[font face=Times, Serif][font size=5]Global Extinction: Gradual Doom Is Just As Bad As Abrupt[/font]
[font size=4]Around 250 million years ago, most life on Earth was wiped out in an extinction known as the Great Dying. A team led by University of Cincinnati geologist Thomas J. Algeo finds that the end came slowly from thousands of centuries of volcanic activity.[/font]
Date: 2/3/2012 12:00:00 AM
By: Greg Hand
Phone: (513) 556-1822
Photos By: Ashley Kempher
[font size=3]A painstakingly detailed investigation shows that mass extinctions need not be sudden events. The deadliest mass extinction of all took a long time to kill 90 percent of Earths marine life, and it killed in stages, according to a newly published report.
Thomas J. Algeo, professor of geology at the University of Cincinnati, worked with 13 co-authors to produce a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic. Their analysis, published Feb. 3 in the
Geological Society of America Bulletin, provides strong evidence that Earths biggest mass extinction phased in over hundreds of thousands of years.
About 252 million years ago, at the end of the Permian period, Earth almost became a lifeless planet. Around 90 percent of all living species disappeared then, in what scientists have called The Great Dying. Algeo and colleagues have spent much of the past decade investigating the chemical evidence buried in rocks formed during this major extinction.
The world revealed by their research is horrific and alien: a devastated landscape, barren of vegetation and scarred by erosion from showers of acid rain, huge dead zones in the oceans, and runaway greenhouse warming leading to sizzling temperatures.
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