Radar images taken from the space shuttle confirm that a lake broader than Lake Erie once sprawled a few hundred kilometers west of the Nile, researchers report in the December issue of Geology.
Since the lake first appeared around 250,000 years ago, it would have ballooned and shrunk until finally petering out around 80,000 years ago.
Knowing where and when such oases existed could help archaeologists understand the environment Homo sapiens traveled while migrating out of Africa for the first time, says team leader Ted Maxwell, a geologist at the Smithsonian National Air and Space Museum in Washington, D.C. Modern humans arose in Africa about 200,000 years ago.
Other studies have found evidence of mega-lakes in Chad, Libya and Sudan at various points over the past 250,000 years. The new study targeted Egypt, some 400 kilometers west of the Nile, where in the 1980s researchers reporting finding fish fossils in the desert.
More informations: Wired