Cambrian–Ordovician extinction events

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The Cambrian–Ordovician extinction event occurred approximately 488 million years ago. It was the first major extinction event in the Phanerozoic eon and it eliminated many brachiopods and conodonts, and severely reduced the number of trilobite species. The Cambrian–Ordovician event ended the Cambrian period, and led into the Ordovician period in the Paleozoic era. The subsequent Ordovician–Silurian extinction events rendered 49% of genera of fauna on Earth extinct.

[edit] Theories of Cambrian-Ordovician extinction event

• Glaciation
• Depletion of oxygen in marine waters

[edit] See also

• Geological timescale
• Cambrian Furongian epoch
• Ordovician Lower/Early epoch

[edit] Further reading

• Gradstein, Felix, James Ogg, and Alan Smith, eds., 2004. A Geologic Time Scale 2004 (Cambridge University Press).
• Hallam, A. and Paul B. Wignall, 1997. Mass extinctions and their aftermath (Oxford University Press).
• Webby, Barry D. and Mary L. Droser, eds., 2004. The Great Ordovician Biodiversification Event (Columbia University Press).

[edit] External links

• Early Ordovician Climate