NASA Photo of Sahara: Richat Structure, Mauritania

NASA

Richat Structure, Mauritania, Western Sahara Desert

“Richat Structure, Mauritania

This prominent circular feature in the Sahara desert of Mauritania 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 fossil in the desert, the structure, which has a diameter of almost 30 miles, has become a landmark for shuttle crews. Initially interpreted as a meteorite impact structure because of its high degree of circularity, it is now thought to be merely a symmetrical uplift that has been laid bare by erosion. Paleozoic quartzites form the resistant beds outlining the structure.”

Image Credit: NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

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4 Responses

  1. It might be a great question to put to the Bad Astronomer, Phil Plait, @ his website, Bad Astronomy.

    To me, it looks more like an ancient impact crater.

  2. Whether it is an impact crater or an uplift can be easily answered by looking at the geology. An uplift will show layers exposed in a particular order, with the lower layers towards the center and the higher ones at the periphery. An impact crater would have a very different profile and in particular should have shocked rocks near the center. I’m pretty sure that the geologists have looked closely at this, so one would have to go with their conclusion, which would be the uplift and not the impact crater.

    I’m an astronomer, by the way. I’ve met Phil at astronomical meetings. He’s good.

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