Robert Hazen

Robert Miller Hazen (born November 1, 1948) is an American mineralogist and astrobiologist. He is a research scientist at the Carnegie Institution of Washington's Geophysical Laboratory and Clarence Robinson Professor of Earth Science at George Mason University, in the United States. Hazen is the Executive Director of the Deep Carbon Observatory.
Early life.
Hazen was born in Rockville Centre, New York, on November 1, 1948. His parents were Peggy Hazen ("née" Dorothy Ellen Chapin; 1918–2002) and Dan Hazen ("née" Daniel Francis Hazen, Jr.; 1918–2016). He spent his early childhood in Cleveland, near a fossil quarry where he collected his first trilobite at the age of about 9.
The Hazen family moved to New Jersey, where Robert's eight-grade teacher, Bill Welsh, observed Robert's interest in his collection of minerals. Hazen later recalled "He gave me a starter collection of 100 specimens, mineral field guides, and mimeographed directions to Paterson and Franklin, New Jersey." Hazen also had an early interest in music, starting with the piano at age 5, the violin at 6 and the trumpet at age 9.
Education.
Hazen worked on his B.S. and S.M. (Master of Science) in Earth Science at the Massachusetts Institute of Technology 1971. He started with the intention of going into chemical engineering, but he was captivated by the enthusiasm of David Wones and converted to mineralogy. With Wones as advisor, he completed a masters thesis on cation substitution in trioctahedral micas; his publication in "American Mineralogist" was his first to be highly cited. He completed a Ph.D. in Mineralogy & Crystallography at Harvard University in 1975. His thesis, with Charles Burnham as advisor, involved learning how to use a 4-circle diffractometer to do high-pressure X-ray crystallography and applying it to olivine. This became a focus of his early career.
While a NATO Postdoctoral Fellow at Cambridge University in England, Hazen worked with Charles Prewitt to determine empirical relations for the effect of temperature and pressure on interatomic distances in oxides and silicates.
Geophysical Laboratory.
In 1976, Hazen joined the Carnegie Institution's Geophysical Laboratory as a research associate. After a brief stint measuring optical properties of lunar minerals with Peter Bell and David Mao, he started to do X-ray crystallography with Larry Finger. He later recalled, "It was a match made in mineralogical heaven: Larry loved to write code, build machines, and analyze data; I loved to mount crystals, run the diffractometers, and write papers." They collaborated for two decades and determined about a thousand crystal structures at variable pressures and temperatures, work summarized in their 1982 book "Comparative Crystal Chemistry".
Much of the work that Hazen was doing could be classified as mineral physics, a cross between geophysics and mineralogy. Although the field had pioneering contributions from the Nobel Prize winner Percy Bridgman and a student of his, Francis Birch, in the early- to mid-20th century, it did not have a name until the 1960s, and in the 1970s some scientists were concerned that a more interdisciplinary approach was needed to understand the relationship between interatomic forces and mineral properties. Hazen and Prewitt co-convened the first mineral physics conference; it was held on October 17–19, 1977 at the Airlie House in Warrenton, Virginia.
High-temperature superconductors.
Cooled to very low temperatures, some materials experience a sudden transition where electrical resistance drops to zero and any magnetic fields are expelled. This phenomenon is called superconductivity. Superconductors have a host of applications including powerful electromagnets, fast digital circuits and sensitive magnetometers, but the very low temperatures needed make the applications more difficult and expensive. Until the 1980s, no superconductors existed above . Then in 1986 two IBM researchers, Georg Bednorz and K. Alex Müller, found a ceramic material with a critical temperature of . This set off a frenzied search for higher critical temperatures.
A group led by Paul Chu at the University of Houston explored some materials made of yttrium, barium, copper and oxygen (YCBO) and were the first to obtain a critical temperature above the boiling point of liquid nitrogen. The YCBO samples had a mixture of black and green minerals, and although the researchers knew the average composition, they did not know the compositions of the two phases. In February 1987, Chu turned to Mao and Hazen, because they could determine the composition of small mineral grains in rocks. It took Mao and Hazen a week to determine the compositions; the black phase, which turned out to be the superconductor, was YBa2Cu3O7-δ.
Mao and Hazen determined that the crystal structure of the superconducting phase was like that of perovskite, an important mineral in Earth's mantle. Subsequently, Hazen's group identified twelve more high-temperature oxide superconductors, all with perovskite structures, and worked on organic superconductors.
Origins of life.
By the mid-1990s, Hazen felt that his research had reached a "respectable plateau" where the main principles of how crystals compress were known. The questions he was asking were increasingly narrow and the answers rarely surprising. So he changed research directions to study life's chemical origins. This opportunity came when a colleague at George Mason University, Harold Morowitz, realized that the temperature and pressure at a hydrothermal vent might change the properties of water, allowing chemical reactions that ordinarily require the help of an enzyme. Enlisting the help of Hatten Yoder, a specialist in high pressure mineralogy, they tried subjecting pyruvate in water to high pressure, hoping for a simple reaction that would return oxaloacetate. Instead, an analysis by an organic geochemist, George Cody, found that they obtained tens of thousands of molecules.
The publication of their results, which seemed to support the deep sea vent hypothesis, met with heavy criticism, especially from Stanley Miller and colleagues who believe that life emerged on the surface. Along with the general criticism that organic compounds would not survive long in hot, high pressure conditions, they pointed out several flaws in the experiment. In his book, "Genesis", Hazen acknowledges that Stanley Miller "was basically right" about the experiments, but argues that "the art of science isn't necessarily to avoid mistakes; rather, progress is often made by making mistakes as fast as possible, while avoiding making the same mistake twice." In subsequent work, the group formed biomolecules from carbon dioxide and water and catalyzed the formation of amino acids using oxides and sulfides of transition metals; and different transition elements catalyze different organic reactions.
Homochirality.
Organic molecules often come in two mirror-image forms, often referred to as "right-handed" and "left-handed". This handedness is called chirality. For example, the amino acid alanine comes in a right-handed (D-alanine) and a left-handed (L-alanine) form. Living cells are very selective, choosing amino acids only in the left-handed form and sugars in the right-handed form. However, most abiotic processes produce an equal amount of each. Somehow life must have developed this preference (homochirality); but while scientists have proposed several theories, they have no consensus on the mechanism.
Hazen investigated the possibility that organic molecules might acquire a chiral asymmetry when grown on the faces of mineral crystals. Some, like quartz, come in mirror-image forms; others, like calcite, are symmetric about their centers but their faces come in pairs with opposite chirality. With Tim Filley, an expert at organic chemical analysis, and Glenn Goodfriend, a geochemist, Hazen cleaned large calcite crystals and dipped them into aspartic acid. They found that each face of the crystal had a small preference for either left- or right-handed forms of aspartate. They proposed that a similar mechanism might work on other amino acids and sugars. This work attracted a lot of interest from the pharmaceutical industry, which needs to produce some of their drugs with a pure chirality.
Mineral evolution.
At a Christmas party in 2006, the biophysicist Harold Morowitz asked Hazen whether there were clay minerals during the Archean Eon. Hazen could not recall a mineralogist ever having asked whether a given mineral existed in a given era, and it occurred to him that no one had ever explored how Earth's mineralogy changed over time. He worked on this question for a year with his closest colleague, geochemist Dimitri Sverjensky at Johns Hopkins University, and some other collaborators including a mineralogist, Robert Downs; a petrologist, John Ferry; and a geobiologist, Dominic Papineau. The result was a paper in "American Mineralogist" that provided a new historical context to mineralogy that they called mineral evolution.
Based on a review of the literature, Hazen and his co-authors estimated that the number of minerals in the Solar System has grown from about a dozen at the time of its formation to over 4300 at present. (As of 2017, the latter number has grown to 5300.). They predicted that there was a systematic increase in the number of mineral species over time, and identified three main eras of change: the formation of the Solar System and planets; the reworking of crust and mantle and the onset of plate tectonics; and the appearance of life. After the first era, there were 250 minerals; after the second, 1500. The remainder were made possible by the action of living organisms, particularly the addition of oxygen to the atmosphere. This paper was followed over the next few years by several studies concentrating on one chemical element at a time and mapping out the first appearances of minerals involving each element.
Deep Carbon Observatory.
Hazen and his colleagues started the Carbon Mineral Challenge, a citizen science project dedicated to accelerating the discovery of "missing" carbon-bearing minerals.
Teaching.
As the Clarence B. Robinson Professor at George Mason University, Hazen developed innovative courses to promote scientific literacy in both scientists and non-scientists. With physicist James Trefil, he developed a course that they described as "science appreciation", aimed at non-scientists. It was organized around a total of 20 "Great Ideas of Science" that were later reduced to 18. In addition to writing about their ideas in several magazines, they turned the course into a book, "Science Matters: Achieving Scientific Literacy." They used the principles to organize explanations of a "vast number of socially significant, fundamental, or environmentally crucial topics." This was published with an amount of advance publicity that was unusual for a popular science book, including an article they wrote for the "New York Times Sunday Magazine", praise from prolific author Isaac Asimov and physics Nobelist Leon Lederman, and a publicity tour. For an article in "Science" about the book, they provided the author with the original list of 20 ideas and invited readers to send in their comments. About 200 readers responded, generally supporting the idea of such a list while vehemently criticizing many of the particulars, including an informal style and sometimes vague language. Particularly criticized were numbers 1 ("The universe is regular and predictable") and 16 ("Everything on the earth operates in cycles"). Hazen and Trefil argued, in defense of point 1, that it was not intended as a defense of determinism and that they covered unpredictable phenomena like chaos; but they also used the responses to modify the list of ideas in subsequent editions.
Hazen and Trefil went on to write three undergraduate textbooks: "The Sciences: An Integrated Approach" (1993), "The Physical Sciences: An Integrated Approach" (1995), and "Physics Matters: An Introduction to Conceptual Physics" (2004). Hazen used these as the basis for a 60-lecture video and audio course called "The Joy of Science".
Public engagement.
In 2008, Hazen was an outgoing member of the AAAS Committee on Public Understanding of Science and Technology. He and his wife Margee, noting that it is important for scientists to engage with the public but actually doing so does not help them get tenure, proposed a new award, The Early Career Award for Public Engagement with Science, and established a fund for it. The first award, with a monetary prize of $5,000, was announced in 2010.
Honors.
Hazen is a Fellow of the American Association for the Advancement of Science.
The Mineralogical Society of America presented Hazen with the Mineralogical Society of America Award in 1982 and the Distinguished Public Service Medal in 2009. In 2016, he received its highest award, the Roebling Medal. He also served as Distinguished Lecturer and is a Past President of the Society. A mineral that was discovered in Mono Lake was named hazenite in his honor by Hexiong Yang, a former student of his.
In 1986, Hazen received the Ipatieff Prize, which the American Chemical Society awards in recognition of "outstanding chemical experimental work in the field of catalysis or high pressure".
For the book "The Music Men", he and his wife Margaret received the Deems Taylor Award from the American Society of Composers, Authors and Publishers in 1989.
For his popular and educational science writing, Hazen received the E.A. Wood Science Writing Award from the American Crystallographic Association in 1998,
In 2012, the State Council of Higher Education for Virginia presented Hazen with its Outstanding Faculty Award.
Hazen has presented numerous named lectures at universities. He gave a Directorate for Biological Sciences Distinguished Lecture at the National Science Foundation in 2007, and was named the Sigma Xi Distinguished Lecturer for 2008–2010.
In 2019, Hazen was named a Fellow of the American Geophysical Union.
Publications.
Hazen is author of more than 350 articles and 20 books on science, history, and music.
Refereed articles.
Hazen has 289 refereed publications that have been cited a total of over 11,000 times, for an h-index of 58. A selection of articles follows:
Family.
Hazen's wife, Margee "(née" Margaret Joan Hindle), is a science writer and published historian. Her late father, Howard Brooke Hindle, PhD (1918–2001), was a historian who studied the role of material culture in the history of the United States and served as Director of the National Museum of American History from 1974 to 1978. Hazen's late brother, Dan Chapin Hazen, PhD (1947–2015), was an academic research librarian who had been affiliated with the libraries at Harvard, and was particularly recognized for his accomplishments to the Center for Research Libraries and advocacy of collections from Latin America. Harvard has memorialized Dan Hazen by establishing two chairs in his name.
The Hazens have two children: Benjamin Hindle Hazen (born 1976) and Elizabeth Brooke Hazen (born 1978).


