Richat Structure
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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, it 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.[1]
Original entry was from the NASA Earth Observatory; [1]
References
Further reading
- Guillaume Matton, Michel Jébrak and James K.W. Lee (2005). "Resolving the Richat enigma: Doming and hydrothermal karstification above an alkaline complex". Geology. 33 (8): 665–668. doi:10.1130/G21542.1.
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