This astonishing image captured from space depicts the Eye of the Sahara, a 50-kilometer geological formation in the Sahara Desert of Mauritania, Africa. What the hell is it and why is it staring into space?
Also known as the Richat Structure, the Eye dates back to the Neoproterozic period, between 1 billion and 542 million years ago. Scientists long thought it to be a huge crater caused by a meteor impact. Others insist that it's the remnants of Atlantis. Turns out, it's neither.
From IFL Science:
The structure is likely to have actually formed through a process called "folding", creating what's 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's warm enough, it will become a fold. Folds that form upwards are called an anticline, while downward folds are called a syncline.
However, in a 2014 paper published in the Journal of African Earth Sciences, researchers proposed an entirely different formation explanation for the Eye. The presence of volcanic rock is said to suggest evidence of molten rock being pushed to the surface, causing the dome shape, before being eroded into the rings we see today. The paper proposed the separation of the supercontinent Pangaea may have played a part in these volcanic formations and tectonic shifts.
(via Daily Grail)