|
Ruthven Bluff
Ruthven Bluff () is a large rock bluff 1 nautical mile (1.9 km) south of Sosa Bluff in the Schneider Hills portion of the Argentina Range, Pensacola Mountains. Mapped by United States Geological Survey (USGS) from surveys and U.S. Navy air photos, 1956–67. Named by Advisory Committee on Antarctic Names (US-ACAN) for Richard W. Ruthven, USGS surveyor who visited the bluff in the 1965–66 season. Geology Ruthven Bluff is an approximately high bluff of Cambrian limestone. This bluff exposes a thick archaeocyathid reef composed of massive boundstone. At this locality, the boundstone contains numerous irregular cavities that are in diameter. These cavities are lined with fibrous cement and filled with either ferroancalcite or internal sediment. At Ruthven Bluff, alternating beds of grainstone and burrowed packstone encase this reef. The packstone beds contain subparallel zones of calcite-filled burrow An Eastern chipmunk at the entrance of its burrow A burrow is a hol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sosa Bluff
The Argentina Range is a mountain range of rock peaks and bluffs, long, lying east of the northern part of Forrestal Range in the northeastern portion of the Pensacola Mountains of Antarctica. Discovered and photographed on January 13, 1956, in the course of a US Navy transcontinental nonstop plane flight from McMurdo Sound to Weddell Sea and return. Named by the Advisory Committee on Antarctic Names after Argentina, which for many years from 1955 maintained a scientific station on the Filchner Ice Shelf at the General Belgrano or Ellsworth Station site. The entire Pensacola Mountains were mapped by United States Geological Survey in 1967 and 1968 from ground surveys and from US Navy tricameral photographs taken in 1964. Features Geographical features include: Schneider Hills Panzarini Hills Other features * Blackwall Ice Stream * Recovery Glacier * San Martín Glacier * Support Force Glacier * Whichaway Nunataks Further reading * Gunter Faure, Teresa M. M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schneider Hills
The Argentina Range is a mountain range of rock peaks and bluffs, long, lying east of the northern part of Forrestal Range in the northeastern portion of the Pensacola Mountains of Antarctica. Discovered and photographed on January 13, 1956, in the course of a US Navy transcontinental nonstop plane flight from McMurdo Sound to Weddell Sea and return. Named by the Advisory Committee on Antarctic Names after Argentina, which for many years from 1955 maintained a scientific station on the Filchner Ice Shelf at the General Belgrano or Ellsworth Station site. The entire Pensacola Mountains were mapped by United States Geological Survey in 1967 and 1968 from ground surveys and from US Navy tricameral photographs taken in 1964. Features Geographical features include: Schneider Hills Panzarini Hills Other features * Blackwall Ice Stream * Recovery Glacier * San Martín Glacier * Support Force Glacier * Whichaway Nunataks Further reading * Gunter Faure, Teresa M. M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argentina Range
The Argentina Range is a mountain range of rock peaks and bluffs, long, lying east of the northern part of Forrestal Range in the northeastern portion of the Pensacola Mountains of Antarctica. Discovered and photographed on January 13, 1956, in the course of a US Navy transcontinental nonstop plane flight from McMurdo Sound to Weddell Sea and return. Named by the Advisory Committee on Antarctic Names after Argentina, which for many years from 1955 maintained a scientific station on the Filchner Ice Shelf at the General Belgrano or Ellsworth Station site. The entire Pensacola Mountains were mapped by United States Geological Survey in 1967 and 1968 from ground surveys and from US Navy tricameral photographs taken in 1964. Features Geographical features include: Schneider Hills Panzarini Hills Other features * Blackwall Ice Stream * Recovery Glacier * San Martín Glacier * Support Force Glacier * Whichaway Nunataks Further reading * Gunter Faure, Teresa M. Mensin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pensacola Mountains
The Pensacola Mountains are a large group of mountain ranges of the Transantarctic Mountains System, located in the Queen Elizabeth Land region of Antarctica. Geography They extend 450 km (280 mi) in a NE-SW direction. Subranges of the Pensacola Mountains include: Argentina Range, Forrestal Range, Dufek Massif, Cordiner Peaks, Neptune Range, Patuxent Range, Rambo Nunataks and Pecora Escarpment. These mountain units lie astride the extensive Foundation Ice Stream and Support Force Glacier which drain northward to the Ronne Ice Shelf. ;Naming Discovered and photographed on 13 January 1956 in the course of a transcontinental nonstop plane flight by personnel of United States Navy Operation Deep Freeze I from McMurdo Sound to Weddell Sea and return. Named by US-ACAN for the U.S. Naval Air Station, Pensacola, Florida, in commemoration of the historic role of that establishment in training aviators of the U.S. Navy. The mountains were mapped in detail by USGS from surveys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization's work spans the disciplines of biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. The agency was founded on March 3, 1879. The USGS is a bureau of the United States Department of the Interior; it is that department's sole scientific agency. The USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, and Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on the occasion of its hundredt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advisory Committee On Antarctic Names
