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The Cambrian–Ordovician extinction event, also known as the Cambrian-Ordovician boundary event, [1] was an extinction event that occurred approximately 485 million years ago in the Paleozoic era of the early Phanerozoic eon. [2]
Ordovician: Late Ordovician mass extinction: 445-444 Ma Global cooling and sea level drop, and/or global warming related to volcanism and anoxia [43] Cambrian: Cambrian–Ordovician extinction event: 488 Ma: Kalkarindji Large Igneous Province? [44] Dresbachian extinction event: 502 Ma: End-Botomian extinction event: 517 Ma: Precambrian: End ...
The Cambrian (/ ˈ k æ m b r i. ə n, ˈ k eɪ m-/ KAM-bree-ən, KAYM-) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. [5] The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma.
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 Dresbachian overlies the Middle Cambrian Albertan series, and is the lowest stage of the Upper Cambrian Croixian series, followed by the Franconian stage. The Dresbachian extinction event, about 502 million years ago, was followed by the Cambrian–Ordovician extinction event about 485.4 million years ago.
Since the Cambrian explosion, five further major mass extinctions have significantly exceeded the background extinction rate. The most recent and best-known, the Cretaceous–Paleogene extinction event , which occurred approximately 66 Ma (million years ago), was a large-scale mass extinction of animal and plant species in a geologically short ...
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.
The discovery of Lomankus not only extends the temporal range of the Megacheira into the upper Ordovician, but also adds more evidence to the theory that the Cambrian–Ordovician extinction event was not as severe as once suggested, and the lack of "Cambrian type organisms" in later Paleozoic strata is instead a result of taphonomic bias.