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Early Ordovician
The Early Ordovician is the first epoch (geology), epoch of the Ordovician period, corresponding to the Lower Ordovician series (stratigraphy), series of the Ordovician system. It began after the Cambrian Stage 10, Age 10 of the Furongian epoch of the Cambrian and lasted from to million years ago, until the Dapingian age of the Middle Ordovician. It includes Tremadocian and Floian ages. History International Commission on Stratigraphy (ICS) appointed working groups on the boundaries of the Ordovician subdivisions in 1974. The boundaries were established by the fauna of conodonts and/or graptolites. In 1995, the Subcommission on Ordovician Stratigraphy, with the support of 90% majority of voting members, adopted the division of the Ordovician system into three series: Lower, Middle Ordovician, Middle and Upper Ordovician, Upper. In the same year, it was decided to divide each of the three series into two global stages. ''Tetragraptus approximatus'' zone was chosen as the base ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Commission On Stratigraphy
The International Commission on Stratigraphy (ICS), sometimes unofficially referred to as the International Stratigraphic Commission, is a daughter or major subcommittee grade scientific organization that concerns itself with stratigraphy, stratigraphical, geology, geological, and chronology, geochronological matters, worldwide. It is the largest subordinate body of the International Union of Geological Sciences (IUGS). The ICS is essentially a permanent working committee, working subcommittee, which meets far more regularly than the quadrennial meetings scheduled by the IUGS, when it meets as a congress or committee, membership of the whole. Aims One of its main aims, a project begun in 1974, is to establish a multidisciplinary standard and global geologic time scale that will ease paleontology, paleontological and geobiology, geobiological comparisons region to region by benchmarks with stringent and rigorous strata criteria called Global Boundary Stratotype Section and Points ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Furongian
The Furongian is the fourth and final epoch and series of the Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov .... It lasted from to million years ago. It succeeds the Miaolingian series of the Cambrian and precedes the Lower Ordovician Tremadocian Stage. It is subdivided into three stages: the Paibian, Jiangshanian and the unnamed Cambrian Stage 10, 10th stage of the Cambrian. History and naming The Furongian was also known as the Cambrian Series 4, and the name replaced the older term Upper Cambrian and equivalent to the local term Hunanian. The present name was ratified by the International Commission on Stratigraphy in 2003. () means 'lotus (genus), lotus' in Mandarin and refers to Hunan which is known as the "lotus state". Definition The lower boundary is defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Boundary Stratotype Section And Point
A Global Boundary Stratotype Section and Point (GSSP), sometimes referred to as a golden spike, 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 2024, 79 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 mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trofimuk Institute Of Petroleum-Gas Geology And Geophysics
Trofimuk Institute of Petroleum-Gas Geology and Geophysics of the Siberian Branch of the RAS, IPGG SB RAS () is a research institute in Novosibirsk, Russia. It was founded in 2005. History The Institute was formed in 2005 by merging the Institute of Geophysics SB RAS, Institute of Petroleum Geology SB RAS and Design and Technological Institute of Instruments for Geophysics and Ecology SB RAS. Activity The Institute has created two devices: ''EMS Nemfis'' and ''Geoviser'' which collected information about changes in the electrical resistivity of the study area. The instruments can detect disappeared ancient settlements. The equipment were tested in , a hillfort in Zdvinsky District of Novosibirsk Oblast Novosibirsk Oblast () is a federal subjects of Russia, federal subject of Russia (an oblast) located in southwestern Siberia. Its administrative center, administrative and economic center is the types of inhabited localities in Russia, city of N .... References {{Reflist Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologica Acta
''Geologica Acta'' is a peer-reviewed open-access scientific journal that covers research in the Earth sciences. It was established in 2003 as a successor to ''Acta Geológica Hispánica'' (1966-2002), a locally oriented journal published in Spanish. The journal is published by the University of Barcelona, the Instituto de Ciencias de la Tierra Jaume Almera ( CSIC), the Institut de Diagnosi Ambiental i Estudis de l'Aigua (CSIC), and the Autonomous University of Barcelona. Abstracting and indexing The journal is abstracted and indexed in: According to the ''Journal Citation Reports'', the journal has a 2017 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impact Factor of a journa ... of 0.692. References External links * Academic journals established in 2003 English-language journals Ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arenig
In geology, the Arenig (or Arenigian) is a time interval during the Ordovician period and also the suite of rocks which were deposited during this interval. History The term was first used by Adam Sedgwick in 1847 with reference to the "Arenig Ashes and Porphyries" in the neighbourhood of Arenig Fawr, in Merioneth, North Wales. The rock-succession in the Arenig district has been recognized by W. G. Fearnsides (“On the Geology of Arenig Fawr and Moel Llanfnant", Q.J.G.S. vol. lxi., 1905, pp. 608–640, with maps). The above succession is divisible into: # A lower series of gritty and calcareous sediments, the "Arenig Series" as it is now understood; # A middle series, mainly volcanic, with shale, the "Llandeilo Series"; and # The shale and limestones of the Bala or Caradoc Stage. It was to the middle series (2) that Sedgwick first applied the term "Arenig". In the typical region and in North Wales generally the Arenig series appears to be unconformable upon the Camb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Stratigraphic Chart
