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Jiangshanian
The Jiangshanian is the middle stage of the Furongian series. It follows the Paibian Stage and is succeeded by the still unnamed Stage 10 of the Cambrian. The base is defined as the first appearance of the trilobite ''Agnostotes orientalis'' which is estimated to be million years ago. The Jiangshanian lasted until approximately million years ago. The Cambrian stage was named after Jiangshan, a city in China's Zhejiang province. The GSSP of the Jiangshanian is the "Duibian B Section" (), west of the village of Duibian(碓边), and 10 km north of Jiangshan Jiangshan () is a county-level city located in Quzhou prefecture-level city, in the southwest of Zhejiang Province, China, bordering Jiangxi province to the west. Located about 250 kilometers southwest of Hangzhou, the provincial capital, it is .... The outcrop belongs to the Huayansi Formation(华严寺组). References Cambrian geochronology Geological ages {{Geology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jiangshanian
The Jiangshanian is the middle stage of the Furongian series. It follows the Paibian Stage and is succeeded by the still unnamed Stage 10 of the Cambrian. The base is defined as the first appearance of the trilobite ''Agnostotes orientalis'' which is estimated to be million years ago. The Jiangshanian lasted until approximately million years ago. The Cambrian stage was named after Jiangshan, a city in China's Zhejiang province. The GSSP of the Jiangshanian is the "Duibian B Section" (), west of the village of Duibian(碓边), and 10 km north of Jiangshan Jiangshan () is a county-level city located in Quzhou prefecture-level city, in the southwest of Zhejiang Province, China, bordering Jiangxi province to the west. Located about 250 kilometers southwest of Hangzhou, the provincial capital, it is .... The outcrop belongs to the Huayansi Formation(华严寺组). References Cambrian geochronology Geological ages {{Geology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Furongian
The Furongian is the fourth and final epoch and series of the Cambrian. 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 10th stage of the Cambrian. 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' in Mandarin and refers to Hunan which is known as the "lotus state". Definition The lower boundary is defined in the same way as the GSSP of the Paibian Stage. Both begin with the first appearance of the trilobite ''Glyptagnostus reticulatus'' around million years ago. The upper boundary is the lower boundary and GSSP of the Tremadocian Stage which is the first appearance of the conodont ''Iapetognathus f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agnostotes Orientalis
''Agnostotes orientalis'' is a species of agnostid trilobite belonging to the genus '' Agnostotes''. It existed during the Jiangshanian Age ( million years ago) of the Cambrian. It is an important index fossil in biostratigraphy. Description ''Agnostotes orientalis'', like all members of the suborder Agnostina, possesses two thoracic segments, has a cephalon and pygidium that are more or less the same size and shape ( isopygous), and is completely blind. The axial lobe of the cephalon is narrow. At the front of the glabella is a notch (frontal sulcus), a characteristic unique to the species, making it easy to distinguish from other members of the genus. The posterior end of the axial lobe of the pygidium also widens significantly, another distinct characteristic of the species. Along the margins of the pygidium are a pair of very small backward-pointing spines. Both the pygidium and the cephalon are ornamented with small pits (scrobicules) and wrinkles, extending mostly inwards ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paibian
The Paibian is the lowest stage of Furongian series of the Cambrian. It follows the Guzhangian ( 3rd series of the Cambrian) and is succeeded by the Jiangshanian Stage. The base is defined as the first appearance of the trilobite ''Glyptagnostus reticulatus'' around million years ago. The top, or the base of the Jiangshanian is defined as the first appearance of the trilobite ''Agnostotes orientalis'' around million years ago. The name is derived from Paibi, a village in Hunan, China. The GSSP is defined in the "Paibi section" (Wuling Mountains, Huayuan County), an outcrop of the Huaqiao Formation(花桥组). The base is the first occurrence of ''Glyptagnostus reticulatus'' which is 396 m above the base of the Huaqiao Formation Huaqiao may refer to: *Overseas Chinese (华侨), or Huaqiao in pinyin *Huaqiao University (华侨大学), in Quanzhou, Fujian *Huaqiao railway station (花桥站), station of the Shanghai-Nanjing Intercity High-Speed Railway in Shanghai *Huaqiao s ... at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jiangshan
Jiangshan () is a county-level city located in Quzhou prefecture-level city, in the southwest of Zhejiang Province, China, bordering Jiangxi province to the west. Located about 250 kilometers southwest of Hangzhou, the provincial capital, it is the only county-level city in Quzhou. In 1999, Jiangshan's population stood at 563,196. The city is named aptly: Jiang means river and Shan means mountain; a river runs through the city and scenic Mt. Jianglang sits on its border. ''USA Today'' described Jiangshan as a "fairly prosperous city in one of China's most developed provinces".''Global TEFL'' network The program sends native English-speakers to their network schools to teach English for periods of 2–4 weeks. Aside from these teachers, Jiangshan sees few Westerners because of its relative geographical obscurity. Jiangshan High School is also in Jiangshan. Transportation The area is served by Jiangshan railway station Jiangshan railway station is a railway station in Jiangs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian Stage 10
Stage 10 of the Cambrian is the still unnamed third and final stage of the Furongian series. It follows the Jiangshanian and precedes the Ordovician Tremadocian Stage. The proposed lower boundary is the first appearance of the trilobite '' Lotagnostus americanus'' around million years ago, but other fossils are also being discussed ( see below). The upper boundary is defined as the appearance of the conodont ''Iapetognathus fluctivagus'' which marks the beginning of the Tremadocian and is radiometrically dated as million years ago. Naming The 10th stage of the Cambrian has not been formally named by the ICS yet, although a number of local names exist. Several authors favor the name "Lawsonian" after Lawson Cove, in the Wah Wah Mountains of Utah. The lower part of the North American Skullrockian Stage corresponds roughly to the Cambrian Stage 10. Stratotype The ICS is still discussing which geological section and biostratigraphic marker will be used to define the base of ... [...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] |
Trilobite
Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period () and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last extant trilobites finally disappeared in the mass extinction at the end of the Permian about 252 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described. By the time trilobites first appeared in the fossil record, they were already highly diversified and geographically dispersed. Because trilobites had wide diversity and an easily fossilized exoskeleton, they left an extensive fossil record. The stu ... [...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] |
International Commission On Stratigraphy
The International Commission on Stratigraphy (ICS), sometimes referred to unofficially as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigraphy, stratigraphical, geology, geological, and chronology, geochronological matters on a global scale. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First Appearance Datum
First appearance datum (FAD) is a term used by geologists and paleontologists to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest fossil discovered, to date, of a particular species. A related term is last appearance datum (LAD), the last appearance of a species in the geologic record. FADs are frequently used to designate segments in the geologic time scale. A given FAD can be used to define a Global Boundary Stratotype Section and Point (GSSP). For example, the beginning of the Tremadocian Stage of the Ordovician Period is marked by the first appearance of the conodont ''Iapetognathus fluctivagus'' in the geologic record. This occurs in bed 23 of the rock formation known as the Green Point section, located in western Newfoundland, as well as in geologically correlated strata in many parts of the world. However, diachronous FADs can be problematic for correlating chronostratigraphic units, particularly o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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