Mauritania and Western Sahara

What appears to be dramatic plumes of pale orange dust streaming across Mauritania and southern Morocco's Western Sahara is actually a permanent feature caused by wind erosion. This part of Mauritania is dominated by low-lying rocky desert, with a large sandstone plateau rising in the east. At the lower right corner of the image is a circular feature called the Richat Structure. It's almost perfectly-round shape resembles an impact crater (such as by a meteorite), but in all likelihood is merely a symmetrical uplift (circular anticline) that has been laid bare by erosion. This is a true-color Terra MODIS image from December 10, 2004 produced as a subset image by the MODIS Rapid Response System.