the buildings in San Jacinto were completely destroyed by the thirty seconds of shaking, but most of the brick buildings' second floors were heavily damaged. ()
On April 9, a magnitude 6.4 ML earthquake with a maximum perceived intensity of MM VII hit the extreme eastern San Diego County area and created a surface break along the Coyote Creek Fault. California State Route 78 was damaged with cracks near Ocotillo Wells and large boulders blocked the Montezuma-Borrego Springs Highway. Other rockslides occurred at Palm Canyon and Split Mountain in Anza-Borrego Desert State Park. One house was split apart in Ocotillo Wells with one bedroom becoming detached from the rest of the home. The mainshock was felt in Arizona and Nevada and the largest aftershock damaged a theater's walls in Calexico near the Mexico–United States border.
According to a report in the "Los Angeles Times", this was the strongest earthquake to affect southern California since the Tehachapi earthquake fifteen years earlier. Taller buildings swayed in both Los Angeles and San Diego and power outages affected numerous areas, primarily in the cities of Imperial Valley. Power failures along with disruption to telephone service caused problems in the Hemet Valley area, and smaller power outages in Los Angeles and Orange Counties also occurred. A brick wall collapsed at a laundromat in Westmorland (in the El Centro Metropolitan Area) but no one was injured, and in the seaside neighborhoods of San Diego county several hundred windows were broken. Charles Richter, a Caltech seismologist, stated that the earthquake was centered near Ocotillo Wells about southeast of Los Angeles. The mainshock occurred at 6:28 pm and aftershocks continued through the evening, but were tapering off by 10 pm. ()
Two earthquakes in late November caused property damage totaling three million in Imperial County. The two events were separated by eleven hours and were located in the western Imperial Valley on the Superstition Hills Fault and a previously unknown fault. Damage in Westmoreland, Imperial, and El Centro consisted of collapsed chimneys, broken windows, and damaged highways. The Worthington Road bridge, at the New River, failed due to liquefaction and at the Desert Test Range Control Center, water tanks toppled into the building and other equipment crashed through a window. Activities were suspended there for several days due to the damage. The Southern California Irrigation District estimated damage to be $600,000 – $750,000. The initial shock produced a small amount of deformation in the canal's liner while the second main shock caused considerable damage to thousands of feet of canal lining in the northwest section of the valley.
Several foreshocks preceded the main shocks and a series of aftershocks included two in the range of magnitude five. On the Mexican side of the border, 50 injuries and two deaths were reported, and 44 were treated for their injuries in California. According to the spokesperson for the state of Baja California, a motor vehicle accident east of Mexicali that claimed the lives of a mother and her four-year-old son was blamed on the earthquake. Thomas H. Heaton, a USGS seismologist, stated that the faults in the area are difficult to track down because of the sediment deposited in the valley, which had been an intermittent drainage basin of the Colorado River.
The Superstition Hills fault (SHF) lies between the Coyote Creek fault that ruptured during the 1968 event and the Imperial Fault that ruptured during the 1940 El Centro earthquake and the 1979 Imperial Valley earthquake. To the northeast are several cross faults that trend northeast. One of these faults ruptured during a large aftershock of the 1979 event and another slipped as the smaller of the two shocks during the November 1987 sequence. The first shock (on what became known as the Elmore Ranch fault) measured 6.2 Ms and the shock 11.4 hours later on the SHF measured 6.6 Ms. ( & )
References.
Notes
Sources


Emily H. Vokes

Emily Hoskins Vokes (born May 21, 1930) is an American malacologist, palaeontologist, and former university professor. She is an authority on the Muricidae, a large and diverse family of predatory sea snails, or marine gastropod mollusks. Vokes worked both on her own and with her husband, geologist Harold Ernest Vokes.
Education and personal life.
Emily Hoskins was born in Monroe, Louisiana, but the family moved to New Orleans when she was eight. Vokes attended Newcomb College, then the women's undergraduate college of Tulane University, but dropped out, uncertain of her future career. She went to work for the Biophysics Laboratory and found her way to the Geology Department, where she became interested in geomorphology and later paleontology. In 1955 she re-enrolled as an undergraduate, but because Newcomb College did not then offer geology degrees to its women students, Vokes switched to Tulane. She completed her B.S. degree in geology in 1960, while working part-time as a curator of fossils. Following this she obtained both her M.S. (1962) and Ph.D. (1967) degrees from Tulane.
In 1959, Vokes married geologist Harold Ernest Vokes (1908–1998), whom she had met in 1956 when he came to Tulane to run the Geology Department. She often collaborated with him on scientific research. She published 147 articles and books alongside the 144 published under his name.
Career.
Vokes began her academic career at Tulane University in 1969 as an instructor for University College, where she worked until 1973. That year, she became an associate professor at Newcomb College. She was promoted to full professor in 1981, and later served as chair of the Geology Department and as dean of Newcomb College. She retired in 1996 and became an emerita professor. She held the post of curator for the Geology Department's collections until 1974.
Vokes and her husband helped to start a summer field-work camp in Mexico, and for over a decade they traveled annually to the Yucatan Peninsula to study molluscs, resulting in their book "Distribution of Shallow-Water Marine Mollusca, Yucatan Peninsula, Mexico" (1983).
In 1968 Vokes collected fossils in Central America, especially Costa Rica and Panama. In 1971, she spent a sabbatical collecting fossils in South America (Ecuador, Argentina, Chile, Peru) and teaching at Brazil's University of Rio Grande do Sul. In 1971, Vokes published a large study of the genus "Murex", entitled "Catalogue of the Genus "Murex" Linné (Mollusca:Gastropoda)". At the time of publication, some 2500 species had been named in the Linnaean genus "Murex", and Vokes attempted to reassign each species to its correct genus.
Between 1976 and 1986, Vokes spent a good deal of time surveying fossils in the Dominican Republic. Some of this work was part of a larger project coordinated with other researchers that aimed to identify the origins of various species found in the rock formations of the Dominican Republic. This research resulted in another of her major works, "Neogene paleontology in the Northern Dominican Republic 18: The superfamily Volutacea (in part) (Mollusca:Gastropoda)", a 1998 study of the superfamily Volutacea found in the Dominican Republic. It focused on a particular group of taxa that tend to be characterized by folding of the axial part of the shell. She was an editor of the Tulane Geology Department's journal, "Tulane Studies in Geology and Paleontology".
Vokes and her husband were the core of the paleontological research program at Tulane University, and their fossil collections were extensive. These collections included research findings from excursions to the southeastern United States, Mexico, the Dominican Republic, South America, and Europe. Vokes and her husband collected from 1546 localities, their specimens filling over 72 square yards of cabinet space. A large number of their specimens have been transferred to the Smithsonian, the University of Florida, and the Paleontological Research Institution.
Later years.
In retirement, Vokes moved to Ponchatoula, Louisiana, where she opened an antique shop.
In 2010, Vokes took part in a Tulane-sponsored trip to South Africa, where the group participated in a tree-planting program in Soweto.
Awards and legacy.
Tulane created the Emily Vokes Faculty Service Award to recognize lifetime service to the School of Professional Advancement. The award honors Vokes's service to continuing education at Tulane, including pioneering Saturday classes. In 2014, it also established the title Vokes Geology Professor, awarded in honor of both Emily and Harold Vokes.
The Drs. Emily H. and Harold E. Vokes Grants-in-Aid for Invertebrate Paleontology Collection-Based Research are given to advanced undergraduate students from anywhere in the United States who wish to use the collections at the Florida Museum of Natural History for paleobiological research.
The fossil muricid gastropod "Argenthina emilyae" was named in her honor.


