In the Mauritanian part of the Sahara Desert, east of the village of Ouadan, inside the Taudeni syneclise, there is a mysterious geological formation called the Richat structure (Guell Er-Richat, also known as the Eye of the Sahara). These unusual circles among the monotony of the desert attract many inquisitive travelers.
For quite a long time, the Rishat structure served as a reference point for astronauts in orbit, as it represented a well-visible object in the vast expanse of an unremarkable desert.
Satellite photo of the Richat structure. The photo is based on the effect of thermal emission and was taken with the ASTER radiometer on October 7, 2000.
Topographic reconstruction (scaled 6: 1 on the vertical axis) from satellite photos. The colors represent: bedrock = brown, sand = yellow / white, vegetation = green, sediment = blue.
The diameter of the structure is 50 km. With such an impressive scale, this mysterious structure can only be found at a considerable height. Therefore, the Eye of the Sahara was discovered only in 1965 with the beginning of space technology flights into the Earth's orbit. Since then, the Richat structure has served as a clear reference point for astronauts in orbit, and scientists have been puzzling over the nature of this unusual formation.
It is believed that Rishat was formed in the period between the late Proterozoic and the Ordovician (the most ancient ring is about 500 - 600 million years old). Previously, it was assumed that the ring structure is an impact crater, but this hypothesis is not consistent with the flat bottom shape and the complete absence of rocks with traces of impact. The formation of the structure as a result of a volcanic eruption is also highly unlikely due to the absence of a dome of igneous or volcanic rocks.
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Modern scientists believe that sedimentary rocks of the Richat structure are the result of erosion on the uplift of a section of the earth's crust. To date, this version is the most plausible.
Other versions: the place where the meteorite fell, the mouth of an extinct volcano, the place of landing of aliens. Nobody can prove these versions.
Traces indicating the fall of the meteorite, and the impact itself and its consequences were never found. In the center of the formation, there was also no deepening corresponding to the force of the impact, similar to the depressions in the places of the fall of cosmic bodies. It also failed to explain the presence of not one, but several rings, ideally nested within each other. To do this, several meteorites had to fall into this place with perfect accuracy, which is unlikely.
According to the volcanic version, the origin of the Mauritanian ring structures is explained by the centuries-old erosion of the volcano, under the influence of which an unusual geological artifact was formed.
However, according to the conclusion of specialists in the field of geology, the Richat structure cannot be the result of a volcanic eruption, since sedimentary dolomite rocks predominate in its formation and volcanics, characterized by microscopic sizes of mineral crystals, and effusive rocks are completely absent. In addition, in the central part of the structure, geologists have not been able to find at least some signs of a volcanic dome.
Quite fantastic versions, including the landing of aliens, did not withstand the test of elementary common sense.
Supporters of the supernatural, who tried to explain the presence of circles by the presence of otherworldly forces, also faced a fiasco: there are no anomalies in the area of the structure at all - shepherds have long lived on the mysterious territory and camels graze peacefully without showing the slightest signs of concern.