Impact cratering is now recognized as a major geological process on Earth. In particular, giant impacts had a fundamental influence on the geological and biological evolution of our planet with possible climatic effects. There are more than 160 confirmed impact craters on Earth, among which 17 are located in Africa, but it is estimated that only 10% of impact craters larger than 10km and younger than 100Ma are known. The Sahara is a particularly favorable region to host young impact craters, but according to cratering rate estimates, most of them still remain to be discovered, hidden under dry sandy sediments. Only four confirmed impact craters are currently known in eastern Sahara. Two are located in eastern Libya: B.P. (British Petroleum) structure and Oasis crater, and two are located in northern Chad: Aorounga and Gweni-Fada craters. While optical sensors can only image the desert's surface, it was shown twenty years ago that orbital Synthetic Aperture Radar (SAR) could retrieve subsurface information hidden under a few meters of dry sand.

Within an international project -- dubbed SAHARASAR -- that aims at mapping the near subsurface of the Sahara and Arabian regions using satellite-borne radar, the team produced a regional-scale radar mosaic at 100m resolution over the eastern Sahara from existing JERS-1 archives (a Japaneese satellite operated from 1990 to 1998). This unique data set allowed us to discover a double circular structure in the southeastern part of the Libyan desert. Fieldwork confirmed that this formation is an unknown double impact crater with a diameter around 10 km.


View: Full Article | Source: Space Daily