Geology of Charon

The geology of Charon are the characteristics of the surface, crust, and interior of Pluto's moon Charon. Charon's diameter is —just over half that of Pluto. Charon is sufficiently massive to have collapsed into a spheroid under its own gravity.
History.
Mutual eclipses of Pluto and Charon in the 1980s allowed astronomers to take spectra of Pluto and then the combined spectrum of the pair. By subtracting Pluto's spectrum from the total, astronomers were able to spectroscopically determine the surface composition of Charon. The northern regions of Charon are composed partially of hydrocarbons and tholins, whereas the lower latitudes are more diverse in composition.
Researchers from NASA's Ames Research Center in 2017 confirmed that icy plate tectonism occurred in the past, giving rise to many of its more prominent geological features, observing evidence of subduction of tectonic plates while also noting the absence of orogeny resulting from the freezing of the mantle.
Surface.
Unlike Pluto's surface, which is composed of nitrogen and methane ices, Charon's surface appears to be dominated by the less volatile water ice. In 2007, observations by the Gemini Observatory of patches of ammonia hydrates and water crystals on the surface of Charon suggested the presence of active cryogeysers. Mutual eclipses of Pluto and Charon in the 1980s allowed astronomers to take spectra of Pluto and then the combined spectrum of the pair. By subtracting Pluto's spectrum from the total, astronomers were able to spectroscopically determine the surface composition of Charon. The northern regions of Charon are composed partially of hydrocarbons and tholins, whereas the lower latitudes are more diverse in composition. Charon also appears to have little, if any, atmosphere.
Photometric mapping of Charon's surface shows a latitudinal trend in albedo, with a bright equator band and darker poles. The south polar region is apparently darker than the north. The north polar region is dominated by a very large dark area informally dubbed "Mordor" by the "New Horizons" team. The Mordor Macula is distinctly red. Aside from Mordor, however, "New Horizons" imaged unexpectedly few other impact craters on Charon and found a youthful surface, indicating that Charon is probably geologically active. In particular, the southern hemisphere has fewer craters than the northern and is considerably less rugged, suggesting that a massive resurfacing event—perhaps prompted by the partial or complete freezing of an internal ocean—occurred at some point in the past and removed many of the earlier craters.
Charon's surface contains several large canyons from deep. These are northeast-southwest trending. One system of troughs and cliffs extends for 1050 km. One such graben is Serenity Chasma which is 60 km wide. Others include Macross Chasma which lines up with Serenity Chasma to form a belt that extends for . Other named chasmata are Tardis Chasma, Nostromo Chasma, and Argo Chasma which is 5 km deep.
Polar regions.
Charon's north polar region, Mordor Macula, is considerably darker and more reddish than the rest of its surface. The favored explanation for this phenomenon is that it was formed by condensation of gases that escaped from Pluto's atmosphere. In winter, the temperature is −258 °C, and these gases, which include nitrogen, carbon monoxide, and methane, condense into their solid forms; when these ices are subjected to solar radiation, they chemically react to form various reddish tholins. Later, when the area is again heated by the Sun as Charon's seasons change, the temperature at the pole rises to −213 °C, resulting in the volatiles sublimating and escaping Charon, leaving only the tholins behind. Over millions of years, the residual tholin builds up thick layers, obscuring the icy crust. The south polar region is also dark, and was imaged by New Horizons using sunlight reflected off Pluto.
Geological mapping.
A geomorphological map published in 2019 classifies Charon's surface into 16 types, including: blocky terrain, smooth terrain, elevated smooth terrain, rough terrain, mottled terrain, lobate aprons, and Mons, depressed material, craters and crater ejecta. Linear features were classified as catena, crater rim crest, depression margin, graben trace, groove, ridge crest, scarp base, scarp crest, or broad warp. Different time periods were labelled Ozian (older than 4 billion years, exposed in a region titled Oz Terra). The Vulcanian is next and features cryoflows, mainly near the equator in an area called Vulcan Planum. The Spokian is the period when impact craters have formed.
Interior.
Charon's volume and mass allow calculation of its density, , which is slightly lower than Pluto's and hence Charon has a slightly lower proportion of rock in its interior relative to Pluto. This difference is not as large as those of many other collisional satellites. Prior to "New Horizons", there were two conflicting theories about Charon's internal structure: some scientists thought it to be a differentiated body like Pluto, with a rocky core and an icy mantle, whereas others thought it would be uniform throughout. Evidence in support of the former position was found in 2007, when observations by the Gemini Observatory of patches of ammonia hydrates and water crystals on the surface of Charon suggested the presence of active cryogeysers. The fact that the ice was still in crystalline form suggested it had been deposited recently, because solar radiation would have degraded it to an amorphous state after roughly 30,000 years.


Penkill Formation

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


Hunton Group

The Hunton Group is a stratigraphic group in Oklahoma. It preserves fossils dating back to the Devonian period.


Friiesenrather Schichten Formation

The Friiesenrather Schichten Formation is a geologic formation in Germany.
Geological Period.
It preserves fossils dating back to the Devonian period.


Mont Aime Formation

The Mont Aime Formation is a geologic formation in France. It preserves fossils dating back to the Paleogene period.


Lauch Formation

The Lauch Formation is a geologic formation in Germany. It preserves fossils dating back to the Devonian period.


Paolo Costagli

Paolo Costagli (born in 1966) is an Italian jewellery designer and gemologist. Costagli is known for using hard-to-find colored gemstones, sophisticated color combinations and strong architectural shapes.
Early life.
Paolo Costagli studied at the private school Collegio Alla Querce in Florence. After his military service at the age of 21 he moved to the United States where he took the Graduate Gemologist course at the Gemological Institute of America in Santa Monica, California. After getting his gemologist degree Costagli went to Muzo, Colombia and worked for several months at the emerald mines. He then moved to Bogotá and worked there for a Japanese export company specializing in emeralds.
Career.
He returned to the United States and moved to New York City in 1991 and in 1993 started his own gem and antique jewelry business specializing in colored stones. He was buying signed vintage pieces from known jewelry designers and selling them in the trade. He learned the craft of jewelry making from the designers like René Boivin, Suzanne Belperron and Raymond Templier. In 1995 he started to design his own jewels. His early collections include "Florentine" (2001) inspired by the vivid colors seen in the Giardino dell'Iris garden in Florence, and "Brilliante" (2003), inspired by a tile pattern at the Doge's Palace in Venice.
In 2008 his "Brillante" bracelet was included into the permanent collection of Museum of Arts and Design.
In 2018 his company started a curated online trunk show for the first time. Now clients all over the world have access to the products and information behind it.
He is based in New York City on Madison Avenue.


