Tenoumer is considered to be an impact crater in Mauritania. Details The crater is located in the western Sahara Desert. It is in diameter and its age is estimated to be 21,400 ± 9,700 years old. The crater is exposed at the surface and is nearly circular. Edges of the crater rise up to high above the base of the crater, but the bottom of the crater is covered with an approximately thick layer of sediments. Tenoumer crater has formed in gneiss and granite of Precambrian peneplain with a thin layer of Pliocene sediments (no older). The crater is believed to be caused by an impact event due to basement rocks found outside the crater. A volcanic origin was once theorized because of the discovery of basalt and rhyodacite outside of the crater basin, but current evidence clearly indicates an impact origin. References External links Nasa - Image of the Day February 17, 2008 Meteorite impact structures Additional Images of Tenoumer crater Impact craters of Mauritania Pleistocene impact craters