Chloropagus Formation

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


Jon Blundy

Jonathan David Blundy FRS (born 7 August 1961) is Royal Society Research Professor at the School of Earth Sciences at the University of Oxford and honorary professor at the University of Bristol.
Education.
He is a graduate of University College, Oxford (B.A., 1983) and Trinity Hall, Cambridge, (PhD, 1989) and a former Kennedy Scholar at the Massachusetts Institute of Technology (1985). He was educated at St Paul's School, Brazil, Giggleswick School and Leeds Grammar School, where petrologists Keith Cox and Lawrence Wager also studied.
Career.
Blundy is most noted for advancing the understanding of how magmas are generated in the Earth's crust and mantle and of the processes that occur in volcanoes before they erupt. He undertook his PhD research at the University of Cambridge under the supervision of Professor Robert Stephen John Sparks on the granites of Adamello-Presanella in the Italian Alps. In series of seminal papers with Professor Bernard John Wood in the 1990s Blundy developed a theory of elastic strain to describe the uptake of trace elements into the crystal lattices of igneous minerals. The theory was based on high temperature and pressure experiments on molten rocks, and is now widely used to predict crystal-melt partition coefficients for use in modelling magmatic processes.
Blundy subsequently collaborated with Katharine Cashman at the University of Oregon on Mount St. Helens volcano in the Cascade Range of northwestern USA. Blundy and Cashman demonstrated the importance of degassing in driving the crystallisation of volatile-bearing magmas, a process that can occur without any attendant cooling. In fact, because of the release of latent heat of fusion, magmas that crystallise by decompression can actually get hotter in the process.
Awards and honours.
Blundy is a recipient of the F.W. Clarke Medal of the Geochemical Society (1997), and Murchison Fund (1998) and the Bigsby Medal of the Geological Society of London (2005). He was a Fulbright Scholar at University of Oregon in 1998, Guest Professor at Nagoya University in 2007 and elected as a Fellow of the Royal Society (FRS) in 2008. His nomination reads: Blundy was also awarded the Royal Society Wolfson Research Merit Award in 2011.


Odershausen Formation

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


McLish Formation

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


Neoprincipia

Neoprincipia is interpreted as the earliest crown-group red algae.


