Saturday, October 16, 2021

THE EYE OF SAHARA

 The Richat Structure (21° 7.6 'N 11 o 24' W) is a unique geological structure located in the Sahara Desert in Mauritania.  The structure, which has a diameter of nearly 50 km, has attracted attention since the first space missions because it forms a rare bull's eye in the monotonous expanse of the desert.

 Decades ago it was considered to be the result of a meteorite impact due to its concentric circular shape, but after several studies it was shown that it is an anticline dome that has been eroded over millions of years and shows us its core.

 None of the studies carried out identified evidence of meteorological impact (impact metamorphism).

 The structure consists of rocks from the Proterozoic in the center of Ordovician on the outside, with carbonates (limestone and dolomites) containing siliceous breccias from the Cretaceous originated by karstic dissolution and collapse and intruded by annular dykes of basalt, kimberlite and alkaline volcanic rocks. and its breccia core are interpreted as the surface expression of an alkaline magmatic complex of Cretaceous age that affected the oldest rocks, giving rise to karstification and subsequent hydrothermal filling.

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