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Ludfordian
In the geologic timescale, the Ludfordian is the upper of two chronostratigraphic stages within the Ludlow Series. Its age is the late Silurian Period, and within both the Palaeozoic Era and Phanerozoic Eon. The rocks assigned to the Ludfordian date to between 425.6 ± 0.9 Ma and 423.0 ± 2.3 Ma (million years ago). The Ludfordian Stage succeeds the Gorstian Stage and precedes the Pridoli Epoch. It is named for the village of Ludford in Shropshire, England. The GSSP for the Ludfordian is represented as a thin shale seam, coincident with the base of the Leintwardine Formation, overlying the Bringewood Formation in England. Paleoclimate The Lau event is a rapid pulse of cooling during the Ludfordian, about ; it is identified by a pulse of extinctions and oceanic changes. It is one of the series of fast sea-level and excursions in oxygen isotope ratios that signal fast switches between warm and cold climate states, characteristic of the Silurian climatic instability. The Lau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ludfordian
In the geologic timescale, the Ludfordian is the upper of two chronostratigraphic stages within the Ludlow Series. Its age is the late Silurian Period, and within both the Palaeozoic Era and Phanerozoic Eon. The rocks assigned to the Ludfordian date to between 425.6 ± 0.9 Ma and 423.0 ± 2.3 Ma (million years ago). The Ludfordian Stage succeeds the Gorstian Stage and precedes the Pridoli Epoch. It is named for the village of Ludford in Shropshire, England. The GSSP for the Ludfordian is represented as a thin shale seam, coincident with the base of the Leintwardine Formation, overlying the Bringewood Formation in England. Paleoclimate The Lau event is a rapid pulse of cooling during the Ludfordian, about ; it is identified by a pulse of extinctions and oceanic changes. It is one of the series of fast sea-level and excursions in oxygen isotope ratios that signal fast switches between warm and cold climate states, characteristic of the Silurian climatic instability. The Lau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lau Event
The Lau event was the last of three relatively minor mass extinctions (the Ireviken, Mulde, and Lau events) during the Silurian period. It had a major effect on the conodont fauna, but barely scathed the graptolites, though they suffered an extinction very shortly thereafter termed the Kozlowskii event that some authors have suggested was coeval with the Lau event and only appears asynchronous due to taphonomic reasons. It coincided with a global low point in sea level caused by glacioeustasy and is closely followed by an excursion in geochemical isotopes in the ensuing late Ludfordian faunal stage and a change in depositional regime. Biological impact The Lau event started at the beginning of the late Ludfordian, a subdivision of the Ludlow stage, about . Its strata are best exposed in Gotland, Sweden, taking its name from the parish of Lau. Its base is set at the first extinction datum, in the Eke beds, and despite a scarcity of data, it is apparent that most major groups suf ... [...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 (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 standardized international units of geologic 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 define gl ... [...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 (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 standardized international units of geologic 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 define gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Period
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 (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 standardized international units of geologic 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 define gl ... [...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 (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 standardized international units of geologic 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 define gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ludford, Shropshire
Ludford is a small village and civil parish in south Shropshire, England. The parish is situated adjacent to the market town of Ludlow and was, until 1895, partly in Herefordshire. The village is on the south bank of the River Teme, with Ludlow on the north bank, and is connected to the town by the grade I listed Ludford Bridge. The village is geologically notable with its Ludford Corner. History and geography Etymology The place name means the ford at the loud waters ("lud"); Ludlow's name means the hill ("low") by the loud waters. The loud waters are those of the River Teme, which flow rapidly through the area (now largely tamed by weirs). Domesday Book Ludford, Steventon, and the Sheet are all mentioned in the Domesday Book of 1086 as manors. They existed prior to the town of Ludlow, which grew up during or after the construction of the Norman castle there. Shropshire and Herefordshire Historically the parish was divided between Shropshire and Herefordshire and the vill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ludlow Series
In the geological timescale, the Ludlow Epoch (from 427.4 ± 0.5 million years ago to 423.0 ± 2.3 million years ago) occurred during the Silurian Period, after the end of the Homerian Age. It is named for the town of Ludlow in Shropshire, England. The Ludlow Epoch is subdivided into two stages: Gorstian and Ludfordian. Paleontology Arthropods See also *Ludlow Group The Ludlow Group are geologic formations deposited during the Ludlow epoch of the Silurian period in the British Isles, in areas of England, Ireland, Scotland, and Wales. Formations This group contains the following formations in descending or ... References *03 Geological epochs {{geochronology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gorstian
In the geologic timescale, the Gorstian is an age of the Ludlow Epoch of the Silurian Period of the Paleozoic Era of the Phanerozoic Eon that is comprehended between 427.4 ± 0.5 Ma and 425.6 ± 0.9 Ma (million years ago), approximately. The Gorstian Age succeeds the Homerian Age and precedes the Ludfordian Age. The age is named after Gorsty village southwest of Ludlow Ludlow () is a market town in Shropshire, England. The town is significant in the history of the Welsh Marches and in relation to Wales. It is located south of Shrewsbury and north of Hereford, on the A49 road which bypasses the town. The t .... The base of the age is marked by '' Graptolites tumescens'' and '' Graptolites incipiens''. The type section is located in a quarry in the Elton Formation at Pitch Coppice, Shropshire, United Kingdom. References Ludlow epoch Silurian geochronology {{geochronology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian
The Silurian ( ) is a geologic period and system spanning 24.6 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 shortest period of the Paleozoic Era. 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) became fully terrestrialized. A significant evolutionary milestone during ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ludlow Epoch
In the geological timescale, the Ludlow Epoch (from 427.4 ± 0.5 million years ago to 423.0 ± 2.3 million years ago) occurred during the Silurian Period, after the end of the Homerian Age. It is named for the town of Ludlow in Shropshire, England. The Ludlow Epoch is subdivided into two stages: Gorstian and Ludfordian. Paleontology Arthropods See also *Ludlow Group References Ludlow epoch, Silurian geochronology, *03 Geological epochs Ludlow first appearances, {{geochronology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronostratigraphic
Chronostratigraphy is the branch of stratigraphy that studies the ages of rock strata in relation to time. The ultimate aim of chronostratigraphy is to arrange the sequence of deposition and the time of deposition of all rocks within a geological region, and eventually, the entire geologic record of the Earth. The standard stratigraphic nomenclature is a chronostratigraphic system based on palaeontological intervals of time defined by recognised fossil assemblages (biostratigraphy). The aim of chronostratigraphy is to give a meaningful age date to these fossil assemblage intervals and interfaces. Methodology Chronostratigraphy relies heavily upon isotope geology and geochronology to derive hard dating of known and well defined rock units which contain the specific fossil assemblages defined by the stratigraphic system. In practice, as it is very difficult to isotopically date most fossils and sedimentary rocks directly, inferences must be made in order to arrive at an age dat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
