The geological mystery of Africa's eye that can only be seen from space

If you have the opportunity to travel Sara desert In the Mauritania region you can see the Eye of Africa, an area 50 kilometers in diameter that contains a series of rocky “waves” arranged in a circle. The geological mystery has spawned everything from conspiracy theories to numerous scientific hypotheses, but it remains without a final solution. Due to their size, they can only be partially appreciated from an airplane or, in all their glory, from space.

It is likely that its formation occurred through a process called… Geological foldcreating a symmetrical convex line — a kind of “bulge” of Earth's geological layers, with the latest at the top. The Eye of Africa was used by Project Gemini astronauts in 1965 as a reference point when it was discovered. Also called the Richat Structure, it was long thought to be an asteroid impact crater. This is far from the truth.

What formed the eye of the desert?

Geological dates It indicates that the sedimentary rocks of the structure's central dome date back to the end of the Proterozoic era, the second oldest era on the planet, between one billion and 542 million years ago. There are those who believe that the rocky remains, due to their circular shape, would be the ruins of the lost Atlantis, which is how Plato described the continent, but there is no evidence for this.

For the Rishat Structure to be created by a geological fold, tectonic forces must act from one side, compressing the sedimentary rocks – when the rocks are cold, they break, but if they are hot enough, they bend. A proposal published in a scientific journal Journal of African Earth Sciences But in 2014, I proposed something completely different.

In the study, scientists from the University of Quebec noticed the presence of… Volcanic rocksWhich may be evidence of molten metals being released to the surface, taking the shape of a dome. After hardening, the structure would have eroded until only the rock rings we see today remained. The researchers also suggested that The breakup of the supercontinent Pangea It would have helped form the volcanoes and tectonic changes responsible for this phenomenon.

The Eye of Africa consists of a mixture of sedimentary and igneous rocks, and its surface consists of fine rhyolite and coarse crystalline gabbro, modified by hydrothermal activity. Along the rings, minerals were found that had eroded at different speeds, leaving very different colored patterns throughout the structure. Sharp, sharp pieces of coarse-grained sedimentary rock help further color the site.

The center of the dome contains a layer of limestone and dolomite, with cavities up to 1 km in diameter, ring dikes and alkaline volcanic rocks. Since geologists discovered the Richat Structure, unraveling the mystery of its appearance has been a challenge, with no explanation that satisfies science. In 2022, it became one of the first 100 geological heritage sites recognized by the International Union of Geological Sciences (IUGS).

source: Journal of African Earth Sciences, International Union of Geological Sciences, geology, ZME Sciences

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