Scientists are Still Mystified by the Eye of the Sahara - AKA The Richat Structure in Mauritania

Astrogeology, Asteroids, Robots, Space Flight & Extraterrestrial Matters

Date posted: 07/19/16

Meghan Bartels reports that for millennia, the Eye of the Sahara was hiding in plain sight. That is because this huge and mysterious geologic formation is hard to spot from ground level, walking around on Earth. It turns out that geoscientists only really discovered this incredible bullseye in the sand when humans went into orbit. But even now we have found it, geoscientists have different views on its origin. The Eye of the Sahara, which is more formally known as the Richat structure, is located in the western Sahara Desert in Mauritania. On the ground, it is about 25 miles across. They were particularly asked to look out for any large circular features which might be the roots of impact structures, according to the text accompanying a set of photographs published from the mission. Impact craters are geologically important because they tell us about the history of the Earth. Also, knowing how many times space rocks have crashed into our planet can help scientists make some predictions about the future. And for a while, geoscientists did think that the Eye of the Sahara was an impact crater. But they did not find enough melted rock to make that hypothesis hold water. Current hypotheses suggest a much more complicated origin of this incredible natural formation. The main ring structure of the Eye appears to be the eroded remains of what was once a dome of layers of the Earth crust. But it could be the result of an airburst of an asteroid explosion coming in vertical to the surface. others posit that the Eye formation began more than 100 million years ago, as the supercontinent Pangaea was ripped apart by plate tectonics and what are now Africa and South America were being torn away from each other. Later, molten rock pushed up towards the surface but did not make it all the way, creating a dome of rock layers, like a very large pimple. This also created fault lines circling the Eye and crossing it. Then weathering and erosion took over. Read on...