A Mysterious Richat Structure at Sahara Desert
There is a distinguished circular or elliptical in Sahara Desert. It is often known as Richat structure. The Richat Structure is also known as the Eye of the Sahara and Guelb er Richat. Richat Structure is located in Sahara Desert near Ouadane, west–central Mauritania. The structure has a slightly elliptical in look and has 40 km n diameter dome (a rounded vault forming the roof of a building or structure, typically with a circular base. A dome is a feature in structural geology consisting of symmetrical anticlines that intersect each other at their respective apices.).
How this structure is formed?
The structure is mostly in elliptical in shape or in circular. But if we look such structure from West then it seems the same structure like human eye. The Richat structure was formed by a volcanic eruption. It also seems that by a lack of dome of igneous or volcanic rock. 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 center of structure is consists of a siliceous breccia covering an area that is at least 3 km in diameter. We can find different types of inheritor variety in this structure i.e. intrusive and extrusive igneous rocks. They also include different types of rocks (mostly Rhyolitic volcanic), Carbonatites and gabbros. The Rhyolitic volcanic rock contains mostly lava flow. The inner circle of Ricaht structure is dike about 20 in width and lies about 3 km from the center. We find many dikes (about 30) in Richat structure. The dike consists of carbonatites (type of rock). According some legend this carbonatites was cooled 100 million years ago. So defiantly this structure took millions of years to form. And it take many of erosion.
The fact of the rings which are equidistant to the center is still remains mystery. How can it form like that? How all rigs are arranging parallel to each other? This structure is formed 100 million years ago. So, obviously, this geological layer is uplifted. At this stage new questions arise. If we reassemble compare Ricaht Structure to the Atlantis (A fictional island or a likely mythical island nation mentioned in Plato’s dialogues “Timaeus” and “Critias”) by Plato then it completely matches with it. Atlantis main Island according to the text of Plato in Timaeus & Critias written in 360 BC. According to Plato, the island was divided into concentric circles of water and land. Island contains 2 of land and 3 of water. And Island also in a circular shape. We know also that 40000 years ago it existed huge lakes in Sahara. According to some legend the Atlantis was sunk by a gigantic earthquake and the whole island sunk in ocean. The meaning of Atlantis in Greek is Nesos: the island of Atlas. It is easier to get results there because the “eye” suffered a lot of collapsing and geologic changes that is making discoveries difficult. For the moment geological data are saying: “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 carbonate dikes (approximately) and sills have been mapped within the Richat structure.”
This prominent circular feature in the Sahara desert of Mauritania has attracted attention since the earliest space. Eye-catching hydrothermal features are a part of the Richat Structure. They include the extensive hydrothermal alteration of Rhyolites and gabbros and a central megabreccia. This megabreccia created by hydrothermal dissolution. The siliceous megabreccia is at least 40 m thick and its center to only a few meters thick along its edges. This breccia was created about 100 million years ago (using the 40Ar/39Ar method). This breccia was created by hydrothermal alteration.
Why the Richat Structure is nearly circular remains a mystery. Sahara desert covering ten countries of Africa with 9,400,000 square kilometers was 100 Millions of years ago all covered by sea. So in any case this is researches that deserve a lot of attention.