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Communications Specialist

Laura Faye Tenenbaum is a science communicator at NASA's Jet Propulsion Laboratory and teaches oceanography at Glendale Community College.

Pick of the pics
Jewel in the desert
November 18, 2010
posted by Dr. Amber Jenkins
16:00 PST
Pick of the pics

Credit: NASA/GSFC/METI/ERSDAC/JAROS and the U.S./Japan ASTER Science Team. Caption adapted from the ASTER gallery.

This image of the Richat Structure, Oudane, Mauritania, taken by the NASA/Japan ASTER instrument on October 7, 2000, is a landmark for space shuttle crews. It shows a prominent circular feature in the Sahara desert of Mauritania, something that 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 feature, which has a diameter of almost 50 kilometers or 30 miles, was initially interpreted as a meteorite impact site because of its high degree of circularity. However, now it is thought to be merely the result of geological processes — a symmetrical uplift of tectonic plates that increased the elevation of the land, which has since been laid bare by erosion. The structure is outlined by beds of ancient quartzite (sandstone-derived rock) from the Paleozoic era about 250 to 550 million years ago. The image you see covers an area of 45 x 47 kilometers.

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