What is the Eye of Sahara? Know All About the Richat Structure

Deep within the western Sahara Desert in Mauritania, there is one of the world's natural wonders: the Eye of Sahara, or rather, the Richat Structure. Such a structure is immense and takes the shape of a circle, with an approximate diameter of 40 kilometers-about 25 miles. It is so huge it can be seen from space. Its striking concentric rings invite scientists, adventurers, and space travelers because of its appearance as a giant bullseye or eye.

What is the Richat Structure?

• The Richat Structure is a deeply eroded geological dome formed by the uplift of underground molten rock during the Cretaceous Period-a time from 145 to 66 million years ago.

• It is composed of concentric rings of sedimentary and igneous rocks exposed by millions of years of erosion.

• The structure is situated on the Adrar Plateau in northwestern Mauritania near the town of Ouadane.

Geological Formation and Features

• This dome was produced by a subsurface igneous intrusion deforming the overlying layers of sedimentary rock, so older layers are exposed at the center.

• The various rates of erosion of the rock layers, hard quartzites and igneous rocks versus softer sandstones and shales, created these distinct circular ridges called cuestas.

• This is a central area of siliceous breccia, about 30 km in diameter, with exposures of rhyolites, gabbros, carbonatites, and kimberlites inside it.

• Faults and fractures observed around the structure indicate the shifting of layers of rock during the formation process.

Misconceptions and Theories

• The Eye of Sahara was initially believed by many to be an impact crater from a meteorite because of its apparent circular shape, but scientific surveys found no evidence of impact rocks or shocked minerals.

• Due to its circular design and mythological parallels, some researchers in the 1960s speculated about links to the fabled lost city of Atlantis; geological studies have disproven this.

• The most widely accepted explanation today is that the structure represents a natural result of geological uplift and erosion over millions of years.

Archaeological Significance

• The site has yielded significant archaeological findings, including Acheulean Paleolithic stone tools from over one million years ago, showing early human occupation.

• These discoveries provide evidence of prehistoric human life and its migration patterns across the fluctuating climates of the Sahara.

Importance in Modern Science and Exploration

• The Richat Structure is recognized by the International Union of Geological Sciences as one of the 100 geological heritage sites of global scientific significance.

• It is even visible from space, serving as a well-known landmark for satellite orbiters and astronauts alike.

• Its unique geology supplies important information about the tectonic, volcanic, and erosional histories of Earth.

Why is the Eye of Sahara visible from space? 

Measuring 40km in diameter and composed of distinctive concentric rings, this structure stands out starkly against the desert landscape. 

What are the kinds of rocks that compose the Richat Structure? 

Rocks involve quartzite, sandstone, and limestone (sedimentary) and rhyolite, gabbro, carbonatite, and kimberlite in their igneous types shaped by erosion. 

Is Eye of Sahara the lost city of Atlantis? 

There is no scientific evidence to support this; it is a natural geological feature, though myths continue for popular intrigue. 

How old is the Richat Structure? 

It was formed in the Cretaceous period, between 94 and 104 million years ago, when volcanic activity raised the area. 

The Eye of Sahara or Richat Structure is an extraordinary example of the geological artistry of Earth, shaped by volcanic activity and sculpted by erosion over millions of years. More than its striking appearance, it holds clues to the geological past of Earth and early human evolution in the Sahara. This naturally formed wonder continues to inspire scientists and explorers alike-a source of mystery and grandeur that typifies Earth's dynamic landscapes.

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