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In fact, the Hirnantian (also known as the End Ordovician and the Ordovician-Silurian) mass extinction event represents the second largest such event in geologic history. Approximately 85% of marine (sea-dwelling) species died. Only the End-Permian mass extinction was larger. Unlike many smaller extinction events, however, the long-term ...
The Late Ordovician Glaciation coincided with the second largest of the five major extinction events, known as the Late Ordovician mass extinction. This period is the only known glaciation to occur alongside of a mass extinction event. The extinction event consisted of two discrete pulses.
Carbon dioxide levels were very high at the Ordovician period's beginning. [44] By the late Early Ordovician, the Earth cooled, [45] giving way to a more temperate climate in the Middle Ordovician, [46] with the Earth likely entering the Early Palaeozoic Ice Age during the Sandbian, [47] [48] and possibly as early as the Darriwilian [49] or ...
A "greenhouse Earth" is a period during which no continental glaciers exist anywhere on the planet. [6] Additionally, the levels of carbon dioxide and other greenhouse gases (such as water vapor and methane) are high, and sea surface temperatures (SSTs) range from 28 °C (82.4 °F) in the tropics to 0 °C (32 °F) in the polar regions. [7]
Pages in category "Ordovician plants" The following 6 pages are in this category, out of 6 total. This list may not reflect recent changes. C. Casterlorum; Chaetocladus;
Although there was a longer cooling trend in Middle and Lower Ordovician, the most severe and abrupt period of glaciation occurred in the Hirnantian stage, which was bracketed by both pulses of the extinction. [48] The rapid continental glaciation was centered on Gondwana, which was located at the South Pole in the Late Ordovician.
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 Floian is the second stage of the Ordovician Period. It succeeds the Tremadocian with which it forms the Lower Ordovician series. It precedes the Dapingian Stage of the Middle Ordovician. The Floian extended from 477.1 to 471.3 million years ago. [7]