Moctezuma, Sonora

Moctezuma is a "municipio" (municipality) of the Mexican state of Sonora, located in the state's central region. It is also the name of its largest settlement and "cabecera municipal" (municipal seat).
Area and population.
The municipal area is 1,763.39 km2, with a population of 4,187 registered in 2000. The municipal seat had a population of 3,798 in 2000. It is located at an elevation of 677 meters.
Neighboring municipalities.
Neighboring municipalities are Cumpas in the north, Huásabas, Granados and Divisaderos in the east, Tepache, San Pedro de la Cueva Villa Pesqueira, and Baviácora in the west.
Road connections.
Moctezuma is 140 kilometers on Federal Highway 14 from Hermosillo passing through Ures, and Mazocahui. From Agua Prieta on Federal Highway 17 the distance is 204 km passing through Fronteras, Esqueda, and Nacozari. See maps at or .
History.
When the Spanish arrived the land was occupied by the Opata Indians. The settlement is believed to have been established by the Jesuit missionary Marcos del Río.
San Miguel Arcángel de Oposura, a large burnt brick church with vaulted ceiling, side bays, and an octagonal chapel with a wooden roof, was built by unidentified maestros brought to the site at great expense by Father Daniel Janusque sometime before his death in 1724. It continued under two of his successors until it was finished in February 1738.
The town was renamed Moctezuma in 1828, while before the name had been San Miguel Arcángel de Oposura, and later “Oposura”. Etymologically, Oposura means place of a lot of ironwood.
Geography.
The region is located in the river basin of the Río Moctezuma between two extensions of the Sierra Madre Occidental mountains. The climate is dry with an average annual temperature of 12.2°C.
Economic activity.
Agriculture and cattle raising are the main economic activities. Corn and beans are raised for subsistence while grasses (sorghum, alfalfa, ryegrass) are grown for cattle fodder. The cattle herd numbered 32,554 head in 2000 making cattle raising the main economic activity in the municipality.
The former gold-mine "La Bambolla" is located near Moctezuma, one of the most famous geological deposits of elementary tellurium and its minerals.


Herington Formation

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


Cosmorhaphe

Cosmorhaphe is an ichnogenus representing grazing feeding behavior (pascichnia).
The Renaissance naturalist Ulisse Aldrovandi discussed and described a specimen of "Cosmorhaphe", which is therefore among the first fossils to be illustrated


DuNoir Limestone

The DuNoir Limestone is a geologic formation in Wyoming. It preserves fossils dating back to the Cambrian period.


Labrador Group

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


Nohn Formation

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


Blaine Formation

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


Dalles Formation

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


Lithograph City Formation

The Lithograph City Formation is a geologic formation in Iowa, part of the Cedar Valley Group. It preserves fossils dating back to the Devonian period. The formation is composed of dolomite and limestone, with many fossils and vugs in the lower part, while the upper part contains few fossils.
The formation is named after exposures in the former company town of Lithograph City, where quarries were opened to exploit the high-quality lithographic limestone found in parts of this formation.


Karen McNally

Karen Cook McNally (1940 – December 20, 2014) was an American seismologist.
She was born in Clovis, California and received bachelor's (1971) and master's (1973) degrees and a PhD (1976) in geophysics from the University of California, Berkeley. McNally worked at the California Institute of Technology with Charles Francis Richter, creator of the Richter magnitude scale, and became part of the faculty at the University of California, Santa Cruz in 1981. She was director of the Richter Seismological Laboratory there and their instruments were able to capture high-quality recordings of the 1989 Loma Prieta earthquake. She founded the Institute of Tectonics and helped establish a seismology research program at the University.
McNally established a modern geophysical observatory and a national seismographic network in Costa Rica, and was able to improve that country's program for reducing earthquake hazards. She was awarded a medal by the National University of Costa Rica for her efforts.
She was a member of the board of directors for the Seismological Society of America and the Incorporated Research Institutions for Seismology and sat on the California Earthquake Prediction Evaluation Council. In 1982, she received the Richtmyer Memorial Award from the American Association of Physics Teachers.
She married at a young age and had two daughters; the couple divorced in 1966. She died at home in Davenport at the age of 74.


Precambrian

The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the Latinised name for Wales, where rocks from this age were first studied. The Precambrian accounts for 88% of the Earth's geologic time.
The Precambrian (colored red in the timeline figure) is an informal unit of geologic time, subdivided into three eons (Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.6 billion years ago (Ga) to the beginning of the Cambrian Period, about million years ago (Ma), when hard-shelled creatures first appeared in abundance.
Overview.
Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earth's history, and what is known has largely been discovered from the 1960s onwards. The Precambrian fossil record is poorer than that of the succeeding Phanerozoic, and fossils from the Precambrian (e.g. stromatolites) are of limited biostratigraphic use. This is because many Precambrian rocks have been heavily metamorphosed, obscuring their origins, while others have been destroyed by erosion, or remain deeply buried beneath Phanerozoic strata.
It is thought that the Earth coalesced from material in orbit around the Sun at roughly 4,543 Ma, and may have been struck by another planet called Theia shortly after it formed, splitting off material that formed the Moon (see Giant impact hypothesis). A stable crust was apparently in place by 4,433 Ma, since zircon crystals from Western Australia have been dated at 4,404 ± 8 Ma.
The term "Precambrian" is used by geologists and paleontologists for general discussions not requiring a more specific eon name. However, both the United States Geological Survey and the International Commission on Stratigraphy regard the term as informal. Because the span of time falling under the Precambrian consists of three eons (the Hadean, the Archean, and the Proterozoic), it is sometimes described as a "supereon", but this is also an informal term, not defined by the ICS in its chronostratigraphic guide.
 (from “earliest”) was a synonym for "pre-Cambrian", or more specifically "Archean".
Life forms.
A specific date for the origin of life has not been determined. Carbon found in 3.8 billion-year-old rocks (Archean eon) from islands off western Greenland may be of organic origin. Well-preserved microscopic fossils of bacteria older than 3.46 billion years have been found in Western Australia. Probable fossils 100 million years older have been found in the same area. However, there is evidence that life could have evolved over 4.280 billion years ago. There is a fairly solid record of bacterial life throughout the remainder (Proterozoic eon) of the Precambrian.
Complex multicellular organisms may have appeared as early as 2100 Ma. However, the interpretation of ancient fossils is problematic, and "... some definitions of multicellularity encompass everything from simple bacterial colonies to badgers." Other possible early complex multicellular organisms include a possible 2450 Ma red alga from the Kola Peninsula, 1650 Ma carbonaceous biosignatures in north China, the 1600 Ma "Rafatazmia", and a possible 1047 Ma "Bangiomorpha" red alga from the Canadian Arctic. The earliest fossils widely accepted as complex multicellular organisms date from the Ediacaran period. A very diverse collection of soft-bodied forms is found in a variety of locations worldwide and date to between 635 and 542 Ma. These are referred to as Ediacaran or Vendian biota. Hard-shelled creatures appeared toward the end of that time span, marking the beginning of the Phanerozoic eon. By the middle of the following Cambrian period, a very diverse fauna is recorded in the Burgess Shale, including some which may represent stem groups of modern taxa. The increase in diversity of lifeforms during the early Cambrian is called the Cambrian explosion of life.
While land seems to have been devoid of plants and animals, cyanobacteria and other microbes formed prokaryotic mats that covered terrestrial areas.
Tracks from an animal with leg-like appendages have been found in what was mud 551 million years ago.
Planetary environment and the oxygen catastrophe.
Evidence of the details of plate motions and other tectonic activity in the Precambrian has been poorly preserved. It is generally believed that small proto-continents existed prior to 4280 Ma, and that most of the Earth's landmasses collected into a single supercontinent around 1130 Ma. The supercontinent, known as Rodinia, broke up around 750 Ma. A number of glacial periods have been identified going as far back as the Huronian epoch, roughly 2400–2100 Ma. One of the best studied is the Sturtian-Varangian glaciation, around 850–635 Ma, which may have brought glacial conditions all the way to the equator, resulting in a "Snowball Earth".
The atmosphere of the early Earth is not well understood. Most geologists believe it was composed primarily of nitrogen, carbon dioxide, and other relatively inert gases, and was lacking in free oxygen. There is, however, evidence that an oxygen-rich atmosphere existed since the early Archean.
At present, it is still believed that molecular oxygen was not a significant fraction of Earth's atmosphere until after photosynthetic life forms evolved and began to produce it in large quantities as a byproduct of their metabolism. This radical shift from a chemically inert to an oxidizing atmosphere caused an ecological crisis, sometimes called the oxygen catastrophe. At first, oxygen would have quickly combined with other elements in Earth's crust, primarily iron, removing it from the atmosphere. After the supply of oxidizable surfaces ran out, oxygen would have begun to accumulate in the atmosphere, and the modern high-oxygen atmosphere would have developed. Evidence for this lies in older rocks that contain massive banded iron formations that were laid down as iron oxides.
Subdivisions.
A terminology has evolved covering the early years of the Earth's existence, as radiometric dating has allowed absolute dates to be assigned to specific formations and features. The Precambrian is divided into three eons: the Hadean (– Ma), Archean (- Ma) and Proterozoic (- Ma). See Timetable of the Precambrian.
It has been proposed that the Precambrian should be divided into eons and eras that reflect stages of planetary evolution, rather than the current scheme based upon numerical ages. Such a system could rely on events in the stratigraphic record and be demarcated by GSSPs. The Precambrian could be divided into five "natural" eons, characterized as follows:
Precambrian supercontinents.
The movement of Earth's plates has caused the formation and break-up of continents over time, including occasional formation of a supercontinent containing most or all of the landmass. The earliest known supercontinent was Vaalbara. It formed from proto-continents and was a supercontinent 3.636 billion years ago. Vaalbara broke up c. 2.845–2.803 Ga ago. The supercontinent Kenorland was formed c. 2.72 Ga ago and then broke sometime after 2.45–2.1 Ga into the proto-continent cratons called Laurentia, Baltica, Yilgarn craton and Kalahari. The supercontinent Columbia, or Nuna, formed 2.1–1.8 billion years ago and broke up about 1.3–1.2 billion years ago. The supercontinent Rodinia is thought to have formed about 1300-900 Ma, to have embodied most or all of Earth's continents and to have broken up into eight continents around 750–600 million years ago.


