They unravel the origin of the impressive circular structure that opens in the middle of the desert, in the southeast of the Canary Islands
The Eye of the Sahara, also known as the Richat Structure, is a large circular geological formation in the middle of the desert., already in Mauritania, but not far from the Canary Islands. has nothing less than 50 kilometers in diameter and it is believed that it was formed by erosion and uplift, which gave rise to a kind of dome that was later eroded.
Although at first glance it looks like an impact crater (that is, caused by a meteor hitting the ground), it is more of an example of a geological structure called a symmetrical anticline, a type of fold in rock layers that has been exposed by geological processes and erosion.
It is one of the most incredible geological formations on the planet. In this Google Earth link it can be seen in all its magnitude.
It is certainly a spectacular place to be seen on the ground and also from a bird’s eye view, but it has also been thoroughly studied by geologists to understand exactly how this phenomenon originated.
The Eye of the Sahara is located in a fairly remote and secluded area of this desert, little frequented by scientists. That is why this formation did not receive much attention until some astronauts, who observed it from space (where its configuration is best appreciated) drew attention to its existencefrom which it became one of the most famous natural curiosities on the planet.
How was it formed?
The structure likely formed through a process called “folding,” creating what is called a symmetrical anticline. Folding occurs when tectonic forces acting from either side squeeze sedimentary rock.: If the rock is cold and brittle it can fracture, but if it is hot enough it will become a fold. Folds that form upwards are called anticlines, while folds downwards are called synclines.
However, in a 2014 article published in the Journal of African Earth Sciences, the researchers proposed a completely different formation explanation for the Eye of the Sahara. The authors believe that the presence of volcanic rock is evidence that molten rock was pushed to the surface, causing its dome shape, before eroding away to form the rings we see today. The article proposed that the breakup of the supercontinent Pangea might have influenced these volcanic formations and tectonic changes.
The structure is formed by a mixture of sedimentary and igneous rock. Erosion along the surface of the structure reveals fine-grained rhyolite and coarse crystalline gabbro rocks that have undergone hydrothermal alteration. The types of rocks found in the rings erode at different rates, creating different colored patterns on the surface.. Large, sharply angled chunks of sedimentary rock, called megabreccias, add to the colorful, swirling irregularities that make up the formation.
The Eye of the Sahara was selected as one of the first 100 geological heritage sites identified by the International Union of Geological Sciences (IUGS).
Reference study: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/33/8/665/103793/Resolving-the-Richat-enigma-Doming-and?redirectedFrom=fulltext
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