ESA image: Richat structure, Mauritania

May 2, 2014
Credit: JAXA/ESA

A giant, geological wonder in the Sahara Desert of Mauritania is pictured in this satellite image.

The 40 km-diameter circular Richat structure is one of the that is easier to observe from space than from down on the ground, and has been a familiar landmark to astronauts since the earliest missions.

Once thought to be the result of a , researchers now believe it was caused by a large dome of uplifting and, once at the surface, being shaped by wind and water into what we see today. Concentric bands of resistant quartzite rocks form ridges, with valleys of less-resistant rock between them.

The dark area on the left is part of the Adrar plateau of sedimentary rock standing some 200 m above the surrounding desert sands. A large area covered by sand dunes – called an erg – can be seen in the lower-right part of the image, and sand is encroaching into the structure's southern side.

Zooming in on the southern side of the bullseye, we can see individual trees and bushes as tiny dots. These follow a river-like structure that appears to have been dry when this image was acquired, a few weeks after the rainy season. Some areas to the south and east of the Richat appear to be covered with temporary lakes, which are dry for most of the year.

This image, also featured on the Earth from Space video programme, was acquired on 23 November 2010 by the Advanced Visible and Near Infrared Radiometer on Japan's ALOS satellite. 

Explore further: Sahara oasis from space

Related Stories

Sahara oasis from space

September 20, 2013

Deep in the Sahara Desert, the Al Jawf oasis in southeastern Libya is pictured in this image from Japan's ALOS satellite.

Space image: Kilimanjaro, Tanzania

January 24, 2014

This false-colour image from Japan's ALOS satellite was acquired over part of southern Kenya and the border with Tanzania.

Recommended for you

Horn of Africa drying ever faster as climate warms

October 9, 2015

The Horn of Africa has become increasingly arid in sync with the global and regional warming of the last century and at a rate unprecedented in the last 2,000 years, according to new research led by a University of Arizona ...

Could 'The Day After Tomorrow' happen?

October 9, 2015

A researcher from the University of Southampton has produced a scientific study of the climate scenario featured in the disaster movie 'The Day After Tomorrow'.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.