Erdbach Limestone

The Erdbach Limestone is a geologic formation in Germany. It preserves fossils dating back to the Carboniferous period.


Hess Formation

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


Verneuil method

The Verneuil method (or Verneuil process or Verneuil technique), also called flame fusion, was the first commercially successful method of manufacturing synthetic gemstones, developed in the late 1883 by the French chemist Auguste Verneuil. It is primarily used to produce the ruby, sapphire and padparadscha varieties of corundum, as well as the diamond simulants rutile and strontium titanate. The principle of the process involves melting a finely powdered substance using an oxyhydrogen flame, and crystallising the melted droplets into a boule. The process is considered to be the founding step of modern industrial crystal growth technology, and remains in wide use to this day.
History.
Since the study of alchemy began, there have been attempts to synthetically produce precious stones, and ruby, being one of the prized cardinal gems, has long been a prime candidate. In the 19th century, significant advances were achieved, with the first ruby formed by melting two smaller rubies together in 1817, and the first microscopic crystals created from alumina (aluminium oxide) in a laboratory in 1837. By 1877, chemist Edmond Frémy had devised an effective method for commercial ruby manufacture by using molten baths of alumina, yielding the first gemstone-quality synthetic stones. The Parisian chemist Auguste Verneuil collaborated with Frémy on developing the method, but soon went on to independently develop the flame fusion process, which would eventually come to bear his name.
One of Verneuil's sources of inspiration for developing his own method was the appearance of synthetic rubies sold by an unknown Genevan merchant in 1880. These "Geneva rubies" were dismissed as artificial at the time, but are now believed to be the first rubies produced by flame fusion, predating Verneuil's work on the process by 20 years. After examining the "Geneva rubies", Verneuil came to the conclusion that it was possible to recrystallise finely ground aluminium oxide into a large gemstone. This realisation, along with the availability of the recently developed oxyhydrogen torch and growing demand for synthetic rubies, led him to design the Verneuil furnace, where finely ground purified alumina and chromium oxide were melted by a flame of at least , and recrystallised on a support below the flame, creating a large crystal. He announced his work in 1902, publishing details outlining the process in 1904.
By 1910, Verneuil's laboratory had expanded into a 30-furnace production facility, with annual gemstone production by the Verneuil process having reached in 1907. By 1912, production reached , and would go on to reach in 1980 and in 2000, led by Hrand Djevahirdjian's factory in Monthey, Switzerland, founded in 1914. The most notable improvements in the process were made in 1932, by S. K. Popov, who helped establish the capability for producing high-quality sapphires in the Soviet Union through the next 20 years. A large production capability was also established in the United States during World War II, when European sources were not available, and jewels were in high demand for their military applications.
The process was designed primarily for the synthesis of rubies, which became the first gemstone to be produced on an industrial scale. However, the Verneuil process could also be used for the production of other stones, including blue sapphire, which required oxides of iron and titanium to be used in place of chromium oxide, as well as more elaborate ones, such as star sapphires, where titania (titanium dioxide) was added and the boule was kept in the heat longer, allowing needles of rutile to crystallise within it. In 1947, the Linde Air Products division of Union Carbide pioneered the use of the Verneuil process for creating such star sapphires, until production was discontinued in 1974 owing to overseas competition.
Despite some improvements in the method, the Verneuil process remains virtually unchanged to this day, while maintaining a leading position in the manufacture of synthetic corundum and spinel gemstones. Its most significant setback came in 1917, when Jan Czochralski introduced the Czochralski process, which has found numerous applications in the semiconductor industry, where a much higher quality of crystals is required than the Verneuil process can produce. Other alternatives to the process emerged in 1957, when Bell Labs introduced the hydrothermal process, and in 1958, when Carroll Chatham introduced the flux method. In 1989 Larry P Kelley of ICT, Inc. also developed a variant of the Czochralski process where natural ruby is used as the 'feed' material.
Process.
One of the most crucial factors in successfully crystallising an artificial gemstone is obtaining highly pure starting material, with at least 99.9995% purity. In the case of manufacturing rubies, sapphires or padparadscha, this material is alumina. The presence of sodium impurities is especially undesirable, as it makes the crystal opaque. But because the bauxite from which alumina is obtained is most likely by way of the Bayer process (the first stage of which introduces caustic soda in order to reduce the Al2O3) particular attention must be paid to the feedstock.
Depending on the desired colouration of the crystal, small quantities of various oxides are added, such as chromium oxide for a red ruby, or ferric oxide and titania for a blue sapphire. Other starting materials include titania for producing rutile, or titanyl double oxalate for producing strontium titanate. Alternatively, small, valueless crystals of the desired product can be used.
This starting material is finely powdered, and placed in a container within a Verneuil furnace, with an opening at the bottom through which the powder can escape when the container is vibrated. While the powder is being released, oxygen is supplied into the furnace, and travels with the powder down a narrow tube. This tube is located within a larger tube, into which hydrogen is supplied. At the point where the narrow tube opens into the larger one, combustion occurs, with a flame of at least at its core. As the powder passes through the flame, it melts into small droplets, which fall onto an earthen support rod placed below. The droplets gradually form a sinter cone on the rod, the tip of which is close enough to the core to remain liquid. It is at that tip that the seed crystal eventually forms. As more droplets fall onto the tip, a single crystal, called a "boule", starts to form, and the support is slowly moved downward, allowing the base of the boule to crystallise, while its cap always remains liquid. The boule is formed in the shape of a tapered cylinder, with a diameter broadening away from the base and eventually remaining more or less constant. With a constant supply of powder and withdrawal of the support, very long cylindrical boules can be obtained. Once removed from the furnace and allowed to cool, the boule is split along its vertical axis to relieve internal pressure, otherwise the crystal will be prone to fracture when the stalk is broken due to a vertical parting plane.
When initially outlining the process, Verneuil specified a number of conditions crucial for good results. These include: a flame temperature that is not higher than necessary for fusion; always keeping the melted product in the same part of the oxyhydrogen flame; and reducing the point of contact between the melted product and support to as small an area as possible. The average commercially produced boule using the process is in diameter and long, weighing about . The process can also be performed with a custom-oriented seed crystal to achieve a specific desired crystallographic orientation.
Crystals produced by the Verneuil process are chemically and physically equivalent to their naturally occurring counterparts, and strong magnification is usually required to distinguish between the two. One of the telltale characteristics of a Verneuil crystal is curved growth lines (curved striae) formed as the cylindrical boule grows upwards in an environment with a high thermal gradient; the equivalent lines in natural crystals are straight. Another distinguishing feature is the common presence of microscopic gas bubbles formed due to an excess of oxygen in the furnace; imperfections in natural crystals are usually solid impurities.


