The Eye of the Sahara, when viewed from above, looks like a massive impact crater sitting in the middle of the Sahara Desert in Mauritania. This crater-like anomaly, 50 kilometers in diameter and composed of a series of regular wavelets, is actually a purely terrestrial phenomenon.
This magnificent ancient geological formation was used as a directional sign by Gemini astronauts in the 1960s. Geologists originally believed that the Eye of the Sahara, also known as the Richat Structure, was an enormous impact crater. However, further research on the sedimentary rock that formed the central dome dates the formation to the late Proterozoic, between 1 billion and 542 million years ago.
We should also point out that because its circular shape resembles the land described by Plato, some believe this entity is actually the remains of the lost city of Atlantis.
It is thought that this formation actually emerged through a process called “folding”, which creates the phenomenon known as symmetric anticline. Folding occurs when tectonic forces acting from both sides compress the sedimentary rock. If the rock is cold and flimsy it can break, but if it’s hot enough it will bend. Upward folds are called anticline, and downward folds are called syncline.
However, in a 2014 paper published in the Journal of African Earth Sciences, researchers proposed an entirely different formation explanation for the Eye of the Sahara. The presence of volcanic rock has allegedly provided evidence that molten rock was pushed to the surface before eroding into the rings we see today, causing the dome shape. The article suggested that the splitting of the supercontinent Pangea may have played a role in these volcanic formations and tectonic shifts.
This structure consists of a mixture of sedimentary and igneous rock. Erosion at the surface of the structure revealed hydrothermally altered fine-grained rhyolite and coarse-crystalline gabbro rocks. The types of rocks found in the rings erode at different rates, creating different colored patterns across the surface. Large sharp-angled pieces of sedimentary rock called megabreccia contribute to the swirling colored irregularities that make up the formation.
The center of the dome contains a kilometer-wide limestone-dolomite layer with breccia, annular channels and alkaline volcanic rock. The Eye’s complex geology has puzzled and intrigued geologists since its discovery, and is still widely regarded as one of the world’s most impressive geological features. That’s why it was selected as one of the top 100 geological heritage sites recognized by the International Union of Geological Sciences (IUGS) in 2022.
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