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The cause for the end of the Late Ordovician Glaciation is a matter of intense research, but evidence shows that the deglaciation in the terminal Hirnantian may have occurred abruptly, as Silurian strata marks a significant change from the glacial deposits left during the Late Ordovician. [66]
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]
Download as PDF; Printable version; In other projects Wikidata item; ... Pages in category "Ordovician plants" The following 6 pages are in this category, out of 6 ...
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 ...
Fossils of this plant have been recorded in Australia, [39] [40] Canada, [41] and China. [42] Eohostimella heathana is an early, probably terrestrial, "plant" known from compression fossils [43] of Early Silurian (Llandovery) age. [44] The chemistry of its fossils is similar to that of fossilised vascular plants, rather than algae. [43]
First, the cooling global climate was probably especially detrimental because the biota were adapted to an intense greenhouse, especially because most shallow sea habitats in the Ordovician were located in the tropics. [62] The southward shift of the polar front severely contracted the available latitudinal range of warm-adapted organisms. [63]
Download as PDF; Printable version; In other projects ... First land plant spores [1] ... Ordovician meteor event [2] [3] Subdivision of the Ordovician according to ...
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 ...