Jindongornipes

Jindongornipes was a Cretaceous bird ichnogenus. Similar fossil footprints have been discovered in the Dunvegan Formation of British Columbia. These were among the first known Cretaceous fossil bird tracks in western Canada.


Cumberland Formation

The Cumberland Formation is a geologic formation in Nova Scotia. It preserves fossils dating back to the Carboniferous period.


Hoh River

The Hoh River is a river of the Pacific Northwest, located on the Olympic Peninsula in the U.S. state of Washington. About long, the Hoh River originates at the Hoh Glacier on Mount Olympus and flows west through the Olympic Mountains of Olympic National Park and Olympic National Forest, then through the foothills in a broad valley, emptying into the Pacific Ocean at the Hoh Indian Reservation. The final portion of the Hoh River's course marks the boundary between the coastal segment of Olympic National Park and Olympic National Forest, the Hoh Indian Reservation.
The Hoh's drainage basin is . Its discharge, or streamflow, has considerable seasonal variation, with summer streamflow averaging about one-third that of winter flows.
The Hoh is a glacial river fed by glaciers on Mount Olympus, such as the Blue Glacier. The glaciers grind rock into a fine glacial flour which turns the Hoh River a milky slate blue color. The river valley is generally broad and relatively flat, causing the glacial sediments to settle out, creating extensive gravel bars, river meanders, and the many side channels characteristic of a braided river.
One of the road entrances to Olympic National Park is on the Hoh River. The Hoh River Campground is the trailhead of the Hoh River Trail, which follows the river through the Hoh Rain Forest from the campground to Mount Olympus. Logjams are common, resulting in quiet pools and new river channels being formed.
The river's name and the name of the Hoh tribe both ultimately come from the Quinault placename /húxw/.
Course.
The source of the Hoh River is meltwater from the Hoh Glacier on the northeast side of Mount Olympus. The river flows north then west, curving around the north side of the mountain. It collects headwater tributaries from other glaciers on Mount Olympus such as the Ice River, which flows from the Ice River Glacier, and Glacier Creek, which flows from Blue Glacier and White Glacier. Mount Tom Creek, a tributary which joins the Hoh farther downstream, flows from the White Glacier as well. Other headwater tributaries include Elkhorn Creek and Cream Lake Creek, both of which flow west from the Bailey Range of the Olympic Mountains. Ice River joins shortly below Cream Lake Creek. A few miles below that the Hoh River begins to flow more directly west. Glacier Creek joins from the south, from Mount Olympus. About a mile below Glacier Creek, at approximately Hoh river mile 48, the valley broadens and the river begins to take on braided characteristics. Falls Creek joins from the south, then Slate Creek and Hoh Creek from the north.
Olympus Ranger Station, a National Park Service cabin, is located on the north side of the river at approximately river mile 45, near the junction of the Hoh River Trail and the Hoh Lake Trail. At river mile 42 the Happy Four backcountry camping area is located along the river trail. Below that the tributary Cougar Creek joins from the north, then Mount Tom Creek from the south. Jackson Creek joins from the south at approximately river mile 37 near the Hoh Rain Forest Visitor Center and campground. The Visitor Center is located at the end of Upper Hoh Road and the beginning of the Hoh River Trail. The Upper Hoh Road runs east from U.S. Highway 101, paralleling the Hoh River from Willoughby Creek Campground to the national park. In the region near the national park boundary the Hoh River occupies a U-shaped valley with a flat bottom about one mile across. Mountain slopes rise steeply on either side.
The Hoh River continues flowing west, collecting numerous tributary streams, the most important being the South Fork Hoh River, which joins the main Hoh at about river mile 31. About a mile below the South Fork confluence the Hoh River leaves Olympic National Park. It continues to flow west through a widening valley surrounded by low mountains and foothills. Ranches occupy parts of the valley and land ownership is generally private. Owl Creek and Maple Creek join from the south. The Hoh makes a small northward bend, skirting the edge of, and briefly entering Olympic National Forest. Elk Creek joins from the south, then Alder Creek from the north, then Winfield Creek from the south, after which the Hoh River flows through a large horseshoe bend located at about river mile 15. Hell Roaring Creek joins the horseshoe bend from the north. Three campgrounds are sited along the river upstream from the horseshoe bend, including Minnie Peterson, Willoughby Creek, and Hoh Oxbow. All three are managed by Washington State Department of Natural Resources (DNR). Hoh Ox Bow Campground is located just west of the horseshoe bend near where U.S. Highway 101 crosses the river. Highway 101 follows the river on the south side. The small Oil City Road follows the Hoh River on the north side to the river's mouth. Cottonwood Campground, another DNR site, is on the north side of the Hoh River, accessed by Oil City Road.
Below the horseshoe bend the Hoh River begins to meander widely through a broad and flat floodplain. In its final miles the Hoh River collects the tributaries Fletcher Creek and Fossil Creek. Highway 101 leaves the river and heads south. About two miles from its mouth the Hoh River becomes the boundary between the Hoh Indian Reservation, on the south, and the coastal part of Olympic National Park on the north. The former settlement of Oil City is located on the north side of the Hoh River about a half mile from its mouth. A large headland peninsula called Hoh Head is located on the Pacific coast a few miles north of the river's mouth.
South Fork.
The South Fork Hoh River originates at , flowing from Hubert Glacier and other small glaciers on the south side of Mount Olympus. It flows generally west through Olympic National Park collecting many tributary streams. At about river mile 11 it enters a broad glacially carved U-shaped valley and becomes braided. The South Fork leaves Olympic National Park at approximately river mile 4, entering Olympic National Forest. It turns slightly northwest and joins the main Hoh River at approximately Hoh river mile 31. South Fork Campground, managed by Washington State DNR, is located on the South Fork. The road to the campground continues up the South Fork Hoh River to the South Fork Hoh Trailhead, just west of the national park boundary.
History.
The indigenous people of the Hoh River are known as the Hoh but they call themselves "chalat'". Their name for the Hoh River is "chalak'ac'it".
