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Sandbian
The Sandbian is the first stage of the Upper Ordovician. It follows the Darriwilian and is succeeded by the Katian. Its lower boundary is defined as the first appearance datum of the graptolite species '' Nemagraptus gracilis'' around million years ago. The Sandbian lasted for about 5.4 million years until the beginning of the Katian around million years ago. Naming The name Sandbian is derived from the village Södra Sandby (Lund Municipality, Skåne County, Sweden). The name was proposed in 2006. GSSP The GSSP of the Sandbian is the Fågelsång section () at Sularp Brook, east of Lund (Skåne, Sweden). It is an outcrop of shale and mudstone. The lower boundary of the Sandbian is defined as the first appearance datum of graptolite 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Ordovician
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cambrian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Ordovician
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cambrian Per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darriwilian
The Darriwilian is the upper stage of the Middle Ordovician. It is preceded by the Dapingian and succeeded by the Upper Ordovician Sandbian Stage. The lower boundary of the Darriwilian is defined as the first appearance of the graptolite species ''Undulograptus austrodentatus'' around million years ago. It lasted for about 8.9 million years until the beginning of the Sandbian around million years ago. This stage of the Ordovician was marked by the beginning of the Andean-Saharan glaciation. Naming The name Darriwilian is derived from Darriwil, a parish in County of Grant, Victoria (Australia). The name was proposed in 1899 by Thomas Sergeant Hall. GSSP The GSSP of the Darriwilian is the Huangnitang Section () near the village Huangnitang, 3.5 km southwest of Changshan County Town (Zhejiang, China). It is an outcrop of the Ningkuo Formation, consisting of mainly black shale. The lower boundary of the Darriwilian is defined as the first appearance datum of the grapto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sularp Brook
Sularp Brook (), Lund Municipality, Skåne, Sweden, is the location of the Global Boundary Stratotype Section and Point (GSSP) which marks the boundary between the Middle and Late epochs of the Ordovician period on the geologic time scale. The first appearance of the graptolite ''Nemagraptus gracilis'' defines the boundary. The rock section consists primarily of dark-gray shale and mudstone, except for a phosphorite Phosphorite, phosphate rock or rock phosphate is a non-detrital sedimentary rock that contains high amounts of phosphate minerals. The phosphate content of phosphorite (or grade of phosphate rock) varies greatly, from 4% to 20% phosphorus pentoxi ... marker bed 1.4 m above the GSSP, and was probably deposited at a water depth exceeding 100 m. Drill cores have revealed almost identical stratigraphy across an area several km wide. Due to heating, possibly from an intrusive dike, the stratotype is unfit for dating by magnetic analysis, but this lack is compensated by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Södra Sandby
Södra Sandby () is the second largest locality in Lund Municipality, Skåne County, Sweden with 6,136 inhabitants in 2010. It is situated about 10 kilometers east of Lund and 30 kilometers northeast of Malmö. The Sandbian Age of the Ordovician Period of geological time is named for Södra Sandby where the Lindegård Formation crops out.Södra Sandby at Fossilworks
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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] |
Katian
The Katian is the second stage of the Upper Ordovician. It is preceded by the Sandbian and succeeded by the Hirnantian Stage. The Katian began million years ago and lasted for about 7.8 million years until the beginning of the Hirnantian million years ago. During the Katian the climate cooled which started the Late Ordovician glaciation. Naming The name Katian is derived from Katy Lake (Atoka County, Oklahoma, United States). GSSP The GSSP of the Katian Stage is the Black Knob Ridge Section in southeastern Oklahoma (United States). It is an outcrop of the Womble Shale and the Bigfork Chert, the latter containing the lower boundary of the Katian. The lower boundary is defined as the first appearance datum of the graptolite 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 L ... ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oklahoma
Oklahoma (; Choctaw language, Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a U.S. state, state in the South Central United States, South Central region of the United States, bordered by Texas on the south and west, Kansas on the north, Missouri on the northeast, Arkansas on the east, New Mexico on the west, and Colorado on the northwest. Partially in the western extreme of the Upland South, it is the List of U.S. states and territories by area, 20th-most extensive and the List of U.S. states and territories by population, 28th-most populous of the 50 United States. Its residents are known as Oklahomans and its capital and largest city is Oklahoma City. The state's name is derived from the Choctaw language, Choctaw words , 'people' and , which translates as 'red'. Oklahoma is also known informally by its List of U.S. state and territory nicknames, nickname, "Sooners, The Sooner State", in reference to the settlers who staked their claims on land before the official op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five major unincorporated territories, nine United States Minor Outlying Islands, Minor Outlying Islands, and 326 Indian reservations. The United States is also in Compact of Free Association, free association with three Oceania, Pacific Island Sovereign state, sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Palau, Republic of Palau. It is the world's List of countries and dependencies by area, third-largest country by both land and total area. It shares land borders Canada–United States border, with Canada to its north and Mexico–United States border, with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the List of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sweden
Sweden, ; fi, Ruotsi; fit, Ruotti; se, Ruoŧŧa; smj, Svierik; sje, Sverji; sju, Sverje; sma, Sveerje or ; yi, שוועדן, Shvedn; rmu, Svedikko; rmf, Sveittiko. formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic country and the List of European countries by area, fifth-largest country in Europe. The Capital city, capital and largest city is Stockholm. Sweden has a population of 10.5 million, and a low population density of ; around 87% of Swedes reside in urban areas in the central and southern half of the country. Sweden’s urban areas together cover 1.5% of its land area. Because the country is so long, ranging from 55th parallel north, 55°N to 69th parallel north, 69°N, the climate of Sweden is diverse. Sweden has been inhabited since Prehistoric Sweden, prehistoric times, . T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
