MULTIMEDIA
Geologic delight
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This beautiful image, taken on 11 January 2001, shows a geological formation in the Maur Adrar Desert in Mauritania, Africa. Known as the "Richat Structure," this snail-shell-like formation was created when a volcanic dome hardened and gradually eroded, exposing onion-like layers of rock.
Credit
Image taken by the Landsat-7 satellite. Source: NASA Goddard Photo and Video flickr photostream. Courtesy of NASA/U.S. Geological Survey/Landsat-7/Goddard Space Flight Center.