Netizens Astonished by the Mysterious Eye-Like Formation in the Sahara Desert Known as the Richat Structure

Nestled within the Sahara Desert lies a geological wonder known as the “Blue Eye of the Sahara” or, as it’s officially named, the Richat Structure. Spanning a vast 40-kilometer expanse in Mauritania, this enigmatic formation has left netizens baffled and intrigued.

First brought into the public eye by Gemini astronauts who used it as a landmark in the 1960s to monitor their space missions, the Richat Structure has since garnered worldwide attention. Subsequently, Landsat satellites captured additional images, providing invaluable insights into its size, height, and extent.

Initially believed by geologists to be a result of an impact from an extraterrestrial object, the Richat Structure’s origins have been a subject of fascination. However, extensive studies of the rocks within the structure have revealed their terrestrial nature. This light elliptical dome boasts a diameter of 40 kilometers (25 miles) and houses sedimentary rocks ranging from the Late Proterozoic in the center to Ordovician sandstone in the middle. The sedimentary rocks form this structure’s unique, eroded 10-20° puff-shaped concentric rings, with the center featuring a siliceous breccia covering an area of at least 30 kilometers (19 miles) in diameter.

Deep within the interior of the Richat Structure, one can find various intrusive and extrusive igneous rocks. These include rhyolitic volcanic rocks, gabbros, carbonatites, and kimberlites. The rhyolitic rocks comprise lava flows and hydrothermally altered tuffaceous rocks from two distinct eruptive centers, believed to be remnants of two maars. Gabbroic rocks, forming two concentric ring dikes, have been observed. Thirty-two carbonatite dikes and sills, typically 300 meters long and 1 to 4 meters wide, have been meticulously mapped. These carbonatite rocks, almost devoid of vesicles, have been dated to have cooled between 94 and 104 million years ago. The northern part of the Richat Structure houses a kimberlitic plug and several sills, with the kimberlite plug dating to around 99 million years old. These intrusive igneous rocks hint at the presence of a substantial alkaline igneous intrusion beneath the Richat Structure, responsible for uplifting the overlying rock layers and forming this remarkable geological feature.

Millions of years ago, volcanic activity beneath the Earth’s surface elevated the entire landscape surrounding the Eye of the Sahara. These regions, now deserts, were likely once much more temperate, featuring abundant flowing water. Layered sandstone rocks were deposited by blowing winds and at the bottoms of lakes and rivers during this temperate period. Subsurface volcanic flows eventually pushed up the overlying layers of sandstone and other rocks. After the volcanic activity subsided, wind and water erosion began eroding the domed rock layers. The region began settling and collapsing into itself, creating the roughly circular “eye” feature.

Today, the ancient rocks within the Eye of the Sahara have provided researchers with valuable information about its origins. Its formation is intricately tied to the gradual breakup of the supercontinent Pangaea, as the Atlantic Ocean waters began to flow into the region. As Pangaea separated, magma from deep within the Earth’s mantle pushed upwards, forming a circular rocky dome encircled by layers of sandstone. Erosion acted upon the igneous rocks and sandstones, and as the dome subsided, it left behind circular ridges, giving the Richat Structure its iconic circular shape. While the Eye no longer enjoys the temperate conditions that existed during its formation, it remains an intriguing testament to Earth’s geological history.

To witness this incredible formation today, visitors must embark on a journey to the arid, sandy desert it calls home. However, it’s not a straightforward trip. Travelers must secure a Mauritanian visa and find a local sponsor to gain access. Once admitted, tourists can make local travel arrangements, including airplane rides or hot air balloon trips over the Eye to experience it from a bird’s-eye view. The Eye is located near the town of Ouadane, a car ride away from the structure, and even boasts a hotel within its unique confines.