The earliest documented encounter between Europeans and the Hoh people occurred in 1787 when the British fur trader Charles William Barkley, captain of the "Imperial Eagle", dispatched a boat up the Hoh River to trade with the natives. The boat's crew of six were killed by the Hoh people, according to European histories. The incident led to the naming of Destruction Island. Barkley named the river Destruction River, but the name became attached to the island instead. The Hoh people deny the story, saying they never massacred ship-wrecked sailors.
In 1808 the Russian American Company set two vessels south from Russian America as part of an effort to expand Russian control south to the Columbia River and beyond. One of the vessels, the schooner "Sv. Nikolai" ran aground at Rialto Beach, north of the Quillayute River. Tension between the crew and the local Hohs led to battle. The Russians fled south along the coast to the mouth of the Hoh River where many were captured and taken captive by the Hoh people. Those who evaded capture fled up the Hoh River. They built a small blockhouse and survived into the winter. In February they surrendered to the Hoh tribe at the mouth of the Hoh River. The captives were exchanged and traded among the coastal tribes, with most ending up with the Makah in the Neah Bay area. In 1810 the "Lydia", commanded by Captain T. Brown, an American working for the Russian American Company, sailed into Neah Bay. The thirteen surviving captives being held by the Makah were ransomed by Captain Brown, who then returned them to Sitka.
In the 1850s Isaac Stevens, the first governor of Washington Territory, began negotiations with the tribes of the Olympic Peninsula with the goal of obtaining land cessions and creating Indian reservations. In 1855 a treaty was signed by representatives of the Quinault, Queets, Quileute, and Hoh. The negotiations were done in the trade pidgin language Chinook Jargon. The treaty, known as the Treaty of Olympia (or the Quinault River Treaty), was ratified by Congress in 1859. Its terms included the cession of most of the western Olympic Peninsula to the U.S. federal government with a reserve to be determined later. The Quinault Indian Reservation was established in 1863 and the treaty signature tribes were expected to move there. The Hoh, however, refused to move. In 1872 the Indian agent R.H. Milroy explained that the Hoh did not believe they had agreed to cede their land and that the treaty signed had been explained to them as being an agreement about keeping peace with U.S. citizens and allowing them to enter the Hoh's territory and trade for furs. In 1893 President Grover Cleveland signed an executive order establishing the Hoh Reservation on the south side of the mouth of the Hoh River.
Early pioneers wishing to settle in the Hoh River valley faced numerous challenges including the dense forest and enormous trees, regular large-scale flooding, isolation from markets, and the impracticality of navigating the Hoh River due to its swift current, floods, and frequent logjams. Nevertheless, land relatively far upriver was settled. The area now within Olympic National Park was never inhabited by non-indigenous people. By 1900 the population in the Hoh River Valley was enough to warrant two post offices, one established in 1897, the other in 1904. Over time the population dwindled. By 1919 there were few people left. Abandoned structures rapidly deteriorated in the wet environment. The few historic structures that used to exist in the Hoh River Valley are entirely gone today.
On the north side of the mouth of the Hoh River, across from the Hoh Indian Reservation, the town of Oil City was established in 1911 by Frank W. Johnson and the Olympic Oil Company. Natives had already discovered the oil, which seeps to the surface. This was to be a deep water oil port. Many of the lots were bought on the hopes of oil prosperity, but some were used for vacation homes. Oil drilling operations were conducted by the Milwaukee Oil Co., the Washington Oil Co., the Jefferson Oil Co. and others in the surrounding areas. No significant commercial oil reserves were found. Later, two-thirds of the platted city were returned to the state which now forms part of the Olympic Wilderness Park. http://www.historylink.org/index.cfm?DisplayPage=output.cfm&file_id=7446
Natural history.
A significant part of the Hoh River flows through the Hoh Rainforest, a relatively rare example of a temperate rain forest. Abundant winter rainfall results in a lush green canopy of coniferous and deciduous trees, often covered with mosses and ferns. Annual precipitation is . According to the National Park Service the Hoh Rain Forest is one of the finest remaining examples of temperate rain forest in the United States. It is one of the most popular destinations of Olympic National Park. Giant Western Hemlock, Douglas-fir, Thuja plicata (Western Red Cedar), and Sitka Spruce trees dominate the landscape, while ferns and mosses cloak the trees and forest floor. Fallen trees often become nurse logs.
When Olympic National Park was created in 1938 one of its primary objectives was to protect the herds of Roosevelt elk. Today about 400 of the park's 4,000–5,000 elk live in the Hoh River valley.
The Hoh River supports a variety of salmonid fish, including spring and fall chinook, coho salmon, winter and summer steelhead, and sea-run coastal cutthroat trout. There are also smaller numbers of chum and sockeye salmon. The Hoh River fishery is managed by the Hoh tribe in cooperation with the Washington Department of Fish and Wildlife .
Land use.
Land administration within the Hoh River's watershed, approximately, is 57.6% National Park Service (), 24.4% state (), 17.6% private (), 0.22% National Forest (), and 0.21% Hoh Indian Reservation ().
Recreation.
The Hoh River Trail, managed by the National Park Service, begins at the national park's Hoh Rain Forest Visitor Center at the end of the Upper Hoh Road. The trail follows the Hoh River east into the heart of the park. After it reaches Glacier Meadows near Mount Olympus's Blue Glacier. The Hoh River Trail begins at an altitude of about and the trail is mostly flat for about , after which it ascends steeply to Glacier Meadows, altitude . The trail passes through the Hoh Rain Forest, a temperate rain forest, and, closer to Mount Olympus, montane forests and subalpine meadows. There are a number of backcountry campsites along the trail. Mountaineers wishing to climb Mount Olympus typically use the Hoh River Trail to reach the mountain. The climb requires experience with glacier travel and crevasse rescue skills.
The Hoh Lake Trail branches off from the Hoh River Trail near the Olympus Ranger Station and ascends to Hoh Lake and Bogachiel Peak, then across High Divide into the Sol Duc River valley.
The Oil City Trail, managed by Olympic National Park, begins on the north side of the mouth of the Hoh River and runs about a mile to the Pacific coast. People can hike north along the coast to Hoh Head and beyond.


