Washington–A dry, sand-covered region of Egypt was home 100,000 years ago to a lake as large as one of the Great Lakes, US researchers say.
Radar images taken from the space shuttle confirm that a lake wider than Lake Erie once existed a few hundred kilometers west of the Nile River, ScienceNews.org reported.
From the time it first appeared about 250,000 years ago, the lake in Egypt's Tushka region would have grown and shrunk periodically until finally drying up about 80,000 years ago, researchers say.
Knowing where such ancient bodies of water were located helps archaeologists understand the kind of environment encountered by Homo sapiens migrating out of Africa, study leader Ted Maxwell, a geologist at the Smithsonian National Air and Space Museum in Washington, said.
"You realize that hey, this place was full of really large lakes when people were wandering into the rest of the world," he said.
Desert winds have eroded and sands have buried much of the region's landscape, said Maxine Kleindienst, an anthropologist at the University of Toronto, but planned field studies will search for ancient shorelines suggested by the radar images.
Today Egyptians rely almost exclusively on the Nile and its annual floods for their water.
The ancient lakes, Maxwell said, suggest that such flooding was already a fixture a quarter million years ago.
