Thursday, November 02, 2006
About 350 million years ago, at the boundary of the Devonian and Carboniferous ages, the climate changed. There was no one around to record it, but there are records nonetheless in the rocks deposited by glaciers and in tissues preserved in fossils of ancient life.
"Events at the transition had terrific biological impact, marked by extinctions and the beginnings of new life forms," said Stephen Scheckler (faculty info) of Blacksburg, professor of biological sciences and geosciences at Virginia Tech. He reported on evidence of climate change that he found in the fossils of the ancestors of modern trees at the at the Geological Society of America's national meeting in Philadelphia October 22-25, 2006.
"This glaciation was not widely understood until recently," Scheckler said. "It was a worldwide event. The Europeans recognize the extinctions as the Hangenburg event, documented in a black shale deposit that contains a series of fauna changes. But the eastern United States was at a tropical latitude at that time, so the flora and fauna show less impact - but it is there. It is believed to be a time of coldness, because there was less diversity, but it is a subtle signal."
Continued at "Ancestor of Modern Trees Preserves Record of Ancient Climate Change"
Stephen Scheckler's presentation was titled "Woody plant growth as a proxy for climate change at the Devonian-Carboniferous boundary," (Abstract).
Also see "Learning about life from the top of the world" from Virginia Tech Magazine.
And 'Unstoppable Global Warming: Every 1500 Years' - Hardcover (UK | US) | Paperback (UK | US) - see "'Unstoppable Global Warming: Every 1500 Years' (Book + Audio Interview)"
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