Today the remnants of those volcanoes are scattered through India, China and Norway. On their own they were too small to do much harm, but together Isozaki thinks they cooled the climate even further, launching an extinction as bad as the one that would kill the dinosaurs 185 million years later. Then, 10 million years later, the Permian-Triassic extinction struck. "The effects of the superplume were just the first punch of extinction," Isozaki said. "Then came the knockout punch, the Permian-Triassic extinction." Isozaki thinks both "punches" were caused by the same superplume. Ten million years after the smaller volcanoes blew their tops, a much larger volcano, the Siberian Traps, erupted, launching the worst killing in the planet's history. Gregory Retallack of the University of Oregon agrees that the late Permian round of extinction was bad -- as much as 67 percent of species were eradicated. But he doesn't think the two events are related. In the 10 million years after the first punch in the late Permian, he said, life recovered. "The late Permian looks good all over the world," Retallack said. "You've got corals, healthy marine communities, and lots of fossil flora on land." There's no questioning the severity of the Permian-Triassic crisis -- "We almost lost it there," Retallack said -- but whether the two can be traced a single mantle superplume, or they were unrelated, remains a mystery for now. Related Links: |
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