Study: African drought changed history

The researchers, led by Professor Christopher Scholz of the school's earth sciences department, found sediments drilled from the beds of Lakes Malawi and Tanganyika in East Africa and from Lake Bosumtwi in Ghana contained evidence of a prolonged drought, the BBC reported.

Scholz said it's possible the drought was the reason some of the first humans left Africa and, subsequently, populated the Earth.

The sediment cores indicate that prior to 75,000 years ago, Lake Malawi, currently an inland sea some 340 miles long and about 2,300 feet deep, was reduced to a couple of pools no more than six miles across and about 655 feet deep.

Lake Bosumtwi, currently a 6-mile-wide lake that fills an old impact crater, lost all of its water.

The scientists said only a prolonged, continent-wide drought could have produced such an effect.

Scholz detailed the study this week in San Francisco, during the fall meeting of the American Geophysical Union.

Copyright 2005 by United Press International