"Eye of the Sahara" in Northwest Africa
Today’s Image of the Day from NASA Earth Observatory features the Richat Structure and the extensive dune fields that surround it. The Richat Structure, also known as the Eye of the Sahara, is a geological feature in the Adrar Plateau of Northwest Africa.
“The origin of the Richat Structure was initially thought to be the result of an impact event because large meteors typically produce circular features on Earth’s surface,” says NASA. “But geologic studies of the Eye of Sahara reveal it is actually an uplifted geologic dome, also known as a domed anticline.”
“Over time, differing erosion rates between various rock types in the exposed upper dome led to the formation of circular ridges known as cuestas. Varying color tones in the image reveal different sedimentary and igneous rocks exposed in the structure and landscape.”
“Expansive dune fields sandwich the dome and exposed rock rings. Longitudinal (linear) dunes sprawl across the lower half and top right of the photo. The center-left includes transverse dunes, which develop perpendicular to the wind direction.”
The photograph was captured by an astronaut onboard the International Space Station (ISS).
Image Credit: NASA Earth Observatory
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By Chrissy Sexton, Earth.com Staff Writer
