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The Silurian (/ s ɪ ˈ lj ʊər i. ən, s aɪ-/ sih-LURE-ee-ən, sy-) [8] [9] [10] is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.1 million years ago , to the beginning of the Devonian Period, 419.62 Mya. [11] The Silurian is the third and shortest period of the Paleozoic Era, and the ...
In the geological timescale, the Llandovery Epoch (from 443.8 ± 1.5 million years ago to 433.4 ± 0.8 million years ago) occurred at the beginning of the Silurian Period. . The Llandoverian Epoch follows the massive Ordovician-Silurian extinction events, which led to a large decrease in biodiversity and an opening up of ecosyste
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 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.
c. 486.85 ± 1.5 Ma – Beginning of the Ordovician and the end of the Cambrian Period. c. 485 Ma – First jawless fish – radiation of Thelodont fish into the Silurian; c. 460 Ma – First crinoids evolve. c. 450 Ma – Late Ordovician microfossils of scales indicate the earliest evidence for the existence of jawed fish or Gnathostomata.
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.
During the Late Silurian and Devonian, land plants, assisted by fungi, [45] [46] underwent a hugely significant phase of evolution known as the Silurian-Devonian Terrestrial Revolution. [47] [48] Their maximum height went from 30 cm at the start of the Devonian, to 30 m archaeopterids, [49] at the end of the period.
In the geologic timescale, the Rhuddanian is the first age of the Silurian Period and of the Llandovery Epoch. The Silurian is in the Paleozoic Era of the Phanerozoic Eon. [9] The Rhuddanian Age began 443.8 ± 1.5 Ma and ended 440.8 ± 1.2 Ma (million years ago). It succeeds the Hirnantian Age (the last age of the Ordovician Period) and ...