Conglomerat de Pierrefitte

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


Volcanic passive margin

Volcanic passive margins (VPM) and non-volcanic passive margins are the two forms of transitional crust that lie beneath passive continental margins that occur on Earth as the result of the formation of ocean basins via continental rifting. Initiation of igneous processes associated with volcanic passive margins occurs before and/or during the rifting process depending on the cause of rifting. There are two accepted models for VPM formation: hotspots/mantle plumes and slab pull. Both result in large, quick lava flows over a relatively short period of geologic time (i.e. a couple of million years). VPM's progress further as cooling and subsidence begins as the margins give way to formation of normal oceanic crust from the widening rifts.
Characteristics.
Despite the differences in origin and formation, most VPMs share the same characteristics:
Development.
Rift initiation.
Active rifting.
The active rift model sees rupture driven by hotspot or mantle plume activity. Upwellings of hot mantle, known as mantle plumes, originate deep in Earth and rise to heat and thin the lithosphere. Heated lithosphere thins, weakens, rises, and finally rifts, Enhanced melting following continental breakup is very important in VPMs, creating thicker than normal oceanic crust of 20 to 40 km thick. Other melts caused by convection related upwelling form reservoirs of magma from which dike swarms and sills eventually radiate to the surface, creating the characteristic seaward dipping lava flows. This model is controversial.
Passive rifting.
The passive rift model infers that slab pull stretches the lithosphere and thins it. To compensate for lithospheric thinning, asthenosphere upwells, melts due to adiabatic decompression, and derivative melts rise to the surface to erupt. Melts push up through faults towards the surface, forming dikes and sills.
Development of transitional crust.
Continued extension leads to accelerated igneous activity, including repeated eruptions. Repeated eruptions form a thick sequence of lava beds that can reach a combined thickness of up to 20 km. These beds are identified on seismic refraction sections as seaward dipping reflectors. It is important to note that the early phase of volcanic activity is not limited to the production of basalts. Rhyolite and other felsic rocks can also be found in these zones.
Continued extension with volcanic activity forms transitional crust, welding ruptured continent to nascent ocean floor. Volcanic beds cover the transition from thinned continental crust to oceanic crust. Also occurring during this phase is the formation of high velocity seismic zones under the thinned continental crust and the transition crust. These zones are identified by typical seismic velocities between 7.2-7.7 km/s and are usually interpreted as layers of mafic to ultramafic rocks that have underplated the transitional crust.
Asthenospheric upwelling leads to the formation of a mid-ocean ridge and new oceanic crust progressively separates the once-conjoined rift halves. Continued volcanic eruptions spread lava flows across transitional crust and onto oceanic crust. Due to the high rate of magmatic activity the new oceanic crust forms much thicker than typical oceanic crust. An example of this is Iceland where oceanic crust has been identified as being up to 40 km thick. Some have theorized that the copious amounts of volcanic material also lead to the formation of oceanic plateaus at this time.
Post-rift.
The final and longest phase is the continued thermal subsidence of the transitional crust and the accumulation of sediments. Continued seafloor spreading leads to the formation of oceanic crust of normal thickness. Over time this production of normal oceanic crust and sea floor spreading leads to the formation of an ocean. This phase is of the most interest to the oil industry and sedimentary geologists.
Distribution and examples.
The distribution of known volcanic margins is shown on the graphic to the right. Many of the margins have not been thoroughly investigated and more passive margins are identified as volcanic from time to time.
Volcanic passive margins:
VPM example: The US Atlantic Margin.
The US Atlantic passive margin extends from Florida to southern Nova Scotia. This VPM was a result of the breakup of the supercontinent, Pangea, in which North America separated from northwestern Africa and Iberia to form the North Atlantic Ocean. This margin has a typical history of tectonic events that are representative of volcanic passive margins with rifting and passive margin formation occurring 225-165 million years ago. Like other VPMs the US East Coast Margin developed in two stages; 1) rifting, initiated during the Middle to Late Triassic and continued into Jurassic time and 2) seafloor spreading, which began in Jurassic time and continues today. The US East Coast includes several components which are characteristic of VPM's including; seaward-dipping reflectors, flood basalts, dikes, and sills.


Mount Ferguson (Ontario)

Mount Ferguson, sometimes called Ferguson Mountain, is a mountain in the Municipality of Temagami, Northeastern Ontario, Canada. It overlooks Ferguson Bay of Lake Temagami with an elevation of above sea level, making it one of the highest mountains in the area. Mount Ferguson is situated near the boundary of geographic townships Cynthia and Aston.
The mountain is named after Peter A. Ferguson, a gold prospector from the town of Mattawa who staked mining claims on Mount Ferguson in the 1880s. He is also the namesake for Ferguson Bay, Ferguson Island and Ferguson Point. A fire lookout tower set up by the Department of Lands and Forests (now the Ministry of Natural Resources and Forestry) had formerly occupied the summit of Mount Ferguson. In 1966, the tower was no longer used which led to its eventual demolition around 1975.
Like the other highest peaks of this area, Mount Ferguson is underlain by Nipissing diabase. This forms a 2.2 billion year old magmatic province with an east–west extent of almost and a north–south extent of up to .


Advance Formation

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


Jefferson City Formation

The Jefferson City Formation or Jefferson City Dolomite is a geologic formation in the Ozarks of Missouri and Arkansas. The Jefferson City is in part not differentiated from the Cotter Formation of northern Arkansas. It preserves fossils dating back to the Ordovician period.


