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Bashkirian
The Bashkirian is in the ICS geologic timescale the lowest stage or oldest age of the Pennsylvanian. The Bashkirian age lasted from to Ma, is preceded by the Serpukhovian and is followed by the Moscovian. The Bashkirian overlaps with the upper part of the Namurian and lower part of the Westphalian stages from regional European stratigraphy. It also overlaps with the North American Morrowan and Atokan stages and the Chinese Luosuan and lower Huashibanian stages. Name and definition The Bashkirian was named after Bashkiria, the then Russian name of the republic of Bashkortostan in the southern Ural Mountains of Russia, home of the Bashkir people. The stage was introduced by Russian stratigrapher Sofia Semikhatova in 1934. The base of the Bashkirian is at the first appearance of conodont species ''Declinognathodus noduliferus''. The top of the stage (the base of the Moscovian) is at the first appearance of the conodonts ''Declinognathodus donetzianus'' or ''Idiognathoides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serpukhovian
The Serpukhovian is in the ICS geologic timescale the uppermost stage or youngest age of the Mississippian, the lower subsystem of the Carboniferous. The Serpukhovian age lasted from Ma to Ma. It is preceded by the Visean and is followed by the Bashkirian. The Serpukhovian correlates with the lower part of the Namurian Stage of European stratigraphy and the middle and upper parts of the Chesterian Stage of North American stratigraphy. Name and definition The Serpukhovian Stage was proposed in 1890 by Russian stratigrapher Sergei Nikitin and was introduced in the official stratigraphy of European Russia in 1974. It was named after the city of Serpukhov, near Moscow. The ICS later used the upper Russian subdivisions of the Carboniferous in its international geologic time scale. The base of the Serpukhovian is informally defined by the first appearance of the conodont '' Lochriea ziegleri'', though the utility and systematic stability of this species is not yet certain. N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvanian (geology)
The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, in the International Commission on Stratigraphy, ICS geologic timescale, the younger of two period (geology), subperiods (or upper of two system (stratigraphy), subsystems) of the Carboniferous Period. It lasted from roughly . As with most other geochronology, geochronologic units, the stratum, rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain by a few hundred thousand years. The Pennsylvanian is named after the U.S. state of Pennsylvania, where the coal-productive beds of this age are widespread. The division between Pennsylvanian and Mississippian (geology), Mississippian comes from North American stratigraphy. In North America, where the early Carboniferous beds are primarily marine limestones, the Pennsylvanian was in the past treated as a full-fledged geologic period between the Mississippian and the Permian. In parts of Europe, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Timescale
The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (scientific branch of geology that aims to determine the age of rocks). It is used primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardized international units of geologic time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective is to precisely define gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moscovian (Carboniferous)
The Moscovian is in the International Commission on Stratigraphy, ICS geologic timescale a stage (stratigraphy), stage or age (geology), age in the Pennsylvanian (geology), Pennsylvanian, the youngest system (stratigraphy), subsystem of the Carboniferous. The Moscovian age lasted from to Megaannum, Ma, is preceded by the Bashkirian and is followed by the Kasimovian. The Moscovian overlaps with the European regional Westphalian (stage), Westphalian stage and the North American Atokan and Desmoinesian stages. Name and definition The Moscovian Stage was introduced by Sergei Nikitin (geologist), Sergei Nikitin (1850 - 1909) in 1890, using brachiopods in the Moscow Basin of European Russia. Nikitin named the stage after Moscow, then a major city and now the capital of Russia. The base of the Moscovian is close to the first appearances of the conodonts ''Declinognathodus donetzianus'' and ''Idiognathoides postsulcatus'' or otherwise the fusulinid ''Aljutovella aljutovica''. Because th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Age (geology)
The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (scientific branch of geology that aims to determine the age of rocks). It is used primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardized international units of geologic time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective is to precisely define ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Declinognathodus
''Declinognathodus'' is an extinct genus of platform conodonts. Use in stratigraphy The Bashkirian, the oldest age of the Pennsylvanian (also known as Upper Carboniferous), contains six biozones based on conodont index fossils, two of which are named after ''Declinognathodus'' species: * the zone of ''Declinognathodus marginodosus'', * the zone of ''Declinognathodus noduliferus''. The GSSP point is at Arrow Canyon, Nevada, USA, with the first appearance of ''Declinognathodus noduliferus sensu lato''. The base of the Moscovian, the second stage in the Pennsylvanian, is close to the first appearances of the conodonts ''Declinognathodus donetzianus Nemirovskaya, 1990'' and '' Diplognathodus ellesmerensis Bender, 1980''. The Moscovian can biostratigraphically be divided into five conodont biozones, one of which is named after a ''Declinognathodus'' species : the zone of ''Declinognathodus donetzianus''. The GSSP candidate sections are the Ural mountains The Ural Mountain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bashkortostan
