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Westphalian (stage)
The Westphalian is a regional stage or age in the regional stratigraphy of northwest Europe, with an age between roughly 315 and 307 Ma (million years ago). It is a subdivision of the Carboniferous System or Period and the regional Silesian Series. The Westphalian is named for the region of Westphalia ( German: ''Westfalen'') in western Germany where strata of this age occur. The Coal Measures of England and Wales are also largely of Westphalian age, though they also extend into the succeeding Stephanian. The Westphalian is preceded by the Namurian Stage/Age (which corresponds to the Millstone Grit Series of Great Britain) and succeeded by the Stephanian Stage/Age (which corresponds to the uppermost part of the Coal Measures of Great Britain). In the official geologic time scale of the International Commission on Stratigraphy (ICS), the Westphalian is placed within the Pennsylvanian Subsystem/Subperiod (323-299 Ma) of the Carboniferous System/Period. As a regionally defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stage (stratigraphy)
In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries. Rock series are divided into stages, just as geological epochs are divided into ages. Stages are divided into smaller stratigraphic units called chronozones or substages, and added together into superstages. The term faunal stage is sometimes used, referring to the fact that the same fauna (animals) are found throughout the layer (by definition). Definition Stages are primarily defined by a consistent set of fossils ( biostratigraphy) or a consistent magnetic polarity (see paleomagnetism) in the rock. Usually one or more index fossils that are common, found worldwide, easily recognized, and limited to a single, or at most a few, stages are used to define the stage's bottom. Thus, f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Millstone Grit
Millstone Grit is any of a number of coarse-grained sandstones of Carboniferous age which occur in the British Isles. The name derives from its use in earlier times as a source of millstones for use principally in watermills. Geologists refer to the whole suite of rocks that encompass the individual limestone beds and the intervening mudstones as the Millstone Grit Group. The term Millstone Grit Series was formerly used to refer to the rocks now included within the Millstone Grit Group together with the underlying Edale Shale Group. The term gritstone describes any sandstone composed of coarse angular grains, and specifically refers to such sandstones within the Pennines and neighbouring areas of Northern England. Geographical occurrence Rocks assigned to the Millstone Grit Group occur over a wide area of Northern England, where they are a hugely important landscape-forming element of the rock succession. They also occur in parts of northeast Wales and northwest Ireland. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Maritimes
The Maritimes, also called the Maritime provinces, is a region of Eastern Canada consisting of three provinces: New Brunswick, Nova Scotia, and Prince Edward Island. The Maritimes had a population of 1,899,324 in 2021, which makes up 5.1% of Canada's population. Together with Canada's easternmost province, Newfoundland and Labrador, the Maritime provinces make up the region of Atlantic Canada. Located along the Atlantic coast, various aquatic sub-basins are located in the Maritimes, such as the Gulf of Maine and Gulf of St. Lawrence. The region is located northeast of New England in the United States, south and southeast of Quebec's Gaspé Peninsula, and southwest of the island of Newfoundland. The notion of a Maritime Union has been proposed at various times in Canada's history; the first discussions in 1864 at the Charlottetown Conference contributed to Canadian Confederation. This movement formed the larger Dominion of Canada. The Mi'kmaq, Maliseet and Passamaquodd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turkey
Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armenia, Azerbaijan, and Iran to the east; Iraq, Syria, and the Mediterranean Sea to the south; and the Aegean Sea, Greece, and Bulgaria to the west. Turkey is home to over 85 million people; most are ethnic Turkish people, Turks, while ethnic Kurds in Turkey, Kurds are the Minorities in Turkey, largest ethnic minority. Officially Secularism in Turkey, a secular state, Turkey has Islam in Turkey, a Muslim-majority population. Ankara is Turkey's capital and second-largest city. Istanbul is its largest city and economic center. Other major cities include İzmir, Bursa, and Antalya. First inhabited by modern humans during the Late Paleolithic, present-day Turkey was home to List of ancient peoples of Anatolia, various ancient peoples. The Hattians ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assemblage Zone
In biostratigraphy, biostratigraphic units or biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa, as opposed to a lithostratigraphic unit which is defined by the lithological properties of the surrounding rock. A biostratigraphic unit is defined by the zone fossils it contains. These may be a single taxon or combinations of taxa if the taxa are relatively abundant, or variations in features related to the distribution of fossils. The same strata may be zoned differently depending on the diagnostic criteria or fossil group chosen, so there may be several, sometimes overlapping, biostratigraphic units in the same interval. Like lithostratigraphic units, biozones must have a type section designated as a stratotype. These stratotypes are named according to the typical taxon (or taxa) that are found in that particular biozone. The boundary of two distinct biostratigraphic units is called a ''biohorizon''. Biozones can be furt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonoidea
Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family Nautilidae). The earliest ammonoids appeared during the Emsian stage of the Early Devonian (410.62 million years ago), with the last species vanishing during or soon after the Cretaceous–Paleogene extinction event (66 million years ago). They are often called ammonites, which is most frequently used for members of the order Ammonitida, the only remaining group of ammonoids from the Jurassic up until their extinction. Ammonoids exhibited considerable diversity over their evolutionary history, with over 10,000 species having been described. Ammonoids are excellent index fossils, and they have been frequently used to link rock layers in which a particular species or genus is found to specific Geologic time scale, geologic time periods. Their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miospore