Hector Formation

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


Section restoration

In structural geology section restoration or palinspastic restoration is a technique used to progressively undeform a geological section in an attempt to validate the interpretation used to build the section. It is also used to provide insights into the geometry of earlier stages of the geological development of an area. A section that can be successfully undeformed to a geologically reasonable geometry, without change in area, is known as a "balanced section".
Comparably a palinspastic map is a map view of geological features, often also including present-day coastlines to aid the reader in recognising the area, representing the state before deformation.
2D restoration.
Development of technique.
The earliest attempts to produce restored sections were on foreland fold and thrust belts. This technique assumed a stratigraphic template with unit thicknesses either constant or smoothly varying across the section. Line lengths were measured on the present-day deformed section and transferred to the template, to rebuild the section as it was before deformation started. This method does not guarantee that area is conserved, only line length. The technique was applied to areas of extensional tectonics initially using vertical simple shear. Over the next decade several types of commercial restoration software became available, allowing the technique to be routinely applied.
Deformation algorithms.
In order to calculate the change in shape of an element within the section, various deformation algorithms are used. Initially many of these were applied manually, but are now available in specialist software packages. It is worth mentioning that these deformation algorithms are approximations and idealizations of actual strain paths and deviate from reality (Ramsey and Huber, 1987). Geologic media are typically not continuum materials; that is, they are not isotropic media as is implicitly assumed in all strain algorithms used for cross-section balancing. That said, balanced cross sections maintain material balance, which is important for conceptualizing kinematic histories of deformed regions.
Vertical/inclined shear.
This mechanism deforms an element to accommodate a change in shape by movement on closely spaced parallel planes of slip. The commonest assumption is vertical shear although comparisons with well understood examples suggest that antithetic inclined shear (i.e. in the opposite sense of dip to the controlling fault) at about 60°–70° is the best approximation to the behaviour of real rocks under extension. These algorithms preserve area but do not, in general, preserve line length. Restoration using this type of algorithm can be carried out by hand, but is normally done using specialist software. This algorithm is not generally thought to represent the actual mechanism by which deformation occurs, just to represent a reasonable approximation.
Flexural slip.
In a flexural slip algorithm deformation occurs by unfolding the deformed fault bounded horse by slip along bedding planes. This modelling mechanism does represent a real geological mechanism, as shown by slickensides along folded bedding planes. The shape of the unfolded horse is further constrained either by using the restored fault boundary to the previous horse in the restored section of by using an internal pin within the block itself, assuming this was unsheared during the deformation. This algorithm is normally only used in software based restoration. It preserves both area and line length.
Trishear.
A trishear algorithm is used to model and restore fault-propagation folds as other algorithms fail to explain thickness changes and strain variations associate with such folds. The deformation within the tip-zone of the propagating fault is idealised to heterogeneous shear within a triangular zone starting at the fault tip.
Compaction.
In most section restorations there is an element of backstripping and decompaction. This is necessary to adjust the geometry of the section for the compactional effects of later sediment loading.
Forward modelling.
Section restoration involves undeforming a natural example, a form of inverse modelling. In many cases carrying out forward modelling helps to test out concepts for all or part of the section.
3D restoration.
A basic assumption of 2D restoration is that the displacement on all faults is within the plane of the section. It also assumes that no material enters or leaves the section plane. In areas of complex multi-phase or strike slip deformation or where salt is present, this is rarely the case. 3D restoration can only be carried out using specialist software, such as Midland Valley's Move3D, Paradigm's Kine3D or Schlumberger's Dynel3D. The results of such restoration can be used to study the migration of hydrocarbons at an earlier stage.


Chaffin Formation

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


Balclatchie Formation

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


Chee Tor Limestone

The Chee Tor Limestone is a geologic formation in England. It preserves fossils dating back to the Carboniferous period.


Joint (geology)

