Image from NASA Earth Observatory
The Ouarkziz Impact Crater lies in northwestern Algeria, close to the border with Morocco. The crater was formed by a meteor impact less than 70 million years ago. Originally called Tindouf (being ca. 170 km noth-east of the town of Tindouf), the 3.5-kilometer wide crater (image center) has been heavily eroded since its formation; however, its circular morphology is highlighted by exposures of older sedimentary rock layers that form roughly northwest to southeast-trending ridgelines.
The crater is set in carboniferous limestones and shales of Upper Visean and Lower Namurian formations which are upturned at the crater rim. The crater consists of three concentric zones. Outer zone with outward dipping faults. Inward dipping zone. Central brecciated vertical dipping beds. It is thus a complex crater.