Introduction
The Richat Structure, also known as the Eye of the Sahara and Guelb er Richat, is a prominent circular feature in the Sahara desert near Ouadane, west–central Mauritania. This structure is a deeply eroded, slightly elliptical, 40 km in diameter dome. The sedimentary rock exposed in this dome ranges in age from Late Proterozoic within the center of the dome to Ordovician sandstone around its edges. The sedimentary rocks comprising this structure dip outward at 10°–20°. Differential erosion of resistant layers of quartzite has created high-relief circular cuestas. Its center consists of a siliceous breccia covering an area that is at least 3 km in diameter.
Location:
About Sahara it has been known that it was wet, more precisely a shallow ocean, called the Triton Sea. You can read all about it by Herodotus, who we also know Plato had read. As well as the rock art found in the mountains of Tassili, some dated 5000 BC.
It was an ocean when sea levels rose and through Gabes the sea went over the Sahara, leaving the Atlas mountains exposed and some other high land, Tassili for one, as it fluctuated some areas were exposed as plains and then may have been covered again, this occurring until a climate change started drying out the Sahara. The sea went over the Sahara and came out where the land is at sea level, which happens to be the west coast of Mauritania. Look at an atlas, you can how this would be. Gabes is in Tunisia.
Geology:
The 'Eye of Africa', a geological phenomenon in the Sahara Desert of Mauritania, a country in northern Africa, peers up in this satellite image. Exposed within the interior of the Richat Structure are a variety of intrusive and extrusive igneous rocks. They include rhyolitic volcanic rocks, gabbros, carbonatites and kimberlites. The rhyolitic rocks consist of lava flows and hydrothermally altered tuffaceous rocks that are part of two distinct eruptive centers, which are interpreted to be the eroded remains of two maars. According to field mapping and aeromagnetic data, the gabbroic rocks form two concentric ring dikes. The inner ring dike is about 20 m in width and lies about 3 km from the center of Richat Structure. The outer ring dike is about 50 m in width and lies about 7 to 8 km from the center of this structure. Thirty-two carbonatite dikes and sills have been mapped within the Richat Structure. The dikes are generally about 300 m long and typically 1 to 4 m wide. They consist of massive carbonatites that are mostly devoid of vesicles.
History:
The carbonatite rocks have been dated as having cooled between 94 to 104 million years ago. A kimberlitic plug and several sills have been found within the northern part of the Richat Structure. The kimberlite plug has been dated being about 99 million years old. These intrusive igneous rocks are interpreted as indicating the presence of a large alkaline igneous intrusion that currently underlies the Richat Structure and created it by uplifting the overlying rock.
The Richat structure, as it is also known, resembles a bull's-eye peering out of the sand . The structure is 30 miles (50 kilometers) in diameter, large enough in the featureless Sahara that the earliest space missions used it as a landmark.
Erosions:
Different rates of erosion on the varying rock types have formed concentric ridges; the more erosion-resistant rocks form high ridges (blue and purple), while the non-resistant rocks form valleys (yellow).
A plateau of sedimentary rock forms the darker region surrounding the Richat structure. This plateau stands roughly 656 feet (200 meters) above the surrounding sand.
In addition to the eye, Mauritania's highest peak can be seen in this image. The Kediet ej Jill Mountain is a magnetic mountain standing almost 3,281 feet (1,000 m) high. It appears blue because it is composed entirely of magnetite, a natural magnetic substance.
Myths:
While the Eye of Africa may be staring into space from earth, we know that the eyes of God watch over the happenings on earth from heaven. Second Chronicles 16:9 tells us: “The eyes of the LORD range throughout the earth to strengthen those whose hearts are fully committed to him.”
When God looks down from heaven on you, will He find your heart fully committed to him? If you answer yes, it’s possible you're finding God in the Eye of Africa.
Because it is so symmetrically circular, it was first thought to be an impression from a meteorite strike. However scientists now believe the formation is a natural upheaval of the land revealed by erosion. According to the article accompanying the above photo, the Eye of Africa became a landmark for space shuttle crews.
Initially interpreted as an asteroid impact structure because of its high degree of circularity, it is now argued to be a highly symmetrical and deeply eroded geologic dome. Despite extensive field and laboratory studies, geologists have found a lack of any credible evidence for shock metamorphism or any type of deformation indicative of a hypervelocity extraterrestrial impact. While coesite, 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. In addition, the Richat Structure lacks the annular depression that characterizes large extraterrestrial impact structures of this size. Also, it is quite different from large extraterrestrial impact structures in that the sedimentary strata comprising this structure is remarkably intact and "orderly" and lacking in overturned, steeply dipping strata or disoriented blocks. A more recent 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.
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