The Republic of Bashkortostan or Bashkortostan ( ba, Башҡортостан Республикаһы, Bashqortostan Respublikahy; russian: Республика Башкортостан, Respublika Bashkortostan),; russian: Респу́блика Башкортоста́н, r=Respublika Bashkortostan, p=rʲɪsˈpublʲɪkə bəʂkərtɐˈstan also unofficially called Bashkiria (russian: Башкирия, tr. Bashkiriya), is a republic of Russia located between the Volga and the Ural Mountains in Eastern Europe. It covers and has a population of 4 million. It is Russia's 7th most populous federal subject and most populous republic. Its capital and largest city is Ufa. Bashkortostan was established on .Национально-государственное устройство Башкортостана, 1917–1925 гг: Общее введение и Том 1 // Билал Хамитович Юлдашбаев, Китап, 2002, , 9785295029165Хрестоматия по и ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Idiognathoides
''Idiognathoides'' is an extinct genus of conodonts. Glen K. Merrill stated in 1963 that "conodont workers have considered ''Idiognathoides'' to be a junior synonym of '' Polygnathodella'' but it now proves to be a junior synonym of ''Cavusgnathus''. ''Polygnathodella'' and ''Cavusgnathus'' are shown to form a transitional series."Polygnathodella Harlton, 1933, or Idiognathoides Harris and Hollingsworth, 1933? Glen K. Merrill, Journal of Paleontology, March 1963, volume 37, issue 2abstract Use in stratigraphy The Bashkirian, the oldest age of the Pennsylvanian (also known as Upper Carboniferous), contains six biozones based on conodont index fossils, one of which contains an ''Idiognathoides'' species : the zone of ''Idiognathoides sinuatus''. The base of the Moscovian, the second stage in the Pennsylvanian, is close to the first appearances of the conodonts '' Declinognathodus donetzianus'' and ''Idiognathoides postsulcatus''. The GSSP candidate sections are the Ural moun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sofia Viktorovna Semikhartova
Sofia Viktorovna Semikhatova, (February 9, 1889 – October 28, 1973) was a Soviet geologist and paleontologist. She was a pioneer and developer in some of the most prominent petroleum-bearing regions of her country. Throughout a lengthy career in law studies and geological fields, Semikhatova published ninety works throughout Germany, England and the United States. She analyzed animal life development in the base Middle Carboniferous period. She separated the Bashkirian Stage into horizons. Although Semikhatova never taught in higher educational establishments (as wife and mother of three), she sacrificed much of her time and effort towards preparing young scientists for their future endeavours in geology. Early life She was born in St. Petersburg in 1889. Semikhatov began her education studying law in the highest course of the city. In 1913 she married Alexander Semikhatov and moved to Moscow, where she finished law school by correspondence. She resumed her education in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Westphalian (stage)
The Westphalian is a stage in the regional stratigraphy of northwest Europe with an age between roughly 313 and 304 Ma (million years ago). It is a subdivision of the Carboniferous system or period and the regional Silesian series. The Westphalian is named for the region of Westphalia (German: ''Westfalen'') in western Germany where strata of this age occur. The Coal Measures of England and Wales are also largely of Westphalian age though they also extend into the succeeding Stephanian. The Westphalian age is preceded by the Namurian stage/age (which corresponds to the Millstone Grit Series of Great Britain) and succeeded by the Stephanian stage/age (which corresponds to the uppermost part of the Coal Measures of Great Britain). In the official geologic timescale of the ICS, the Westphalian is placed within the Pennsylvanian epoch (318-299 Ma).F M Gradstein, J G Ogg, A G Smith et al 2004, ‘A Geologic Time Scale 2004’. The (regionally defined) Westphalian stage corres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Namurian
The Namurian is a stage in the regional stratigraphy of northwest Europe with an age between roughly 326 and 313 Ma (million years ago). It is a subdivision of the Carboniferous system or period and the regional Silesian series. The Namurian is named for the Belgian city and province of Namur where strata of this age occur (part of the Belgian Coal Measures). The Millstone Grit Group in the lithostratigraphy of northern England and parts of Wales is also of Namurian age. The Namurian age lasted from 326 to 313 million years ago. It is preceded by the Visean stage/age (which corresponds to the upper Carboniferous Limestone of Great Britain) and succeeded by the Westphalian stage/age (which corresponds to the lower and middle Coal Measures of Great Britain). In the official geologic timescale of the International Commission on Stratigraphy (ICS), the Namurian straddles the boundary between the Mississippian epoch (359-318 Ma) and the Pennsylvanian epoch (318-299 Ma). The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GSSP
A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. The effort to define GSSPs is conducted by the International Commission on Stratigraphy, a part of the International Union of Geological Sciences. Most, but not all, GSSPs are based on paleontological changes. Hence GSSPs are usually described in terms of transitions between different faunal stages, though far more faunal stages have been described than GSSPs. The GSSP definition effort commenced in 1977. As of 2022, 77 of the 101 stages that need a GSSP have a ratified GSSP. Rules A geologic section has to fulfill a set of criteria to be adapted as a GSSP by the ICS. The following list summarizes the criteria: * A GSSP has to define the lower boundary of a geologic stage. * The lower boundary has to be defined using a primary marker (usually first appearance datum of a fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
