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The Ordovician–Silurian extinction events may have been caused by an ice age that occurred at the end of the Ordovician Period, due to the expansion of the first terrestrial plants, [54] as the end of the Late Ordovician was one of the coldest times in the last 600 million years of Earth's history.
South of the Brigantes, the geographer Ptolemy reported three tribes whose territories stretched from the Irish Sea to the North Sea. The Ordovices occupied the westward lands and had two noteworthy cities, Branogenium which was located 195 Roman miles from London, most likely at Leintwardine, and Mediolanum which was located 200 Roman miles from London.
The Late Ordovician mass extinction (LOME), sometimes known as the end-Ordovician mass extinction or the Ordovician-Silurian extinction, is the first of the "big five" major mass extinction events in Earth's history, occurring roughly 445 million years ago (Ma). [1]
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 452.8 million years ago and lasted for about 7.6 million years until the beginning of the Hirnantian 445.2 million years ago. [7] During the Katian the climate cooled which started the Late Ordovician ...
The Ordovician Period was the geologic period and system that the Earth was in when the rings are believed to have formed. The Ordovician spanned from 486.85 million years ago to 443.1 million years ago. During this period, an event known as the Ordovician meteor event occurred, when a high level of L chondrite meteorites hit Earth. The ...
This timeline of Ordovician research is a chronological listing of events in the history of geology and paleontology focused on the study of earth during the span of time lasting from 485.4–443.4 million years ago and the legacies of this period in the rock and fossil records.
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 458.2 million years ago.
The Ordovician Period of the Paleozoic Era, in the Phanerozoic Eon.. This category contains events which happened in the Ordovician, a division of the geologic time scale.See geologic time scale for information about its divisions and how they relate to each other.