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A topographic reconstruction (scaled 6:1 on the vertical axis) from satellite photos. False coloring as follows: bedrock=brown, sand=yellow/white, vegetation=green, salty sediments=blue

Satellite picture of the Richat Structure

The Richat Structure is a prominent circular feature in the Sahara desert of Mauritania near Ouadane. It 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. The structure, which has a diameter of almost 50 kilometres (30 miles), has become a landmark for space shuttle crews.

This is believed to be a meteorite impact structure because of its high degree of circularity, however one thought is that it is a symmetrical uplift (circular anticline or dome) that has been laid bare by erosion. Paleozoic quartzites form the resistant beds outlining the structure.

[edit] References

• Original entry was from the NASA Earth Observatory http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=9319

[edit] Further reading

• Guillaume Matton, Michel Jébrak and James K.W. Lee (August 2005). "Resolving the Richat enigma: Doming and hydrothermal karstification above an alkaline complex". Geology 33 (8): 665–668. doi:10.1130/G21542.1. 

[edit] External links

Wikimedia Commons has media related to: Richat Structure

• NASA Earth Observatory page
• Astronomy Picture of the Day
• View satellite image in Google Maps
• Line of Muritanian desert craters

Coordinates: 21°7′29.67″N 11°24′12.96″W / 21.1249083°N 11.4036°W / 21.1249083; -11.4036

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