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The Copernicus Sentinel-2 mission captures a spectacular geological wonder in the Sahara Desert of Mauritania: the Richat Structure.<\/p>\n
This giant feature looks out from a sea of golden sand in the Adrar Region of northern Mauritania. Once thought to be the site of a meteor impact, the Richat Structure is now believed to have been caused by a process of uplift of a large dome of molten rock that, once at the surface, was shaped by wind, sand and water erosion. Geologists agree that the structure is at least 100 million years old.\u00a0<\/p>\n
The layered formation consists of a series of concentric rings and resembles a bull\u2019s eye from space, so is also known as the eye of the Sahara or the eye of Africa.<\/p>\n
The Richat Structure, 50 km in diameter, is easier to observe from space than from the ground, and has been a familiar landmark for astronauts since the earliest manned missions.<\/p>\n
In this comparison, we can see two views captured in September 2025: the image on the left is in natural colour, while the image on the right is a false-colour combination which highlights specific features.<\/p>\n
This remarkable formation exposes layers of sedimentary rock in different places, depending on the rates of erosion on the varying rock types. This can be better appreciated in the false-colour image. The more erosion-resistant quartzite sandstones appear in shades of red and pink and form the outer rings and high ridges internally, with valleys of less-resistant rock between them visible as darker areas. The central rings of the eye are about 80 m tall, with rocks older than those forming the outer rings.<\/p>\n
In the image on the left, the dark area surrounding the eye is part of the Adrar plateau of sedimentary rock standing some 200 m above the surrounding desert sands, which in turn are part of the Erg Ouarane, an immense sand expanse stretching hundreds of kilometres to Mali.<\/p>\n
Sand is also clearly visible encroaching into the structure\u2019s southern side. Here, individual trees and bushes can be spotted as tiny dots, which are visible in purple in the false-colour image, following a dry riverbed structure.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n