Cryptospores are microscopic fossilized spores produced by embryophytes (land plants). They first appear in the fossil record during the middle of the Ordovician period, as the oldest fossil evidence for the colonization of land by plants. A similar (though broader) category is miospores, a term generally used for spores smaller than 200 μm. Both cryptospores and miospores are types of palynomorphs. Cryptospores, which occur as permanent tetrads, dyads, or hilate monads, sometimes with additional wall envelopes, dominated fossil assemblages for approximately 60 million years, first appearing around 470 million years ago during the Ordovician Period. They underwent rapid diversification during what Jane Gray (1993) called the Eoembryophytic epoch, but experienced an abrupt decline in diversity and abundance around 410 Ma during the latest Lochkovian (Early Devonian), with only a few forms persisting into the Emsian period. In contrast, trilete monads began diversifying around 430 Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrofossil
Macrofossils, also known as megafossils, are the preserved remnants of organic beings and their activities that are large enough to be visible without a microscope. The term ''macrofossil'' stands in opposition to the term microfossil. Microfossils, by contrast, require substantial magnification for evaluation by fossil-hunters or professional paleontologists. As a result, most fossils observed in the field and most specimens are macrofossils. Macrofossils come in many varieties and form in various ways depending on their environment and what is being fossilized including plant, fungi and animal remnants. Historical background Etymology The origins of the term macrofossil dates back to 1937 and was first used by G. D. Hanna, a US paleontologist and malacologist. Scientific thought Macrofossils have been subject to analysis since ancient times. Several Greek philosophers used fossilized shellfish to theorize the land was once covered by oceans. Macrofossils of body parts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Index Fossils
Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them.Hine, Robert. "Biostratigraphy." ''Oxford Reference: Dictionary of Biology'', 8th ed., Oxford University Press, 2019. The primary objective of biostratigraphy is ''correlation'', demonstrating that a particular horizon in one geological section represents the same period of time as another horizon at a different section. Fossils within these strata are useful because sediments of the same age can look completely different, due to local variations in the sedimentary environment. For example, one section might have been made up of clays and marls, while another has more chalky limestones. However, if the fossil species recorded are similar, the two sediments are likely to have been laid down around the same time. Ideally these fossils are used to help identify biozones, as they make up the basic biostratigraphy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kasimovian
The Kasimovian is a geochronologic age or chronostratigraphic stage in the ICS geologic timescale. It is the third stage in the Pennsylvanian (late Carboniferous), lasting from to Ma.; 2004: ''A Geologic Time Scale 2004'', Cambridge University Press. The Kasimovian Stage follows the Moscovian and is followed by the Gzhelian. The Kasimovian saw an extinction event which occurred around 305 mya, referred to as the Carboniferous Rainforest Collapse. It roughly corresponds to the Missourian in North American geochronology and the Stephanian in western European geochronology. Name and definition The Kasimovian is named after the Russian city of Kasimov. The stage was split from the Moscovian in 1926 by Boris Dan'shin (1891-1941), who gave it the name ''Teguliferina horizon''. The name was posthumously changed to ''Kasimov horizon'' by Dan'shin in 1947. The name Kasimovian was introduced by Georgy Teodorovich in 1949. The base of the Kasimovian Stage is at the base of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moscovian (Carboniferous)
The Moscovian is in the International Commission on Stratigraphy, ICS geologic timescale a stage (stratigraphy), stage or age (geology), age in the Pennsylvanian (geology), Pennsylvanian, the youngest system (stratigraphy), subsystem of the Carboniferous. The Moscovian age lasted from to Megaannum, Ma, is preceded by the Bashkirian and is followed by the Kasimovian. The Moscovian overlaps with the European regional Westphalian (stage), Westphalian stage and the North American Atokan and Desmoinesian stages. Name and definition The Moscovian Stage was introduced by Sergei Nikitin (geologist), Sergei Nikitin (1850 - 1909) in 1890, using brachiopods in the Moscow Basin of European Russia. Nikitin named the stage after Moscow, then a major city and now the capital of Russia. The base of the Moscovian is close to the first appearances of the conodonts ''Declinognathodus donetzianus'' and ''Idiognathoides postsulcatus'' or otherwise the fusulinid ''Aljutovella aljutovica''. Because t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bashkirian
The Bashkirian is in the International Commission on Stratigraphy geologic timescale the lowest stage (stratigraphy), stage or oldest age (geology), age of the Pennsylvanian (geology), Pennsylvanian. The Bashkirian age lasted from to Mega annum, Ma, is preceded by the Serpukhovian and is followed by the Moscovian (Carboniferous), Moscovian. The Bashkirian overlaps with the upper part of the Namurian and lower part of the Westphalian (stage), Westphalian stages from regional European stratigraphy. It also overlaps with the North American Morrowan and Atokan stages and the Chinese Luosuan and lower Huashibanian stages. Name and definition The Bashkirian was named after Bashkiria, the then Russian name of the republic of Bashkortostan in the southern Ural Mountains of Russia, home of the Bashkir people. The stage was introduced by Russian stratigrapher Sofia Viktorovna Semikhartova, Sofia Semikhatova in 1934. The base of the Bashkirian is at the first appearance of conodont spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
