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Sakmarian
In the geologic timescale, the Sakmarian is an age or stage of the Permian period. It is a subdivision of the Cisuralian Epoch or Series. The Sakmarian lasted between 293.52 and million years ago (Ma). It was preceded by the Asselian and followed by the Artinskian.; 2004: ''A Geologic Time Scale 2004'', Cambridge University Press Stratigraphy The Sakmarian Stage is named after the Sakmara River in the Ural Mountains, a tributary to the Ural River. The stage was introduced into scientific literature by Alexander Karpinsky in 1874. In Russian stratigraphy, it originally formed a substage of the Artinskian Stage. Currently, the ICS (International Commission on Stratigraphy) uses it as an independent stage in its international geologic timescale. The base of the Sakmarian Stage is defined by the first appearance of conodont species '' Streptognathodus postfusus'' in the fossil record. A global reference profile for the stage's base (a GSSP A Global Boundary Stratotype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian Geochronology
The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the sixth and last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the Perm Governorate, region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the Sauropsida, sauropsids (reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptognathodus
''Streptognathodus'' is an extinct genus of conodonts from the Late Carboniferous to Early Permian. Use in stratigraphy Late Carboniferous The top of the Kasimovian stage is close to the first appearance of ''Streptognathodus zethus''. The golden spike for the Kasimovian stage has not yet been assigned (in 2008). The Kasimovian is subdivided into three conodont biozones: *'' Idiognathodus toretzianus'' Zone *''Idiognathodus sagittatus'' Zone *''Streptognathodus excelsus'' and ''Streptognathodus makhlinae'' Zone The base of the Gzhelian is at the first appearance of ''Streptognathodus zethus''. The top of the stage (also the top base of the Silesian and the base of the Permian system) is at the first appearance of ''Streptognathodus isolatus'' within the ''Streptognathus "wabaunsensis"'' chronocline. The Gzhelian stage is subdivided into five biozones, based on the conodont genus ''Streptognathodus'': * ''Streptognathodus wabaunsensis'' and ''Streptognathodus bellus'' ... [...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 (a 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 standardised international units of geological 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 precise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artinskian
In the geologic timescale, the Artinskian is an age (geology), age or stage (stratigraphy), stage of the Permian. It is a subdivision of the Cisuralian Epoch (geology), Epoch or series (stratigraphy), Series. The Artinskian likely lasted between and megaannum, million years ago (Ma) according to the most recent revision of the International Commission on Stratigraphy (ICS) in 2022. It was preceded by the Sakmarian and followed by the Kungurian. Stratigraphy The Artinskian is named after the goniatite grits of Artinsk which was introduced by Roderick Murchison, Édouard de Verneuil and count Alexander von Keyserling in their ''The Geology of Russia in Europe and the Ural Mountains'' (1845). The grits of Artinsk, in turn, get its name from the Artinsky District with center in the Russian smalltown of Arti, Russia, Arti (formerly ''Artinsk zavod''), situated in the middle Ural Mountains, Urals, about 170 km southwest of Yekaterinburg. The stage was introduced into scientific li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asselian
In the geologic timescale, the Asselian is the earliest geochronologic age or lowermost chronostratigraphic stage of the Permian. It is a subdivision of the Cisuralian Epoch or Series. The Asselian lasted between and million years ago (Ma). It was preceded by the Gzhelian (the latest or uppermost subdivision in the Carboniferous) and followed by the Sakmarian. Stratigraphy The Asselian Stage was introduced into scientific literature in 1954, when the Russian stratigrapher V.E. Ruzhenchev split it off from the Artinskian. At the time, the Artinskian still encompassed most of the lower Permian – its current definitions are more restricted. The Asselian is named after the Assel River in the southern Ural Mountains of Kazakhstan and Bashkortostan. The base of the Asselian Stage is equivalent to the base of the Cisuralian Series and the Permian System. It is defined as the point in the stratigraphic record where fossils of the conodont '' Streptognathodus isolatus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoch (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 (a 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 standardised international units of geological 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 precis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artinskian Stage
In the geologic timescale, the Artinskian is an age or stage of the Permian. It is a subdivision of the Cisuralian Epoch or Series. The Artinskian likely lasted between and million years ago (Ma) according to the most recent revision of the International Commission on Stratigraphy (ICS) in 2022. It was preceded by the Sakmarian and followed by the Kungurian. Stratigraphy The Artinskian is named after the goniatite grits of Artinsk which was introduced by Roderick Murchison, Édouard de Verneuil and count Alexander von Keyserling in their ''The Geology of Russia in Europe and the Ural Mountains'' (1845). The grits of Artinsk, in turn, get its name from the Artinsky District with center in the Russian smalltown of Arti (formerly ''Artinsk zavod''), situated in the middle Urals, about 170 km southwest of Yekaterinburg. The stage was introduced into scientific literature by Alexander Karpinsky in 1874. Base of the Artinskian The base of the Artinskian Stage is defined a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sweetognathus
''Sweetognathus'' is an extinct genus of conodonts in the family Sweetognathidae that evolved at the beginning of the Permian period (298.9 Ma), in near-equatorial, shallow-water seas. The genus is characterized by pustulose ornamentation on a wide, flat-topped carina. It originated in the earliest Permian as ''S. expansus'' from '' Diplognathodus edentulus''. ''Sweetognathus'' forms a species complex. The genus is named after paleontologist Walter C. Sweet. Recurrent parallel species pairs have occurred throughout ''Sweetognathus'' evolution between populations originating in Bolivia, the Midwestern United States, and Russia. Parallelisms have been found to occur in the denticle morphologies of their platform elements. Use in stratigraphy According to the List of Global Boundary Stratotype Sections and Points, the species ''Sweetognathus whitei'' made its first appearance during the Artinskian (some 290.1 ± 0.26 mya), in the Permian of the Ural Mountains The Ural M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sakmara River
The Sakmara (; , Haqmar) is a river in Russia that drains the southern tip of the Ural Mountains south into the river Ural. It is long, and has a drainage basin of . It is a right tributary of the Ural, which it meets in Orenburg. The source of the Sakmara is in the Republic of Bashkortostan. Other towns along the Sakmara are Yuldybayevo (Bashkortostan), Kuvandyk, and the railway station Saraktash close to the 18th-century Wozdwizhenskaya Fortress (Orenburg Oblast). The Sakmara rises in the southern Ural Mountains about west-southwest of Magnitogorsk and flows south through a valley with some canyon development. At Kuvandyk it swings west, leaves the mountains, and flows west parallel to the Ural River with many meanders for about (straight-line distance) before turning south to meet the Ural. Major tributaries are the Salmysh and the Bolshoy Ik, both from the north, with the latter joining the Sakmara near Saraktash. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
