Scientists have discovered a
31 kilometre diameter crater in the Saharan desert.The newfound crater was created by an impact of an asteroid roughly 1.2 kilometres wide. As yet the exact date of when it occurred has not been determined.
The crater was discovered in satellite images by Boston University researchers Farouk El-Baz and Eman Ghoneim. The crater has two rings, and two river beds cut through the formation.
(10000 years ago, Gilf Kebir hosted a much wetter climate than today)
Source
Discovery of the largest impact crater field on Earth in the Gilf Kebir region, Egypt (
Ed -actually there is one bigger)
Philippe Paillou a,*, Ahmed El Barkooky b, Aly Barakat c, Jean-Marie Malezieux d,
Bruno Reynard e, Jean Dejax f, Essam Heggy g
Abstract
Using orbital imaging radar, we have detected a large number of circular structures in the southwestern Egyptian desert, covering more than 4500 km2 close to the Gilf Kebir plateau in sandstones of Upper Cretaceous. Fieldwork confirmed that it is a new impact crater field: 13 craters from 20 m to 1 km in diameter were studied. The impact origin is confirmed by the observation of shock-related structures, such as shatter cones and planar fractures in quartz grains of breccia. Considering the extension of the crater field, it was possibly created by several meteorites that broke up when entering the atmosphere.
The area extends over 75 km × 60 km, between latitudes 23.10deg N–23.40 deg. N and longitude 26.50 deg E–27.35 deg E.
Read more (PDF)
Another view... (volcanic)
http://www.tlc-exped.net/LDSG.html (Libyan Desert Silica Glass used as tools 130.000 - 40.000 years ago)