The International Commission on Stratigraphy (ICS), sometimes unofficially referred to as the International Stratigraphic Commission, is a daughter or major subcommittee grade scientific organization that concerns itself with stratigraphical, geological, and geochronological matters, worldwide. It is the largest subordinate body of the International Union of Geological Sciences (IUGS). The ICS is essentially a permanent working subcommittee, which meets far more regularly than the quadrennial meetings scheduled by the IUGS, when it meets as a congress or membership of the whole. Aims One of its main aims, a project begun in 1974, is to establish a multidisciplinary standard and global geologic time scale that will ease paleontological and geobiological comparisons region to region by benchmarks with stringent and rigorous strata criteria called Global Boundary Stratotype Section and Points (GSSPs) within the fossil record. (i.e. section of the rock record as of a core samp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Ordovician
The Late Ordovician is the third and final epoch of the Ordovician period, lasting million years and spanning from around 458.2 to 443.1 million years ago. The rocks associated with this epoch are referred to as the Upper Ordovician Series. At this time, Western and Central Europe and North America collided to form Laurentia, while glaciers built up in Gondwana, which was positioned over the South Pole. This caused a drop in global temperatures, resulting in "ice house" conditions. For most of this time, life continued to flourish, but at and near the end of the period, there were mass-extinction events that seriously affected planktonic forms like conodonts, graptolites, and some groups of trilobites (Agnostida and Pytchopariida, which completely died out, and the Asaphida which were much reduced). Brachiopods, bryozoans and echinoderms were also heavily affected, and the endocerid cephalopods died out completely, except for possible rare Silurian The Silurian ( ) is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graptolites
Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding organisms are known chiefly from fossils found from the Middle Cambrian (Miaolingian, Wuliuan) through the Lower Carboniferous ( Mississippian). A possible early graptolite, ''Chaunograptus'', is known from the Middle Cambrian. Recent analyses have favored the idea that the living pterobranch '' Rhabdopleura'' represents an extant graptolite which diverged from the rest of the group in the Cambrian. Fossil graptolites and ''Rhabdopleura'' share a colony structure of interconnected zooids housed in organic tubes (theca) which have a basic structure of stacked half-rings (fuselli). Most extinct graptolites belong to two major orders: the bush-like sessile Dendroidea and the planktonic, free-floating Graptoloidea. These orders most likely evolved from encrusting pterobranchs similar to ''Rhabdopleura''. Due to their widespread abundance, pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conodonts
Conodonts, are an extinct group of marine jawless vertebrates belonging to the Class (biology), class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning "cone", and ὀδούς (''odoús''), meaning "tooth"). They are primarily known from their hard, mineralised tooth-like structures called "conodont elements" that in life were present in the oral cavity and used to process food. Rare soft tissue remains suggest that they had elongate eel-like bodies with large eyes. Conodonts were a long-lasting group with over 300 million years of existence from the Cambrian (over 500 million years ago) to the beginning of the Jurassic (around 200 million years ago). Conodont elements are highly distinctive to particular species and are widely used in biostratigraphy as indicative of particular periods of geological time. Discovery and understanding of conodonts The teeth-like fossils of the conodont were first discovered by Heinz Christian Pander and the results published in Sain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floian
The Floian is the second stage of the Ordovician Period. It succeeds the Tremadocian with which it forms the Lower Ordovician series. It precedes the Dapingian Stage of the Middle Ordovician. The Floian extended from to million years ago. The lower boundary is defined as the first appearance of the graptolite species '' Tetragraptus approximatus''. History and naming The base of this stage was ratified by the International Commission on Stratigraphy (ICS) in 2002. The Floian Stage is named after Flo, a village in Västergötland, southern Sweden. The name "Floan" was proposed in 2004, but the ICS adapted Floian as the official name of the stage. GSSP The GSSP of the Floian is the lower Tøyen Shale in Diabasbrottet Quarry () which is an outcrop of a shale-dominated stratigraphic succession. The lower boundary of the Floian is defined as the first appearance of '' Tetragraptus approximatus'' which is about 2.1 above the Cambrian strata. Radiometric dating has set the Tremad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tremadocian
The Tremadocian is the lowest stage of Ordovician. Together with the later Floian Stage it forms the Lower Ordovician Epoch. The Tremadocian lasted from to million years ago. The base of the Tremadocian is defined as the First appearance datum, first appearance of the conodont species ''Iapetognathus fluctivagus'' at the Global Boundary Stratotype Section and Point (GSSP) section on Newfoundland (island), Newfoundland. Naming The Tremadocian is named after the village Tremadog, Tremadoc in Wales. The name was proposed by Adam Sedgwick in 1846 (as "Tremadoc group"). GSSP The GSSP for the beginning of the Tremadocian is the Green Point section () in Gros Morne National Park, in western Newfoundland (island), Newfoundland. It is defined as the First appearance datum, first appearance of the conodont species ''Iapetognathus fluctivagus''. This horizon can be found 101.8 m above the Greenpoint section datum within bed number 23. The boundary lies within the Broom Point Member, of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
