Monday, January 24, 2011

Canadians probe what wiped out most life on Earth | Canada | News | Toronto Sun

CALGARY – Calgary researchers say they've found evidence to support the idea that toxic volcanic ash helped cause the world's largest extinction.

About 250 million years ago, 95% of life in the sea and 70% of life on land was wiped out during the Permian extinction.

"In terms of its relevance, we're looking at the biggest extinction in Earth's history. It wiped the world clean," said Stephen Grasby, a research scientist at Natural Resources Canada (NRC) and adjunct professor in the University of Calgary's geoscience department.

Unlike the annihilation of the dinosaurs -- which happened 65 million years ago and is widely believed to have been caused, at least in part, by the impact of a meteorite -- the catalyst of the Permian extinction has never been clear.

Researchers have, in the past, suggested massive volcanic eruptions could have generated enough greenhouse gases to instigate unstoppable global warming.

Now Grasby and his colleagues -- Benoit Beauchamp, a professor in the U of C's geoscience department, and Dr. Hamed Sanei, adjunct U of C professor and NRC researcher -- say coal ash layers found in Canada's High Arctic suggests the first direct confirmation ash may have played a role.

"It's that direct proof that there was coal combustion going on at that time," said Grasby.

At the time of the extinction, Earth only had one large land mass called Pangaea.

Canadians probe what wiped out most life on Earth | Canada | News | Toronto Sun

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