Prehistoric rocks offer clues about climate change

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Wan Yang (left) with  Xiaorong Luo of the Institute of Geology and Geophysics, Chinese Academy of Sciences, at a site where they study sedimentary rocks in the Tarim Basin. Photo submitted

For most of the past decade, Wan Yang has spent his summers camping and hiking in the Bogda Mountains in northwest China, collecting rock samples that predate dinosaurs by millions of years. His goal? To better understand the Earth’s climate history and gain clues about future climate change.

Wan Yang examines rock samples that predate dinosaurs by millions of years in an effort to better understand the history of the Earth’s climate. Photos by B.A. Rupert

“The formation of rocks has everything to do with climate,” says Yang, associate professor of geological sciences and engineering. “Different climate settings have different sediments, soil types and vegetation. The beauty of the geological record is that we can see changes in the past, which gives us some guide to predict future changes.”

Yang spends his summers working in the high desert of northwest China because it’s one of the few places to have a land record from Pangea, the supercontinent that existed between 200 million and 350 million years ago. Land records are hard to preserve because they are exposed to the elements, Yang says, so most research has typically been done using marine records instead. The seawater offers better protection of the rocks below, as Missouri S&T students saw first-hand in June during a field course led by Yang and two other professors from Trinity and Guizhou universities in southern China.

“Most people don’t realize that 250 million years ago the greatest, most severe mass extinction in the Earth’s history occurred,” Yang says.

Yang returned to Rolla in early August with more than 300 pounds of volcanic ash (known as tuff). Zircon, a special mineral in the ash, can be used to accurately date the rocks and will help to more precisely determine the pace of the terrestrial mass extinction and climatic change, he says.

“There are so many things we would like to know,” he says.

By Mindy Limback

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This story was originally published in Missouri S&T Magazine.

Read additional stories from the Fall/Winter 2012 issue.

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