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Sakmarian
In the geologic timescale, the Sakmarian is an age or stage of the Permian. 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 uses it as an independent stage in its international geologic timescale. The base of the Sakmarian Stage is laid with the first appearance of conodont species '' Streptognathodus postfusus'' in the fossil record. A global reference profile for the base (a GSSP), located in the southern Ural Mountains, Russia, was ratified in 2018. The top of the Sakmarian (t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sakmarian
In the geologic timescale, the Sakmarian is an age or stage of the Permian. 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 uses it as an independent stage in its international geologic timescale. The base of the Sakmarian Stage is laid with the first appearance of conodont species '' Streptognathodus postfusus'' in the fossil record. A global reference profile for the base (a GSSP), located in the southern Ural Mountains, Russia, was ratified in 2018. The top of the Sakmarian (t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian Geochronology
The Permian ( ) is a geologic period and 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 251.9 Mya. It is the 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 region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the 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 drier conditions, rose to dominance in place of their amphibian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian
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 251.9 Mya. It is the 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 drier conditi ... [...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] |
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 de ... [...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 from the Artinskian. At that moment 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 at the same time the base of the Cisuralian Series and the Permian System. It is defined as the place in the stratigraphic record where fossils of the conodont '' Streptognathodus isolatus'' fi ... [...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 (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 de ... [...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 de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artinskian
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 small Russian city of Arti (formerly ''Artinsk''), situated in the southern Ural mountains, about 200 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 as the first appearance datum (FAD) of the conodont species ''Sweetognathus whitei'' and '' Mesogondolella bisselli''. In order to constrain this age, the ICS subcommission on Permian stratigraphy informally proposed a candidate GSSP in 2002, later followed by a formal proposal in ... [...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. It has been found that recurrent parallel species pairs have occurred throughout ''Sweetognathus'' evolution between populations originating in Bolivia, the Mid-Western Unitied 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 Ura ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sakmara River
The Sakmara (russian: Сакмара; ba, Һаҡмар, 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 railway station Saraktash close to the Wozdwizhenskaya Fortress (Orenburg Oblast). It 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. [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
