Among the list of hottest places on Earth, the Sahara desert in Mauritania near Ouadane, Africa definitely figures in the lineup, where temperatures can reach as high as 57.7 degrees Celsius. Harsh and hot winds ravage the extensive area throughout the year but there is also a mystery place in the desert, and worldwide people call it “The Eye of the Sahara.”
The Eye of the Sahara – The Richat Structure
The Richat Structure, or more commonly known as The Eye of the Sahara, is a geologic dome containing rocks that predate the appearance of life on Earth. The Eye resembles a blue bullseye and is located in Western Sahara. Geologists believe that the Eye’s formation began when the supercontinent Pangaea started to pull apart.
Discovery of The Eye of the Sahara
For centuries, only a few local nomadic tribes knew about the formation. It was first photographed in the 1960s by the Project Gemini astronauts, who used it as a landmark to track the progress of their landing sequences. Later, the Landsat satellite took additional images and provided information about the size, height, and extent of the formation.
Geologists originally believed that the Eye of the Sahara was an impact crater, created when an object from space slammed into the surface. However, lengthy studies of the rocks inside the structure show that its origins are entirely Earth-based.
Mystery behind the origin of The Eye of the Sahara
The Richat Structure was first described in the 1930s to 1940s, as Richât Crater or Richât buttonhole. In 1948, Richard-Molard considered it to be the result of a laccolithic thrust. Later its origin was briefly considered as an impact structure. But a closer study in the 1950s to 1960s suggested that it was formed by terrestrial processes.
However, after extensive field and laboratory studies in the 1960s, no credible evidence has been found for shock metamorphism or any type of deformation indicative of a hypervelocity e̳x̳t̳r̳a̳t̳e̳r̳r̳e̳s̳t̳r̳i̳a̳l̳ impact.
While coesite, a form of silicon dioxide considered as an indicator of shock metamorphism, had initially been reported as being present in rock samples collected from the Richat Structure, further analysis of rock samples concluded that barite had been misidentified as coesite.
Work on dating the structure was done in the 1990s. Renewed study of the formation of the Richat Structure by Matton et al in 2005 and Matton in 2008 confirmed the conclusion that it is not an impact structure.
A 2011 multi-analytical study on the Richat megabreccias concluded that carbonates within the silica-rich megabreccias were created by low-temperature hydrothermal waters, and that the structure requires special protection and further investigation of its origin.
A convincing theory of origin of The Eye of the Sahara
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.
Molten rock pushed up toward the surface but didn’t make it all the way, creating a dome of rock layers, like a very large pimple. This also created fault lines circling and crossing the Eye. The molten rock also dissolved limestone near the center of the Eye, which collapsed to form a special type of rock called breccia.
A little after 100 million years ago, the Eye erupted violently. That collapsed the bubble partway, and erosion did the rest of the work to create the Eye of the Sahara that we know today. The rings are made of different types of rock that erode at different speeds. The paler circle near the center of the Eye is volcanic rock created during that explosion.
The Eye of the Sahara – a landmark from space
Modern astronauts are fond of the Eye because so much of the Sahara Desert is an unbroken sea of sand. The blue Eye is one of the few breaks in the monotony that is visible from space, and now it’s become a key landmark for them.
The Eye of the Sahara is a great place to visit
Western Sahara no longer has the temperate conditions that existed during the Eye’s formation. However, it is still possible to visit the dry, sandy desert that the Eye of the Sahara calls home—but it’s not a luxurious trip. Travellers must first gain access to a Mauritanian visa and find a local sponsor.
Once admitted, tourists are advised to make local travel arrangements. Some entrepreneurs offer airplane rides or hot air balloon trips over the Eye, giving visitors a bird’s-eye view. The Eye is located near the town of Ouadane, which is a car ride away from the structure, and there is even a hotel inside the Eye.