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Telychian
In the geologic timescale, the Telychian is the third and final age of the Llandovery Epoch of the Silurian Period of the Paleozoic Era of the Phanerozoic Eon. The Telychian Age was between 438.5 ± 1.2 million years ago (Ma) and 433.4 ± 0.8 Ma. The Telychian Age succeeds the Aeronian Age and precedes the Sheinwoodian Age. The name of the interval is derived from the Pen-lan-Telych Farm near Llandovery, Powys, Wales. It ended with the Ireviken event. Ireviken event The Ireviken event was the first of three relatively minor extinction events (the Ireviken, Mulde, and Lau events) during the Silurian Period. It occurred at the Llandovery/ Wenlock boundary (mid Silurian, ). The event is best recorded at Ireviken, Gotland, where over 50% of trilobite species became extinct; 80% of the global conodont Conodonts, are an extinct group of marine jawless vertebrates belonging to the class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning " cone", and ὀδούς ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian
The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of the Paleozoic Era, and the third of twelve periods of the Phanerozoic Eon. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods ( myriapods, arachnids and hexapods) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Era
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 (a 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 standardised international units of geological 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] |
Pterospathodus
''Pterospathodus'' is an extinct genus of conodont from the Silurian The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of t ... period. Use in stratigraphy The Telychian (Late Llandovery) of Estonia can be defined by five conodont zones (''Pterospathodus eopennatus ssp. n. 1'', ''P. eopennatus ssp. n. 2'', ''P. amorphognathoides angulatus'', ''P. a. lennarti'' and ''P. a. lithuanicus'').An updated Telychian (Late Llandovery, Silurian) conodont zonation based on Baltic faunas. Peep Männik, Lethaia, Volume 40, Issue 1, pages 45–60, March 2007, The Sheinwoodian (Wenlock) is defined between the acritarch biozone 5 and the last appearance of ''Pterospathodus amorphognathoides''. The global boundary stratotype point is in Hughley Brook in Apedale, U.K. References External links ... [...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 (a 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 standardised international units of geological 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 precise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Eon
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 (a 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 standardised international units of geological 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] |
Aeronian
In the geologic timescale, the Aeronian is an geologic age, age of the Llandovery Epoch of the Silurian geologic period, Period of the Paleozoic geologic era, Era of the Phanerozoic geologic eon, Eon that began 440.8 ± 1.2 annum, Ma and ended 438.5 ± 1.1 Ma (million years ago). The Aeronian Age succeeds the Rhuddanian Age and precedes the Telychian Age, all in the same epoch. During the Aeronian the Sedgwickii Event occurred in which graptolite diversity was greatly reduced. This event has been attested in locations such as today's Canada, Libya as well as in La Chilca Formation in Argentina (then part of Gondwana). GSSP The Global Boundary Stratotype Section and Point, GSSP is located in the Trefawr Track section, 500m north of Cwm-coed-Aeron Farm, Wales, United Kingdom, UK. The GSSP lies within the gently-dipping blocky Mudstone, mudstones of the Trefawr Formation, which principally yield abundant and diverse shelly faunas, but also contain enough Graptolithina, graptolites ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sheinwoodian
In the geologic timescale, the Sheinwoodian is the age of the Wenlock Epoch of the Silurian Period of the Paleozoic Era of the Phanerozoic Eon that is comprehended between 433.4 ± 0.8 Ma and 430.5 ± 0.7 Ma (million years ago), approximately. The Sheinwoodian Age succeeds the Telychian Age and precedes the Homerian Age. Definition The Wenlock-Llandovery boundary is defined by the first occurrence of '' Cyrtograptus centrifugus''. The stage is named after Sheinwood village, north of Much Wenlock Much Wenlock is a market town and Civil parishes in England, parish in Shropshire, England; it is situated on the A458 road between Shrewsbury and Bridgnorth. Nearby, to the north-east, is the Ironbridge Gorge and Telford. The civil parish incl .... The Buildwas Formation of Shropshire, United Kingdom contains the type section. References Wenlock epoch Silurian geochronology {{geochronology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Llandovery
Llandovery (; ) is a market town and community (Wales), community in Carmarthenshire, Wales. It lies on the River Tywi and at the junction of the A40 road, A40 and A483 road, A483 roads, about north-east of Carmarthen, north of Swansea and west of Brecon. History Etymology The name of the town derives from ', meaning "church enclosure amid the waters", i.e. between the Tywi and the Afon Brân just upstream of their confluence. A smaller watercourse, the Bawddwr, runs through and under the town. Roman legacy The Roman fort at Llanfair Hill to the north-east of the modern town was known to the Roman Britain, Romans as Alabum. It was built around AD 50–60 as part of a strategy for the conquest of Roman Wales, Wales. A Roman road heads across Mynydd Bach Trecastell to the south-east of Llandovery bound for the fort of Brecon Gaer. Another heads down the Towy valley for Carmarthen, whilst a third makes for the goldmines at Dolaucothi. Norman and medieval castle Attractions in ... [...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] |
Wales
Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic Sea to the south-west. , it had a population of 3.2 million. It has a total area of and over of Coastline of Wales, coastline. It is largely mountainous with its higher peaks in the north and central areas, including Snowdon (), its highest summit. The country lies within the Temperate climate, north temperate zone and has a changeable, Oceanic climate, maritime climate. Its capital and largest city is Cardiff. A distinct Culture of Wales, Welsh culture emerged among the Celtic Britons after the End of Roman rule in Britain, Roman withdrawal from Britain in the 5th century, and Wales was briefly united under Gruffudd ap Llywelyn in 1055. After over 200 years of war, the Conquest of Wales by Edward I, conquest of Wales by King Edward I o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
