Stock Photo: Richat Structure, Mauritania, True Colour Satellite Image. Richat Structure, Mauritania, true colour satellite image. The Richat structure is a geological formation in the Maur Adrar Desert in the African country of Mauritania. Although it resembles an impact crater, the Richat Structure formed when a volcanic dome hardened and gradually eroded, exposing the onion-like layers of rock. Image taken on 13 January 2003 using LANDSAT data.