The Richat Structure, a prominent circular feature in the Sahara desert of Mauritania near Ouadane, has attracted attention since the earliest space missions because it forms a conspicuous bull's-eye in an otherwise rather featureless expanse of desert. The structure, which has a diameter of almost 50 kilometers, was intially interpreted as a meteorite impact structure because of its high degree of circularity, but is now thought to be a symmetrical uplift that has been laid bare by erosion. The Richat Structure, a prominent circular feature in the Sahara desert of Mauritania near Ouadane, has attracted attention since the earliest space missions because it forms a conspicuous bull's-eye in the otherwise rather featureless expanse of the desert. Described by some as looking like an outsized ammonite in the desert, the structure, which has a diameter of almost 50 kilometres (30 miles), has become a landmark for space shuttle crews. Initially interpreted as a meteorite impact structure because of its high degree of circularity.
Iit is now thought to be a symmetrical uplift (circular anticline or dome) that has been laid bare by erosion. Paleozoic quartzites form the resistant beds outlining the structure. However, a line drawn 208° S-SW between the Temimichat impact crater and the Tenoumer impact crater, themselves separated by 166 kilometers, intersects the center of the Richat structure, 390 km away.
The Richat Structure in central Mauritania is a stunning geological structure 50 kilometers across (Wikipedia entry). Once thought to be an impact crater, it is actually a sedimentary formation that has eroded flat over many eons. Apparently there’s a hotel smack-bang in the middle of it. There are also several other similar structures in the Sahara, such as the Jebel Uwaynat (thumbnail #2) which was used to define the borders of Sudan, Egypt and Libya, and also the Brandberg Intrusion in Namibia. Even though none of these features are in high-resolution, it’s well worth zooming in a bit, as they’re perhaps even more fascinating to look at closer up.