Bingham Mine Formation

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


Bohlen Formation

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


Cajon Valley Beds

The Cajon Valley Beds is a sedimentary geologic formation in the El Cajon Valley of southwestern San Diego County, California.
It preserves fossils dating back to the Neogene period of the Cenozoic Era.


Maximum flooding surface

In sequence stratigraphy, a maximum flooding surface is the surface that marks the transition from a transgression to a regression. Maximum flooding surfaces are abbreviated by mfs, synonyms for them include final transgressive surface, surface of maximum transgression and maximum transgressive surface.
Facies.
Maximum flooding surfaces are often associated with deep water facies, which corresponds to the deposition of fine grains in siliciclastic systems. They also tend to display some degree of condensation due to lower deposition rates.


Timeline of paleontology in Michigan

This timeline of paleontology in Michigan is a chronologically ordered list events in the history of paleontological research occurring within or conducted by people from the U.S. state of Michigan.
19th century.
1830s.
1839
1870s.
1877
20th century.
1900s.
1903
1910s.
1914
1920s.
1923
1925
1927
1930s.
1930
1940s.
1940
1949
1950s.
1953
1960s.
1961
1962
1963
1964
1965
21st century.
2000s.
2002


Polybaric melting

In basalt petrogenesis polybaric melting implies that liquids are incrementally separated from residues across a range of pressures and subsequently mix and move through the mantle without equilibrating with surrounding mantle minerals. This model was developed to better approximate basalt petrogenesis in modeling and experiments. It usually involves polybaric near-fractional melting (e.g., constant intergranular porosity in the rock during melting and/or reactive porous flow in melt extraction) along an adiabatic path.
In practice, petrologic models employ advanced forms of the polybaric concept for greater physical plausibility. Such models incorporate interconnected porosity to facilitate buoyant flow of liquids from lherzolitic or harzburgitic assemblages, such as replacive dunite formation in migration channels. The porosity has to consist of at least two or a continuum of size scales to account for U-series disequilibria and major/trace element chemistry of abyssal peridotites.
The realization that polybaric near-fractional melting may be the dominant form of basalt petrogenesis was a consequence of difficulties with a simpler paradigm involving only a chemically distinct primary melt, in equilibrium with residual mantle minerals, undergoing fractionation (and transportation) to yield basaltic and mid-ocean ridge basalt (MORB) lava. The assumption of a unique primary melt led to the expectation that chemical and mineral characterization of primitive glasses associated with a basalt would constrain the residual mantle mineral assemblage, temperature, and pressure of the (presumed) primary melt. However, such "inverse" modeling as well as "forward" peridotite melting experiments failed to fully constrain underlying processes, necessitating the use of polybaric near-fractional melting.
It is possible to incorporate polybaric near-fractional melting considerations into predictive algorithms such as pMELTS and MAGPOX.


Falun de Pierrefitte

The Falun de Pierrefitte is a geologic formation in France. It preserves fossils dating back to the Paleogene period.


Quartermaster Formation

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


Arnside Bore

The Arnside Bore is a tidal bore on the estuary of the River Kent in England, United Kingdom.
The bore occurs at high tides, especially spring tides, where the incoming tide of Morecambe Bay narrows into the river estuary, opposite the village of Arnside.


Gres de Carriers

The Gres de Carriers is a geologic formation in France. It preserves fossils dating back to the Devonian period.


Strain partitioning

Strain partitioning is commonly referred to as a deformation process in which the total strain experienced on a rock, area, or region, is heterogeneously distributed in terms of the strain intensity and strain type (i.e. pure shear, simple shear, dilatation). This process is observed on a range of scales spanning from the grain – crystal scale to the plate – lithospheric scale, and occurs in both the brittle and plastic deformation regimes. The manner and intensity by which strain is distributed are controlled by a number of factors listed below.
Influencing factors.
All four of these factors below may individually or in combination contribute toward the distribution of strain. Therefore, each of these factors must be taken into consideration when analyzing how and why strain is partitioned:
Subdivisions.
Strain partitioning across the literature is diverse and has been divided into three subdivisions according to the American Geological Institute.
Superposition of individual strain components.
The superposition of individual strain components can be expressed at the tectonic scale involving oblique convergent margins and transpression / transtension tectonic regimes.
Oblique convergent margins.
Convergent margins where the angle of subduction is oblique will often result in the partitioning of strain into an arc parallel component (accommodated by strike slip faults or shear zones) and an arc normal component (accommodated through thrust faults). This occurs as a response to shear stress exerted at the base of the overriding plate that is not perpendicular to the plate margin.
Example: Himalayan Orogen.
The Himalaya is a strain partitioned orogen which resulted from the oblique convergence between India and Asia. Convergence between the two landmasses persists today at a rate of 2 cm/yr. The obliquity of plate convergence increases toward the western portion of the orogen, thus inducing a greater magnitude of strain partitioning within the western Himalaya than in the central.
The table below shows relative velocities of India's convergence with Asia. The lateral variability in velocity between the central and marginal regions of the orogen suggest strain is partitioned due to oblique convergence.
Table reference:
Transpression and transtension.
Strain partitioning is common within transpressive and transtensive tectonic domains. Both regimes involve a component of pure shear (transpression – compressive, transtension – extensive) and a component of simple shear. Strain may be partitioned by the development of a strike slip fault or shear zone across the actively deforming region.
Example: Coast Mountains British Columbia.
The Coast Mountains of British Columbia are interpreted as a transpressive orogen which formed during the Cretaceous. Oblique subduction induced the development of several shear zones which strike parallel to the orogen. The presence of these shear zones suggest that strain is partitioned within the Coast Orogen which resulted in horizontal translation of terranes for several hundred kilometers parallel to the orogen.
Strain factorization.
Strain factorization is a mathematical approach to quantify and characterize the variation of strain components in terms of the intensity and distribution that produces the finite strain throughout a deformed region. This effort is achieved through matrix multiplication. Refer to the figure below to conceptually visualize what is obtained through strain factorization.
Influence of rock material rheology.
At the grain and crystal scale, strain partitioning may occur between minerals (or clasts and matrix) governed by their rheological contrasts. Constituent minerals of differing rheological properties in a rock will accumulate strain differently, thus inducing mechanically preferable structures and fabrics.
Example.
Rocks that contain incompetent (mechanically weak) minerals such as micas and more competent (mechanically stronger) minerals such as quartz or feldspars, may develop a shear band fabric. The incompetent minerals will preferentially form the C-surfaces and competent minerals will form along the S-surfaces.
Individual deformation mechanisms.
Strain partitioning is also known as a procedure for decomposing the overall strain into individual deformation mechanisms which allowed for strain to be accommodated. This approach is performed from geometrical analysis of rocks on the grain – crystal scale. Strain partitioning of deformation mechanisms incorporates those mechanisms which occur both simultaneously and/or subsequently as tectonic conditions evolve, as deformation mechanisms are a function of strain rate and pressure-temperature conditions. Performing such a procedure is important for structural and tectonic analysis as it provides parameters and constraints for constructing deformation models.


Farne Group

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


Osbourne Canyon Formation

The Osbourne Canyon Formation is a geologic formation in California. It preserves fossils dating back to the Permian period.


Notch Peak Formation

The Notch Peak Formation is a geologic formation in Utah. It preserves fossils dating back to the Cambrian period.
The Notch Peak Formation has three recognized members: "Hellnmaria", "Red Tops", and "Lava Dam Members" (in ascending order), all of which are composed of limestone and dolomite. It is named after the prominent peak of the same name in the House Range of Utah's West Desert, which is its type locality.


Paul Werner Gast

Paul Werner Gast (September 11, 1930 – May 16, 1973) was an American geochemist and geologist.
He was born in Chicago, and attended Wheaton College, Illinois, whence he graduated in 1952. He earned a Ph.D. from Columbia University in 1957. After graduation, he taught at the University of Minnesota until 1965 when he became professor of geology at Columbia.
In 1969 Paul Gast assumed leadership of the geo-science management of the Manned Spacecraft Center in preparation for Apollo mission sample return from the Moon. He served as chief scientist of the Apollo Lunar Science Staff. He was one of the science consultant group known unofficially as the "Four Horsemen", along with Jim Arnold, Bob Walker and Gerry Wasserburg.
He died at the age of 43, being survived by his wife, Joyce Rinehart, and two sons and a daughter. During his career he pioneered the study of rare earth elements in examining the crust, mantle, and interior of the planet. He led the development of the use of rubidium-strontium and uranium-lead radiometric dating methods for rocks, particularly for samples returned from the Moon. His examinations of trace elements resulted in new understanding of how volcanic fluids originate.
Works.
He was also co-author of multiple papers on Geology.


