The Eye of the Sahara, also known as the Richat Structure, Guelb er Richat, and Eye of Africa, is a structure in the Sahara Desert that has an appearance similar to an eye.
The feature is circular with multiple concentric rings, a truly unusual appearance.
Why Is It Famous?
The unusual appearance of the Eye of the Sahara gives it its fame. Geologists know a reasonable amount of information about the structure, but there have still been questions within the past few years.
As the name implies, the Eye of the Sahara is in the Sahara Desert. It is in the Adrar Plateau, which is close to Ouadane, a city in west-central Mauritania.
This structure is a dome that is slightly elliptical and deeply eroded. At its largest, the diameter is 40 kilometers. The dome exposes a series of sedimentary rock, ranging from Ordovician sandstone by the edges to Late Proterozoic rock in the center.
The sedimentary rocks in the structure go outwards at an angle between 10 and 20 degrees. Thanks to differential erosion of the quartzite’s resistant layers, there are circular cuestas in high relief. The center of the structure is a siliceous breccia over a 30-kilometer (or larger) area.
The Eye of the Sahara is of great interest to geologists due to the range of extrusive and intrusive igneous rocks in the center. These include kimberlites, carbonatites, gabbros, and rhyolitic volcanic rocks.
Those rhyolitic rocks include tuffaceous rocks that experienced hydrothermal alteration as well as lava flows. The Richat Structure also features amazing hydrothermal features, such as hydrothermal alteration of gabbros and rhyolites.
Events in Time
The first description of the Eye of Sahara was during the 1940s, with the name of the Richat Crater. The efforts to date the structure took place during the 1990s, with further efforts more recently.
The unique eye-like appearance, size, and range of rocks within the Eye of the Sahara make it a favorite landmark of geologists and tourists alike.