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2016-01-11. Growth rings on rocks give up North American climate secrets.

posted Jan 14, 2016, 11:24 PM by Alan Gould   [ updated Jan 26, 2016, 11:51 AM ]
By Sarah Yang, UC Berkeley News. For GSS Climate Change chapter 7. Excerpt: A research team led by UC Berkeley soil scientists obtained data about precipitation and temperature in North America spanning the past 120,000 years, which covers glacial and interglacial periods during the Pleistocene Epoch. They did this at thousand-year resolutions — a blink of an eye in geologic terms — through a microanalysis of the carbonate deposits that formed growth rings around rocks, some measuring just 3 millimeters thick. “The cool thing that this study reveals is that within soil — an unlikely reservoir given how ‘messy’ most people think it is — there is a mineral that accumulates steadily and creates some of the most detailed information to date on the Earth’s past climates,” said senior author Ronald Amundson, a UC Berkeley professor of environmental science, policy and management. The study, published today in the Proceedings of the National Academy of Sciences, shows the rich potential held within soil deposits known as pedothems, which form growth rings on rocks. The samples used in the study came from Wyoming’s Wind River Basin.... http://news.berkeley.edu/2016/01/11/rings-on-rocks-detail-north-american-paleoclimate/