Eckfeld Formation

The Eckfeld Formation is a geologic formation in Germany. It preserves fossils dating back to the Devonian period.


Williamsport Formation

The Williamsport Sandstone is a sandstone geologic formation in West Virginia, Virginia, Pennsylvania, and Maryland. the formation includes the Cedar Creek Limestone member. Near Cumberland, Maryland it includes the Cedar Creek Limestone member. It preserves fossils dating back to the Silurian period.


Moine Supergroup

The Moine Supergroup is a sequence of Neoproterozoic metamorphic rocks that form the dominant outcrop of the Scottish Highlands between the Moine Thrust Belt to the northwest and the Great Glen Fault to the southeast. The sequence is metasedimentary in nature and was metamorphosed and deformed in a series of tectonic events during the Late Proterozoic and Early Paleozoic. It takes its name from "A' Mhòine", a peat bog in northern Sutherland.
Distribution.
The main outcrop of the Moine series lies northwest of the Great Glen Fault, structurally above the Moine Thrust to the west forming what is known as the Northern Highlands Terrane. A smaller area of similar rocks that are correlated with these, outcrop within the 'Grampian Terrane' to the southeast of the Great Glen. Moinian rocks are also recognised on Mull, Orkney and Shetland.
Stratigraphy.
The Moine Supergroup has been subdivided into different groups or divisions. The relationship between individual groups in terms of age and stratigraphic equivalence is generally unclear, as they are unfossiliferous due to their age and metamorphic state. They are mostly described in tectonostratigraphic terms referring to their position relative to major Caledonian thrust structures. The Moine is lithologically monotonous, being dominated by psammites (metamorphosed sandstones), making lithostratigraphic correlation extremely difficult.
Morar Group.
This group lies tectonically above the Moine Thrust but below the Sgurr Beag or Naver thrusts. Large slices of Lewisian-type gneisses occur within this group, locally a basal conglomerate is preserved, confirming the unconformable nature of the contact between them.
East Sutherland Moine.
This group lies tectonically above the Naver Thrust. The upper boundary of this group in not seen.
Glenfinnan Group.
This group lies tectonically above the Sgurr Beag Thrust and below the Loch Eil Group. There is evidence of a true stratigraphic transition between these two groups in some areas. Slices of Lewisian-type gneisses are found above the Sgurr Beag thrust and are interpreted to represent pieces of basement to the group incorporated during the Caledonian orogeny.
Loch Eil Group.
This group lies above the Glenfinnan Group. The upper boundary of this group is not seen. Towards the southwestern end of its outcrop the Group consists of widespread psammites within which are identified a lower Kinlocheil Quartzite Formation which is anything up to 1.5km in thickness, an overlying Glen Gour Quartzite and Pelite Formation of 500-800m thickness and above this, the 100-650m thick Stronchreggan Formation. A Tarvie Psammite Formation is recorded in the Strathconon and Strathglass districts.
Dava and Glen Banchor successions.
These sequences lie within the Grampian Terrane and are classed as subgroups within a newly established Badenoch Group. They have been tentatively correlated with the Moine, which they resemble lithologically and with which they share a metamorphic history. These successions may have a basement-cover relationship with the Grampian Group, the lowermost part of a younger metamorphic sequence, the Dalradian Supergroup.
Age.
Age of sedimentation.
The complete lack of fossils is consistent with a Precambrian age for the sequence. This is also shown by the age of the earliest known intrusions that cut the sequence, dated at around 870 Ma. There is also no evidence of the sequence being affected by the 1300-1000 Ma Grenville orogeny. This together suggests an early Neoproterozoic sedimentation age. A possible correlation with the lithologically similar Torridon Group, an unmetamorphosed sequence of similar age found beneath the Moine Thrust, remains unproven.
Age of metamorphism.
Knoydartian.
Radiometric dating of micas from deformed pegmatites provided the first evidence of a Precambrian metamorphic event with ages of 690-750 Ma. With improved techniques, the timing of this event has been constrained to ca. 820-790 Ma, with later ages relating to cooling.
Caledonian.
It was originally thought that the Highland and Grampian terranes had distinct geological histories as it appeared that only the latter had been affected by the Ordovician age Grampian metamorphic event. Although it is now known that Moine was also affected by the Grampian event, the dominant metamorphic event is of late Silurian age, associated with the Scandian orogeny.
Structure.
Pre-Knoydartian.
Despite the degree of both metamorphism and deformation in the Moine sequence, it has been possible to identify variations in the original depositional thickness of the various groups. These thickness variations have been interpreted in terms of half-grabens within an overall rift setting.
Knoydartian.
The cause of the Knoydartian metamorphic event has yet to be established. Some authors interpret this to be a result of a high heatflow due to extensional tectonics, while others interpret it to be an orogenic event.
Caledonian.
The main tectonic event recorded in the Moine rocks is the Late Silurian Scandian event. The main structures formed are regionally significant thrusts, the Moine Thrust, the Naver Thrust and the Sgurr Beag Thrust. The thrusts that lie structurally above the Moine Thrust Zone have all been folded and deformed in a ductile fashion.
The final stages of the Caledonian orogeny involved sinistral strike-slip faulting. The Great Glen Fault is the largest of the structures formed at this time, but other major faults occur within the Moine outcrop including the Strathconon and Strathglass faults.
Igneous rocks.
Basic intrusions.
The Moine sequence is cut by numerous small metabasic intrusions, particularly in the Glenfinnan and Loch Eil groups. They have a tholeiitic chemistry, consistent with intrusion into a rift setting.
Early granitic intrusions.
The Moinian rocks of Ross-shire and Sutherland are intruded by a distinctive set of granitic sheets, which give latest Proterozoic intrusion ages in the range 611-588 Ma. It has been suggested that these granites formed associated with rifting.
'Newer' granites.
The main suite of granites intruded into the Moine are the Late Silurian to Early Devonian age 'newer granites' that occur throughout the Scottish Caledonides.


Bringewood Beds

The Bringewood Beds is a geologic formation in England. It preserves fossils dating back to the Silurian period.


Oakville Formation

The Oakville Formation is a geologic formation in Texas. It preserves fossils dating back to the Neogene period.