The Advisory Committee on Antarctic Names (ACAN or US-ACAN) is an advisory committee of the United States Board on Geographic Names responsible for recommending commemorative names for features in Antarctica. History The committee was established in 1943 as the Special Committee on Antarctic Names (SCAN). It became the Advisory Committee on Antarctic Names in 1947. Fred G. Alberts was Secretary of the Committee from 1949 to 1980. By 1959, a structured nomenclature was reached, allowing for further exploration, structured mapping of the region and a unique naming system. A 1990 ACAN gazeeter of Antarctica listed 16,000 names. Description The United States does not recognise territorial boundaries within Antarctica, so ACAN assigns names to features anywhere within the continent, in consultation with other national nomenclature bodies where appropriate, as defined by the Antarctic Treaty System. The research and staff support for the ACAN is provided by the United States Geologi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian
The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period mya. Its subdivisions, and its base, are somewhat in flux. The period was established as "Cambrian series" by Adam Sedgwick, who named it after Cambria, the Latin name for 'Cymru' (Wales), where Britain's Cambrian rocks are best exposed. Sedgwick identified the layer as part of his task, along with Roderick Murchison, to subdivide the large "Transition Series", although the two geologists disagreed for a while on the appropriate categorization. The Cambrian is unique in its unusually high proportion of sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for limes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeocyathid
Archaeocyatha (or archaeocyathids 'ancient cups') is a taxon of extinct, sessile, reef-building marine sponges that lived in warm tropical and subtropical waters during the Cambrian Period. It is believed that the centre of the Archaeocyatha origin is now located in East Siberia, where they are first known from the beginning of the Tommotian Age of the Cambrian, 525 million years ago ( mya). In other regions of the world, they appeared much later, during the Atdabanian, and quickly diversified into over a hundred families. They became the planet's very first reef-building animals and are an index fossil for the Lower Cambrian worldwide. Preservation The remains of Archaeocyatha are mostly preserved as carbonate structures in a limestone matrix. This means that the fossils cannot be chemically or mechanically isolated, save for some specimens that have already eroded out of their matrices, and their morphology has to be determined from thin cuts of the stone in which the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reef
A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock outcrops, etc.—but there are also reefs such as the coral reefs of tropical waters formed by biotic processes dominated by corals and coralline algae, and artificial reefs such as shipwrecks and other anthropogenic underwater structures may occur intentionally or as the result of an accident, and sometimes have a designed role in enhancing the physical complexity of featureless sand bottoms, to attract a more diverse assemblage of organisms. Reefs are often quite near to the surface, but not all definitions require this. Earth's largest coral reef system is the Great Barrier Reef in Australia, at a length of over . Biotic There is a variety of biotic reef types, including oyster reefs and sponge reefs, but the most massive and widely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boundstone (rock)
A boundstone is a special type of carbonate rock in the Dunham classification Description In the original classification by Dunham(1962), boundstones are defined as "carbonate rocks showing signs of being bound during deposition [...]. The signs of binding are specific and occur within the sample being classified" In the modified Dunham classification by Embry and Klovan(1971), Boundstones in the sense of Dunham are subdivided into Bafflestones, Bindstones and Framestones. The term Boundstone "is retained for authochthonous limestones in which the specific mode of organic binding cannot be recognized" Lokier and Al Nunaibi(2016) define Boundstone as "an autochthonous carbonate-dominated rock in which there is any form of evidence that the original components were organically bound at the time of deposition; however, the mode of binding is not identifiable." In contrast to Embry and Klovan, they do not subdivide Boundstones into smaller classes. References {{Cite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grainstone
Under the Dunham classification (Dunham, 1962) system of limestones, a grainstone is defined as a grain-supported carbonate rock that contains less than 1% mud-grade material. This definition has recently been clarified as ''a carbonate-dominated rock that does not contain any carbonate mud and where less than 10% of the components are larger than 2 mm.'' The spaces between grains may be empty (pores) or filled by cement. The identification of grainstone The presence of any primary carbonate mud precludes a classification of grainstone. A study of the use of carbonate classification systems by Lokier and Al Junaibi (2016) highlighted that the most common source of confusion in the classification of grainstone was to misidentify fine-grained internal micrite, generated by in-situ processes, as clay–silt grade sediment - thus resulting in the misidentification of grainstone as packstone Under the Dunham classification (Dunham, 1962Dunham, R.J. (1962) Classification of carbonate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