A joint is a break (fracture) of natural origin in the continuity of either a layer or body of rock that lacks any visible or measurable movement parallel to the surface (plane) of the fracture ("Mode 1" Fracture). Although they can occur singly, they most frequently occur as joint sets and systems. A "joint set" is a family of parallel, evenly spaced joints that can be identified through mapping and analysis of the orientations, spacing, and physical properties. A "joint system" consists of two or more intersecting joint sets.
The distinction between joints and faults hinges on the terms "visible" or "measurable," a difference that depends on the scale of observation. Faults differ from joints in that they exhibit visible or measurable lateral movement between the opposite surfaces of the fracture ("Mode 2" and "Mode 3" Fractures). As a result, a joint may have been created by either strict movement of a rock layer or body perpendicular to the fracture or by varying degrees of lateral displacement parallel to the surface (plane) of the fracture that remains “invisible” at the scale of observation.
Joints are among the most universal geologic structures as they are found in most every exposure of rock. They vary greatly in appearance, dimensions, and arrangement, and occur in quite different tectonic environments. Often, the specific origin of the stresses that created certain joints and associated joint sets can be quite ambiguous, unclear, and sometimes controversial. The most prominent joints occur in the most well-consolidated, lithified, and highly competent rocks, such as sandstone, limestone, quartzite, and granite. Joints may be open fractures or filled by various materials. Joints infilled by precipitated minerals are called veins and joints filled by solidified magma are called dikes.
Formation.
Joints result from brittle fracture of a rock body or layer as the result of tensile stresses. These tensile stresses either were induced or imposed from outside, e.g. by the stretching of layers; the rise of pore fluid pressure as the result of either external compression or fluid injection; or the result of internal stresses induced by the shrinkage caused by the cooling or desiccation of a rock body or layer whose outside boundaries remained fixed.
When tensional stresses stretch a body or layer of rock such that its tensile strength is exceeded, it breaks. When this happens the rock fractures in a plane parallel to the maximum principal stress and perpendicular to the minimum principal stress (the direction in which the rock is being stretched). This leads to the development of a single sub-parallel joint set. Continued deformation may lead to development of one or more additional joint sets. The presence of the first set strongly affects the stress orientation in the rock layer, often causing subsequent sets to form at a high angle, often 90°, to the first set.
Types of joints.
Joints are classified either by the processes responsible for their formation or their geometry.
Classification of joints by geometry.
The geometry of joints refers to the orientation of joints as either plotted on stereonets and rose-diagrams or observed in rock exposures. In terms of geometry, three major types of joints, nonsystematic joints, systematic joints, and columnar jointing are recognized.
Nonsystematic joints.
"Nonsystematic joints" are joints that are so irregular in form, spacing, and orientation that they cannot be readily grouped into distinctive, through-going joint sets.
Systematic joints.
"Systematic joints" are planar, parallel, joints that can be traced for some distance, and occur at regularly, evenly spaced distances on the order centimeters, meters, tens of meters, or even hundreds of meters. As a result, they occur as families of joints that form recognizable joint sets. Typically, exposures or outcrops within a given area or region of study contains two or more sets of systematic joints, each with its own distinctive properties such as orientation and spacing, that intersect to form well-defined joint systems.
Based upon the angle at which joint sets of systematic joints intersect to form a joint system, systematic joints can be subdivided into conjugate and orthogonal joint sets. The angles at which joint sets within a joint system commonly intersect is called by structural geologists as the "dihedral angles." When the dihedral angles are nearly 90° within a joint system, the joint sets are known as "orthogonal joint sets". When the dihedral angles are from 30 to 60° within a joint system, the joint sets are known as "conjugate joint sets".
Within regions that have experienced tectonic deformation, systematic joints are typically associated with either layered or bedded strata that has been folded into anticlines and synclines. Such joints can be classified according to their orientation in respect to the axial planes of the folds as they often commonly form in a predictable pattern with respect to the hinge trends of folded strata. Based upon their orientation to the axial planes and axes of folds, the types of systematic joints are:
Columnar jointing.
"Columnar jointing" is a distinctive type of joints that join together at triple junctions either at or about 120° angles. These joints split a rock body into long, prisms or columns. Typically, such columns are hexagonal, although 3-, 4-, 5- and 7-sided columns are relatively common. The diameter of these prismatic columns range from a few centimeters to several metres. They are often oriented perpendicular to either the upper surface and base of lava flows and the contact of the tabular igneous bodies with the surrounding rock. This type of jointing is typical of thick lava flows and shallow dikes and sills. Columnar jointing is also known as either "columnar structure", "prismatic joints", or "prismatic jointing". Rare cases of columnar jointing have also been reported from sedimentary strata.
Types of joints with respect to formation.
Joints can also be classified according to their origin. On the basis of their origin, joints have been divided into a number of different types that include tectonic, hydraulic, exfoliation, unloading (release), and cooling joints depending on the specific author and publication. Also, the origin of many joint sets often can be unclear and quite ambiguous. Often, different authors have proposed multiple and contradictory hypotheses for specific joint sets and types. Finally, it should be kept in mind that different joints in the same outcrop may have formed at different times and for different reasons.
Tectonic joints.
"Tectonic joints" are joints that formed when the relative displacement of the joint walls is normal to its plane as the result of brittle deformation of bedrock in response to regional or local tectonic deformation of bedrock. Such joints form when directed tectonic stress causes the tensile strength of
bedrock to be exceeded as the result of the stretching of rock layers under conditions of elevated pore fluid pressure and directed tectonic stress. Tectonic joints often reflect local tectonic stresses associated with local folding and faulting. Tectonic joints occur as both nonsystematic and systematic joints, including orthogonal and conjugate joint sets.
Hydraulic joints.
"Hydraulic joints" are joints thought to have formed when pore fluid pressure became elevated as a result of vertical gravitational loading. In simple terms, the accumulation of either sediments, volcanic, or other material causes an increase in the pore pressure of groundwater and other fluids in the underlying rock when they cannot move either laterally of vertically in response to this pressure. This also causes an increase in pore pressure in preexisting cracks that increases the tensile stress on them perpendicular to the minimum principal stress (the direction in which the rock is being stretched). If the tensile stress exceeds the magnitude of the least principal compressive stress the rock will fail in a brittle manner and these cracks propagate in a process called hydraulic fracturing. Hydraulic joints occur as both nonsystematic and systematic joints, including orthogonal and conjugate joint sets. In some cases, joint sets can be a tectonic - hydraulic hybrid.
Exfoliation joints.
"Exfoliation joints" are sets of flat-lying, curved, and large joints that are restricted to massively exposed rock faces in an deeply eroded landscape. Exfoliation jointing consists of fan-shaped fractures varying from a few meters to tens of meters in size that lie sub-parallel to the topography. The vertical, gravitational load of the mass of a mountain-size bedrock mass drives longitudinal splitting and causes outward buckling toward the free air. In addition, paleostress sealed in the granite before the granite was exhumed by erosion and released by exhumation and canyon cutting is also a driving force for the actual spalling.
Unloading joints.
"Unloading joints" or "release joints" are joints formed near the surface during uplift and erosion. As bedded sedimentary rocks are brought closer to the surface during uplift and erosion, they cool, contract and become relaxed elastically. This causes stress buildup that eventually exceeds the tensile strength of the bedrock and results in the formation of jointing. In the case of unloading joints, compressive stress is released either along preexisting structural elements (such as cleavage) or perpendicular to the former direction of tectonic compression.
Cooling joints.
"Cooling joints" are columnar joints that result from the cooling of either lava from the exposed surface of a lava lake or flood basalt flow or the sides of a tabular igneous, typically basaltic, intrusion. They exhibit a pattern of joints that join together at triple junctions either at or about 120° angles. They split a rock body into long, prisms or columns that are typically hexagonal, although 3-, 4-, 5- and 7-sided columns are relatively common. They form as a result of a cooling front that moves from some surface, either the exposed surface of a lava lake or flood basalt flow or the sides of a tabular igneous intrusion into either lava of the lake or lava flow or magma of a dike or sill.
Fractography.
Joint propagation can be studied using the techniques of fractography in which characteristic marks such as hackles and plumose structures can be used to determine propagation directions and, in some cases, the principal stress orientations.
Shear fractures versus joints.
Some fractures that look like joints are actually shear fractures, which in effect are microfaults, instead of joints. Shear fractures do not form as the result of the perpendicular opening of a fracture due to tensile stress, but through the shearing of fractures that causes lateral movement of its faces. Shear fractures can be confused with joints, because the lateral offset of the fracture faces is not visible at the scale of outcrop or hand specimen. Because of the absence of diagnostic ornamentation or the lack of any discernible movement or offset, they can be indistinguishable from joints. Shear fractures occur in sets of planar parallel fractures at an angle of 60 degrees and can be of the same size and scale as joints. As a result, some "conjugate joint sets" may actually be shear fractures. In case of such "joint sets", it might be possible to distinguish joints from shear fractures by looking for the presence of slickensides, which are products of shearing movement parallel to the fracture surface. The slickensides are fine-scale, delicate ridge-in-groove lineations that are found on the surface of fracture surfaces.
Importance of joints.
Joints are important not only in understanding the local and regional geology and geomorphology, but also are important in development of natural resources, the safe design of structures, and environmental protection. Joints have a profound control on weathering and erosion of bedrock. As a result, they exert a strong control on how topography and morphology of landscapes develop. Understanding the local and regional distribution, physical character, and origin of joints is a significant part of understanding the geology and geomorphology of an area. Joints often impart a well-develop fracture-induced permeability to bedrock. As a result, joints strongly influence, even control, the natural circulation (hydrogeology) of fluids, e.g. groundwater and pollutants within aquifers, petroleum in reservoirs, and hydrothermal circulation at depth, within bedrock. Thus, joints are important to the economic and safe development of petroleum, hydrothermal, and groundwater resources and the subject of intensive research relative to the development of these resources. Also, regional and local joint systems exert a very strong control on how ore-forming (hydrothermal) fluids, consisting largely of , , and NaCl, that formed most of Earth's ore deposits circulated within the Earth crust. As a result, understanding their genesis, structure, chronology, and distribution is an important part of finding and profitably developing ore deposits of various types. Finally, joints often form discontinuities that may have a large influence on the mechanical behavior (strength, deformation, etc.) of soil and rock masses in, for example, tunnel, foundation, or slope construction. As a result, joints are an important part of geotechnical engineering in practice and research.


Stratum

In geology and related fields, a stratum (plural: strata) is a layer of sedimentary rock or soil, or igneous rock that was formed at the Earth's surface, with internally consistent characteristics that distinguish it from other layers. The "stratum" is the fundamental unit in a stratigraphic column and forms the basis of the study of stratigraphy. A stratum can be seen in almost every single country in the world.
Characteristics.
Each layer is generally one of a number of parallel layers that lie one upon another, laid down by natural processes. They may extend over hundreds of thousands of square kilometers of the Earth's surface. Strata are typically seen as bands of different colored or differently structured material exposed in cliffs, road cuts, quarries, and j river banks. Individual bands may vary in thickness from a few millimeters to a kilometer or more. A band may represent a specific mode of deposition: river silt, beach sand, coal swamp, sand dune, lava bed, etc.
Naming.
Geologists study rock strata and categorize them by the material of beds. Each distinct layer is typically assigned a name, usually based on a town, river, mountain, or region where the formation is exposed and available for study. For example, the Burgess Shale is a thick exposure of dark, occasionally fossiliferous, shale exposed high in the Canadian Rockies near Burgess Pass. Slight distinctions in material in a formation may be described as "members" (or sometimes "beds"). Formations are collected into "groups" while groups may be collected into "supergroups".


