The Blue Eye of Sahara Desert: A geographical wonder
If you ever find yourself in space, you could see a massive eye looking back at you from Earth, the Blue Eye of the Sahara! The Blue Eye of the Sahara is a geological feature in the Sahara Desert of Africa that resembles a gigantic blue bullseye. Do you want to know how big it is? This rock structure has a diameter of 45 kilometres and is found in the nation of Mauritania, Africa. It is made up of rocks that are at least 100 million years old, with some going back to the time when there was no existence of life on Earth! For centuries, the Blue Eye of the Sahara was hidden from the world and only a few nomadic tribes in the local area knew about this structure. It was photographed for the first time by the Gemini (NASA's second human spaceflight programme) astronauts in the 1960s, who used it as a landmark to measure the progress of their landing procedures. Later, the Landsat 7 satellite (launched by NASA and the U.S. Geological Survey in 1999) captured more pictures that provided details on the formation's size, height and length. Let us explore the Blue Eye of the Desert, a unique geological formation!
What is the Blue Eye made up of?
Geologists believe that this circular geological structure is the result of a raised dome that has been eroded over years to reveal the formerly flat rock layer. When viewed from above, this formation seems to be in the form of concentric rings of rock layers with a centre that is referred to as the ‘bullseye.’ According to geologists, rocks exposed in the centre of the ‘bullseye’ are older than rocks creating the outside rings. Are there any specific kinds of rocks that make up the rock layers? These rocks contain igneous (volcanic) deposits as well as sedimentary deposits created when layers of dust are pushed aside by the wind and water deposits of sand and mud. Nowadays geologists can find many igneous rocks in the area of the eye such as kimberlite, carbonatites, black basalts and rhyolites. The Blue Eye of the Sahara was formerly thought to be an impact crater (a large hole in the ground), formed by a spacecraft that crashed onto the Earth. But long-term investigations of rocks inside the structure, demonstrate that its origins are wholly Earth-based.
How Was the ‘Eye’ Formed?
Millions of years ago these areas were not deserts as we know them today. They were probably much more temperate (moderate climatic conditions) and had plenty of water. During this temperate period, layered sandstone rocks were deposited by blowing winds along the bottoms of lakes and rivers. Then due to volcanic eruptions deep beneath the Earth's surface, the whole region around the Eye was lifted. The sandstone and other rocks that were at the bottom of the rivers were forced up by the underlying volcanic flow. Eventually, after the volcanoes cooled, the domed rock layers started to erode due to wind and water. The area began to settle and collapse within itself, resulting in the roughly round ‘eye’ feature!
The Blue Eye may vanish in the future
The Eye of the Sahara fascinates both tourists and geologists who come to study its unique geological features. However, as the region receives very little rainfall and is in a sparsely populated part of the desert, humans do not pose a significant threat to the Blue Eye! However, the Eye is vulnerable to environmental elements. The landscape is in danger due to erosion, just like everywhere else on Earth. But why are we predicting that it could vanish? Well, climate change is causing more desertification in the area. So, desert winds may create additional dunes (sandy hills) by bringing in more sand. It is possible that the Ble Eye of the Sahara Desert may be covered with sand and dust in the distant future. Therefore, future visitors may only see a windswept desert that is hiding one of the world's most spectacular geological features.