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Saturday, July 4, 2009 |
Saturday, July 4, 2009 |
Photo: Once Lush Sahara Dried Up Over Millennia, Study SaysA new analysis of the lake's bottom deposits suggests that the Sahara turned from green savanna to arid desert more slowly than previously thought. Photograph courtesy S. Kröpelin/University of Cologne
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ADVERTISEMENTNATIONAL GEOGRAPHIC'S PHOTO OF THE DAY |
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