Bird Spring Formation

The Bird Spring Formation is a geologic formation in Nevada. It preserves fossils dating back to the Carboniferous and Permian periods.


Cathedral Peak (California)

Cathedral Peak is part of the Cathedral Range, a mountain range in the south-central portion of Yosemite National Park in eastern Mariposa and Tuolumne Counties. The range is an offshoot of the Sierra Nevada. The peak which lends its name to the range derives its name from its cathedral-shaped peak, which was formed by glacial activity: the peak remained uneroded above the glaciers in the Pleistocene.
Geography.
Cathedral Peak has a subsidiary summit to the west called Eichorn Pinnacle, for Jules Eichorn, who first ascended a class 5.4 route to its summit on July 24, 1931 with Glen Dawson.
In 1869, John Muir wrote in "My first summer in the Sierra":
Geology.
The Cathedral Peak Granodiorite of Cathedral Peak is an intrusion into an area of older intrusive (or plutonic) and metamorphic rock in the Sierra Nevada Batholith. It is part of a grouping of intrusions called the Tuolumne Intrusive Suite. Cathedral Peak is the youngest of the rock formations in the Suite, dating to the Cretaceous Period at 83 million years ago. Its composition is mainly granodiorite with phenocrysts of microcline.
Cathedral Peak was a nunatak during the Tioga glaciation of the last ice age, the peak projected above the glaciers, which carved and sharpened the peak's base while plucking away at its sides.


Clallam Formation

The Clallam Formation is a geologic formation in Washington (state). It preserves fossils dating back to the Neogene period.


Pentagon Formation

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


Lava pillars

Lava pillars are common within collapsed sheet flow terrain. Lava pillars are hollow inside forming a pipe-like channel between the bottom and the top of a lava flow. They sometimes coalesce to form walls or can be attached to other pillars by natural bridges.
Lava pillars originate as gaps between lava lobes as a lava flow initially advances. Water that is trapped beneath the flow is heated and channeled upward through these gaps. This cold water promotes rapid growth of the lava crust around the gaps. Then during flow inflation the hollow pillars continue to act as escape-routes for seawater trapped beneath the lava flow, and so the gaps between lobes grow upwards into pipe-like pillars. The height of the lava pillars is a measure of the maximum thickness the lava flow attained. After lava inflation ends and the eruption wanes, the molten interior of the sheet flow typically subsides leaving a series of "bathtub rings" along the sides of the pillars. These rings are formed as the crust on the subsiding lava repeatedly adheres to and then breaks off from the pillar's sides.
Lava pillars may continue to act as fluid conduits for years after an eruption. In uncollapsed lobate terrain, diffuse hydrothermal venting is typically focused in the depressions within the lobate lavas, which are probably underlain by pillars. Circ Vent is one example of this vent style, and is but one of dozens of similar vents within the same lobate terrain near the eastern edge of the 1998 flow. Lava pillars exposed within collapse areas are visible in the Rumble and Marker 33 areas.


Mid-Carboniferous unconformity

The Mid-Carboniferous unconformity is an unconformity located in many countries, such as England (Namurian Series), Thailand, The United States and more. It has been dated to the Namurian, Middle Carboniferous (c.326-313 Ma) and the formation is often noted as being similar to the mid-Carboniferous eustatic event.


TGT Oil and Gas Services

TGT Oilfield Services (TGT Oilfield Services) is an international oilfield service company specialising in production logging, hydrocarbon reservoir monitoring and geohydrodynamic modelling. The company is headquartered in Dubai (UAE) and has regional offices in more than fifteen countries including United States, Canada, Russia, Kazakhstan, Nigeria, Malaysia, Great Britain, Indonesia, Oman, Kuwait and Saudi Arabia. In Russia, TGT has its Technology Centre in Kazan and other offices in Usinsk and at the Skolkovo Technopark in Moscow.
Company history.
TGT Oil and Gas Services was founded in Kazan, Russia, in 1998 by A.M. Aslanyan and G.V. Vasilyev. Many of the specialists who formed the company were students of N.N. Neprimerov, Professor of Physics at Kazan State University, who created his school of oil reservoir studies and engineering in the 1950s.
In 2003, the company’s headquarters and main activities were relocated from Kazan to Dubai (UAE).
In 2011, TGT Oil and Gas Services underwent a financial and technical audit and joined the investment portfolio of Lime Rock Partners.
In 2011, TGT Oil and Gas Services initiated a proposal to the TatNeft petroleum company to form a joint venture for oil redevelopment and generated a redevelopment project for the Bavly oilfield of Tatarstan. The company proposed pilot tests to be conducted using innovative oil recovery technologies in one of the oil areas operated by TatNeft.
In 2014, the company presented its key technologies at the Open Innovations international forum.
In 2013, TGT Oil and Gas Services became an active member of the Smart City Kazan project and produced a plan to build an R & D Centre on an investment site in the project area. In 2013–2015, a research centre and a production park were to be built on an area of 5 ha to accommodate modern research laboratories, a hotel and production and storage facilities. The company also planned to participate in the creation of an educational cluster allowing students, graduates and young specialists to have practical training and study at the Park. In 2015, all the plans were implemented at another location in the same city.
As a result, the company built its own Technology Centre in 2015 in the Privolzhsky District of Kazan to accommodate 350 workplaces, with 100 of them in the company's manufacturing unit. The opening took place on 10 June 2015.
In 2016, President of the Republic of Tatarstan Rustam N. Minnikhanov paid a working visit to the Technology Centre.
in Russia, TGT Oil and Gas Services has several subsidiaries in the form of limited liability companies: TGT Prime, MIKS and others.
The company regularly participates in SPE's and other conferences, symposia and exhibitions held in New Orleans and Houston (USA) including CERA Week, organises the annual Winter School in Applied Modelling (WSAM) held in Dubai since 2006, organises and sponsors the annual SMIT Youth Scientific Conference on Mathematical Modelling and Information Technologies held in Kazan since 2009, and regularly participates in international exhibitions, workshops and symposia held in Moscow, Ufa, Abu Dhabi, Dubai, Jakarta and other locations.
Services and activities.
The company's key technologies have been developed in-house and patented in Russia and other countries, and its research and development activities are carried out as resident projects at the Skolkovo Innovation Centre in Moscow and at the IT Park in Kazan.
TGT Oil and Gas Services specialises in integrated well logging and provides the following solutions:
TGT Oil and Gas Services has developed the following technologies:


True polar wander on Mars

For some time, scientists have thought that the location of the poles of Mars shifted due to the great mass of volcanic material in the Tharsis dome which includes Olympus Mons, the highest volcano in the solar system. A study published in "Nature" supports this idea. For a period early in the history of Mars, the poles were about 20 degrees away from their present positions. At that time ice was deposited in a region called Dorsa Argentea Formation. Also, the Martian dichotomy was aligned along the equator. A band of rivers formed at around 25 degrees south carried water from the southern highlands to the northern lowlands. After the polar shift, the location of the dichotomy boundary and the band of river valleys shifted. Dorsa Argentea was no longer at the pole. To produce the change in the pole location, the tilt of the planet remained unchanged, rather the crust and mantle moved. They rotated around the core.
This study suggests that the volcanoes and the movement of the poles occurred at about the same time. Volcanoes were erupting when the rivers were flowing with water. Perhaps the volcanoes supplied much water to the atmosphere, as well as carbon dioxide to warm the atmosphere; these effects would provide water for the rivers.
Tharsis is found in the Amazonis quadrangle and the Tharsis quadrangle.


