Earth Sciences 2240F/G Lecture Notes - Lecture 18: Caloris Planitia, Mare Imbrium, East Antarctic Ice Sheet
20 Apr 2016
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Document Summary
The end of the permian period is pegged at 251. 4 million years ago (a slight error on the geological time scale, which says 251. 0). It is marked all over the world as signifying the most catastrophic mass extinction ever: in the words of an eminent scientist, earth came very close to losing life completely . Up to 96% of all marine species and 70% of all terrestrial species died all in less than 1 million years. Even insects which had pretty much escaped previous extinctions suffered a mass extinction. The exact pattern of the extinctions is disputed, but there appears to be a period of gradual deterioration followed by a catastrophic event. Because organisms all over the world and in all environments suffered the same extinction sequence, the cause or causes were global. However, a wonderful sequence of pristine rocks in southern china and another in eastern greenland have proved very productive and much of the speculation is over.
