Egyptian Impact Site: Possible Source of Libyan Desert Glass Discovered

Since 1932, scientists have been picking up yellow-green glass in a 60-by-100-kilometer (35-by-60-mile) area of the desert of southern Egypt near the Libyan border.Study of the glass has revealed the unmistakable isotopic signature of an asteroid impact, but the source crater has never been found -- until now.

El-Baz says that the crater he discovered is 30 kilometers in diameter, large enough to be the source of the glass. The crater is located in the Gilf Kebir plateau, an area previously identified by researcher Philippe Paillou of the Observatoire Aquitain des Sciences de L'Univers to be the largest impact crater field on Earth. The extreme conditions of the Sahara desert act to preserve impact crater structures, though the crater that El-Baz discovered and named "Kebira" (an Arabic word meaning "great" or "powerful") was difficult to see because of its large size and dissection by ancient rivers during a time when the region was wetter than it is now.