Anti-Atlas Mountains, Morocco

This astronaut photograph was taken in December 2001 by the crew of Space Shuttle mission 108 using a Hasselblad camera with 250-mm lens. The Anti-Atlas Mountains of northern Africa and the nearby Atlas mountains were created by the prolonged collision of the African and Eurasian tectonic plates, beginning about 80 million years ago. Massive sandstone and limestone layers have been crumpled and uplifted more than 4,000 meters in the High Atlas and to lower elevations in the Anti-Atlas. Between more continuous major fold structures, such as the Jbel Ouarkziz in the southwestern Anti-Atlas, tighter secondary folds have developed.  The broad, open style of folds seen in this view is common where evaporites are involved in the deformation; sea sands, clays, limey sediments, and evaporite layers (gypsum, rock salt) were deposited earlier in the precursors to the Mediterranean and the Atlantic Ocean. During the mountain-building plate collision, the gypsum layers flowed under the pressure and provided a slippery surface on which overlying rigid rocks could glide.