Chris Ballentine

Dr. Chris Ballentine is the Chair of geochemistry and head of department of the Department of Earth Sciences at the University of Oxford in the United Kingdom. He uses properties of the noble gases to understand the origin and evolution of Earth's atmosphere and mantle.
Career.
Ballentine earned his Ph.D. at the University of Cambridge in 1992. He went on to hold research positions at the Paul Scherrer Institut, Switzerland, the University of Michigan, and ETH Zurich, Switzerland. From 2001 to 2013, he held positions at the University of Manchester before joining the faculty at the University of Oxford.
Ballentine has held the vice president, president, and past president positions with the European Association of Geochemistry. He is a member of the Board of Governors of the Oxford Museum of Natural History and the American Geophysical Union, as well as a former scientific steering committee member for the Deep Carbon Observatory. In 2008, he won the Geological Society of London Bigsby medal for significant contributions to geology. The AGU chose Ballentine as a Fellow in 2013, and in 2016, he won the Eni Award, given to researchers who make advanced scientific breakthroughs in the field of energy, for "New Frontiers of Hydrocarbons".
Research initiatives.
Ballentine has shown that by measuring noble gas isotopes, he can identify and quantify the processes controlling the origin, migration, and interaction of subsurface water, hydrocarbons, and fluids.
He has applied noble gas tools and principles to understand how natural gas fields form inside Earth, the role of groundwater in forming hydrocarbon reservoirs, and the origins of different gases on the planet. Ballentine also has developed quantitative techniques to understand how carbon dioxide behaves in the subsurface, including its role in the crustal carbon cycle, and how carbon-rich fluids have supported subsurface life over geological timescales.


Camnant Mudstone

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


Flammkohlenpartie Formation

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


Dornick Hills Group

The Dornick Hills Group is a geologic group in Oklahoma. It preserves fossils dating back to the Carboniferous period.


Coils Creek Limestone

The Coils Creek Limestone is a geologic formation in Nevada. It preserves fossils dating back to the Devonian period.


Saddle (geology)


Apatopus

Apatopus is an ichnogenus, or a name based on footprints, that may have been from a phytosaur. The trackmaker lived in the early Triassic. It was named by Baird in 1957.
Of special relevance in regard to its phytosaurian identity is the fact that the tracks are positioned in a way that indicates that the limbs were held directly under the body, a gait known in true archosaurs like crocodiles and dinosaurs but previously thought absent in phytosaurs. This raises the question of whereas this trait was shared by the last common ancestor between archosaurs and phytosaurs or if it evolved independently between these groups.


Wannagan Creek site

The Wannagan Creek site is a fossil site found just west of the South Unit of Theodore Roosevelt National Park of North Dakota, USA. The site is Paleocene in age, approximately 60 million years old. Paleontologists of the Science Museum of Minnesota have studied the site for nearly thirty years. The site is thought to represent a paleoenviroment of subtropical swampy lowland and forests. Preservation is excellent for both the flora and fauna of the site. Trace fossils of crocodilians and other vertebrates have also been discovered.
Topography/Geology.
The topography of the site is that of a badland, due to the downcutting of the Little Missouri River. The rock units are likely sediments derived from the Laramide orogeny deposited in an ecosystem dominated by rivers, streams, ponds, lakes, and swamps.
The Wannagan Site is found in the upper portion of the Tongue River Formation (formerly Bullion Creek Formation). The rocks of this deposit, reaching a thickness of over 60 m, consist of yellow to tan, poorly lithified claystones, mudstones, and siltstones with a lesser amounts of interbedded fine-grained sandstones and lignite. The site is overlain by the Sentinel Butte Formation. This formation is generally gray to brown in color but is similar in lithology to the Tongue River. The Sentinel Butte is roughly 90 m thick. The contact between the two formations is roughly 6 m above the site. The Sentinel Butte contains an extensive stump-bearing petrified wood bed above the contact at the site.
Fauna.
Many mammals are found at Wannagan. All are small compared to modern mammals, the largest being sheep-sized. Preserved mammals include a squirrel-like primitive primate and "Ptilodus", an arboreal multituberculate. The largest mammal at the site is the condylarth herbivore "Phenacodus". An additional mammal fossil is "Protictis", a weasel sized member of Viverridae that may have hunted on the forest floor.
Reptiles are the dominant animal type preserved at Wannagan. The largest animal (~4 meters [13 ft] in length) found at the site is the eusuchian crocodilian "Borealosuchus formidabilis" (formerly known as "Leidyosuchus formidabilis"). "B. formidabilis" is also thought to be the apex predator of the fauna. The second largest reptile is the champsosaur "Champsosaurus gigas". "C. gigas" is unusual among Paleocene reptiles in that it is larger than its known Mesozoic ancestors: 3 meters (10 ft) in length versus 1.5 meters (4.5 ft) for the largest Cretaceous champsosaurs. Reptiles as a whole decreased in size after the Cretaceous–Paleogene extinction event. Other reptiles include soft-shelled turtles, varanid lizards, a small alligatorid called "Wannaganosuchus", palaeophid snakes, and the snapping turtle-like "Protochelydra zangerli".
Birds from Wannagan include an ibis, an unnamed water bird, and a plover-like shore bird. The two types amphibians found at Wannagan are the giant salamander "Piceorpeton willwoodense" and frogs. Fish include fossil "Esox", freshwater rays, gar, and bowfin. Additionally, the dragonfly "Gomphaeschna schrankii" and the mayfly "Ephemeropteran" have been found.
Flora.
The flora of Wannagan is quite well preserved in some cases, with evidence of insect feeding found on many fossils. Most of the fossils have modern equivalents. The list of trees at Wannagan Creek include palms, ginkgo trees, bald cypress, dogwoods, oaks, elms, fig trees, magnolias, dawn redwoods, hackberries, sassafras, sycamores, cherries, mulberries, and cycads. Additional plants found at the site are grape vines, lotus, bur-reeds, cattails, and water-plantago.


C. E. A. Wichmann

Carl Ernst Arthur Wichmann (9 April 1851 Hamburg – 28 November 1927 Hamburg) was a German geologist and mineralogist. He was professor in geology at Utrecht University from 1879 to 1921, where he founded the geological institute. His daughter was the jurist and anarchist-socialist Clara Wichmann, his son the artist and fascist Erich Wichmann.
Arthur Wichmann spent his youth in Hamburg, where his father ran a boarding school. From 1871 to 1874 he studied at Leipzig University, where he was a pupil of Ferdinand Zirkel, from whom he got his interest in mineralogy. After he spent a few years as assistant to Zirkel he became professor at Utrecht University.
Geological research was never done at Utrecht before, and Wichmann committed himself to the task of starting a geological institute. Apart from setting up research and education Wichmann had to start a geological collection, for which reason he participated in expeditions to Dutch colonies, in 1888-1889 to the Dutch East Indies (Celebes, Flores, Timor and Rotti) and in 1902-1903 to New Guinea. As a scientist Wichmann was mainly interested in mineralogy and petrology. After his retirement in 1921 he returned to his city of birth Hamburg, where he died in 1927. His successor at Utrecht was L.M.R. Rutten.