When the Earth Gets Sick: Most Mass Extinctions Happened Slowly

Pangaea

Earth in the Permian period. Illustration: Kieff (CC)

Via ScienceDaily:

In geology as in cancer research, the silver bullet theory always gets the headlines and nearly always turns out to be wrong. For geologists who study mass extinctions, the silver bullet is a giant asteroid plunging to earth.But an asteroid is the prime suspect only in the most recent of five mass extinctions, said USC earth scientist David Bottjer. The cataclysm 65 million years ago wiped out the dinosaurs.

“The other four have not been resolvable to a rock falling out of the sky,” Bottjer said. For example, Bottjer and many others have published studies suggesting that the end-Permian extinction 250 million years ago happened in essence because “the earth got sick.”

The latest research from Bottjer’s group suggests a similar slow dying during the extinction 200 million years ago at the boundary of the Triassic and Jurassic eras. The latest research from Bottjer’s group suggests a similar slow dying during the extinction 200 million years ago at the boundary of the Triassic and Jurassic eras.

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