Greifensteine

The Greifensteine is a rock tower in the Ore Mountains, Germany, between the towns of Geyer, Ehrenfriedersdorf and Jahnsbach. The highest of the seven granite rocks reaches 731 m. Another six rock towers were demolished by quarrying, which ended in 1923.
Geology.
Geologically, the Greifensteine is the top of a pluton. During the Variscan orogeny, magma intruded along structural zones, but cooled and solidified before reaching the earth surface. When the Erzgebirge block raised, the resulting granite formation raised with it. The surrounding softer material eroded and the harder granite remained, creating the tors of the rock formation. The deposition of ores associated with the intrusion gave the area its name (Erzgebirge, literally "ore mountains").
Mineral finds.
Due to the productiveness of its ore deposits, the Greifensteine are also a well-known site of many different minerals and their varieties. As of 2014, a total of around 50 minerals and 10 varieties have been discovered here, including "inter alia" the well-known minerals andalusite, beryl, gypsum, haematite, muscovite, sphalerite, pyrite, topaz, wavellite and zircon, as well as various garnets, tourmalines, (dravite, elbaite, schorl) and wolframites. There are also rare minerals such as childrenite and natrodufrénite, as well as the radioactive minerals autunite and torbernite.
The Greifensteine is also a type locality for the following minerals: fluorapatite, greifensteinite, lacroixite and roscherite.
History.
The first indications of a settlement on the Greifensteine are from around 1180, and in 1349 the von Waldenburg family are seignory to the "Grifenstein" castle. The castle is documented in 1372 as "Slosz Cryfenstein". The castle was destroyed in the 14th century by fire, and was rebuilt afterwards. It was abandoned in the 15th century, the area was used as a quarry and all traces of the former castle are removed. Of the originally 13 rock towers, six have been demolished and used for their granite over the years. This activity was stopped in 1928, and the area has become a nature reserve.
Tourism.
Today, the Greifensteine is a nature reserve and a popular tourist attraction. The areal has a restaurant, a small museum and an outdoor theater that uses the rock towers as a dramatic backdrop. Stairs lead up to the tallest rock, which offers a nice view of the surrounding Erzgebirge. There are several rock climbing paths. In the surrounding area are the Greifenbachstauweiher and the Röhrgraben.
Stülpner-Höhle.
Karl Stülpner (1762–1842), a local renegade and folk hero (the "Robin Hood of the Erzgebirge") had a hiding place in one of the numerous caverns of the Greifensteine area. This "Stülpner-Höhle" (engl.: Stülpner's cavern) can still be visited today.


Shelter Island meteorite

Shelter Island meteorite was found on Mars by the "Opportunity" rover on October 1, 2009. It is about long.
History.
Shelter Island was the second of three iron meteorites encountered by the rover on Meridiani Planum within a few hundred meters, the others being Block Island and Mackinac Island.
Shelter Island may have fallen on Mars in the late Noachian period and is extensively weathered.


Afon Ffinnant Formation

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


Cowlitz Formation

The Cowlitz Formation is a geologic formation in Washington (state). It preserves fossils dating back to the Paleogene period
Findings.
The Cowlitz Formation holds fossils dating back to the Paleogene period. These fossils were discovered in 1911 through the work of Charles E. Weaver, Charles R. Fettkc, Donald Ross, T. A. Bonser, and Olaf Stromme in their task to study more closely the Tertiary Paleontology of Western Washington. Along with the Cowlitz Formation, they also closely observed the Tejon Formation. These two formations are a part of a greater Eocene of Western Washington. The basaltic lavas and tuffs occurring within the Eocene of western Washington have a thickness ranging from fifteen hundred to two thousand feet.
The Cowlitz Formation is located in the canyon of Olequa Creek between towns of Winlock and Olequa, in southwestern Lewis Co., and northwestern Cowlitz Co., WA.
The rocks composing this formation are sandstones, shales, conglomerates and subordinate amount of shaly limestone, together with numerous intercalated layers of tuff and basaltic lava. They arc partly marine and partly brackish water deposits.
A total Tertiary invertebrate marine fauna of forty five was discovered. Thirty of these were new and had been discovered for the first time. The Cowlitz Formation contained the following fauna:


Builth Volcanic

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


Mehrten Formation

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


Slot Burn Formation

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


Sutherland River Formation

The Sutherland River Formation is a geologic formation in Northwest Territories. It preserves fossils dating back to the Silurian period.


Caloosahatchee Formation

The Caloosahatchee Formation is a geologic formation in Florida. It preserves fossils dating back to the Pleistocene.


Tidal bundle

A tidal bundle is a sedimentary structure that forms in tidal areas as a result of spring and neap tides.
Overview.
A tidal bundle sequence can be seen as a variation in bed thickness with a periodicity of 14 days (diurnal) or 28 days (semidiurnal). During the neap tide, when the tidal current strength is weakest, smaller quantities of finer grains are deposited. As the tidal variation grows larger, towards the spring tide, larger quantities of coarser material will be deposited which results in an increasing bed thickness. Bed thickness will be greatest at the spring tide and then decreases as the tidal variation grows smaller, towards the neap tide again and the thinnest beds.
Significance.
The presence of tidal bundles depends on the presence of spring and neap tides, which can only occur in three-body gravitational systems (the Earth, the Sun and the Moon). Therefore, the earliest time from which tidal bundles can be identified gives a conclusive lower bound on the age of the Moon.


Sunil Kumar Singh (geochemist)

Sunil Kumar Singh (born 1971) is a leading Indian geochemist, a former professor at the Physical Research Laboratory and currently the director of the National Institute of Oceanography, India. He is known for his studies on low temperature elemental and isotope geochemistry and his researches are reported to have assisted in widening the understanding of the evolution of the Himalayas. His studies have been documented in several peer-reviewed articles; Google Scholar, an online repository of scientific articles, has listed 99 of them respectively.
Singh, born on 16 March 1971, is a former Scientific Steering Committee member and the incumbent member of the Data Management Committee of GEOTRACES, an international forum for research on the marine biogeochemical cycles of trace elements and isotopes. As a collaborator, he is associated with the "Ganga Corridor" program, an initiative of the Indian Institute of Technology, Kanpur and the Department of Science and Technology, India. He was the co-coordinator of "Weathering and Erosion" session of the 2016 Goldschmidt conference held in Yokohama. He is a recipient of the National Geoscience Award and an elected fellow of the Indian Academy of Sciences, the National Academy of Sciences, India , and the Indian National Science Academy. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards for his contributions to Earth, Atmosphere, Ocean and Planetary Sciences in 2016.


Gres du Glauzy

The Grès du Glauzy is a geologic formation in France. It preserves fossils dating back to the Ordovician period.


Robert S. Anderson

Robert Stewart Anderson (born November 17, 1952) is an American geomorphologist at the Institute of Arctic and Alpine Research.
Anderson graduated from Williams College in 1974 and pursued a master's and doctoral degree from Stanford University and the University of Washington, respectively. In 2006, Anderson was named a fellow of the American Geophysical Union. The University of Colorado Boulder honored Anderson with the Hazel Barnes Prize in 2014. The next year, he received the American Geophysical Union's G. K. Gilbert Award. In 2016, Anderson was appointed a CU Distinguished Professor.