Richat Structure, also known as the Eye of the Sahara or blue eye of Africa, is a prominent geological circular feature in the Sahara desert in Mauritania near Ouadane. It is nearly 50 kilometres across and very visible from space. Initially interpreted as an asteroid impact structure because of its high degree of circularity, and then as a structure formed by a volcanic eruption that also seems improbable because of the lack of a dome of igneous or volcanic rock, it is now argued to be a highly symmetrical and deeply eroded geologic dome that collapsed.

So it is now thought by many to have been caused by uplifted rock sculpted by erosion. But the fact that the “rings”, are equidistant to the centre and that the Richat Structure is nearly circular remains a mystery.

The Richat Structure contains more than 32 carbonatite dykes which are 1 to 4 meters wide and 300 meters long. According to researchers, the carbonatite rocks in the Richat Structure date back to 104 million years ago. In the northern part of the Giant Eye, scientists have found kimberlitic plug that is believed to be 99 million years old. Aside from rocks, hydrothermal features are also part of the Giant Eye in the Sahara desert.

When it was first discovered, the Giant Eye of Africa was considered an asteroid impact structure. The reasoning behind the theory is that the high degree of circularity could be a result of an asteroid impact.

However, nowadays, scientists argue that the feature it is symmetrical and deeply eroded geological dome. A recent study argues that the carbonates in the Richat Structure were created by hydrothermal waters with low temperature.

However, no matter what people believe, every scientist out there is certainly in one thing: the Giant Eye of Africa needs protection and requires a deeper and more analytical research of its origin. Scientists still have questions about the Eye of the Sahara, but two Canadian geologists have a working theory about its origins.

They think that the Eye’s 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. Modern astronauts are fond of the Eye because so much of the Sahara Desert is an unbroken sea of sand. The Eye is one of the few breaks in the monotony, and now it’s become a key landmark for them. NASA explained:

The Richat Structure in the Sahara Desert of Mauritania is easily visible from space because it is nearly 50 kilometers across. Once thought to be an impact crater, the Richat Structure’s flat middle and lack of shock-altered rock indicates otherwise. The possibility that the Richat Structure was formed by a volcanic eruption also seems improbable because of the lack of a dome of igneous or volcanic rock. Rather, the layered sedimentary rock of the Richat structure is now thought by many to have been caused by uplifted rock sculpted by erosion. The above image was captured last year by the orbiting Landsat 7 satellite. Why the Richat Structure is nearly circular remains a mystery.

Some people believe that the Eye of the Sahara is actually the remains of the city of Atlantis, which Plato described as concentric rings of water and land. But if you ask us, the geological history this formation reveals is way more interesting.