Structure of Richat

The Structure of Richat or dome of Richat (called the eye of the Africa) close to Ouadane in Mauritania into full Désert with the the Sahara is a " extremely rare scientific enigma " 50 km in diameter, only visible since the space. Discovered in 1965 by a American mission Gémini . It would be according to last scientific interpretations Géologique S, the results of a giant volcanic eruption " particular " , old woman of 100 million years (Cretaceous), completely ploughed up following long a erosion.

Discovered

This structure was for the first time described in the charts to the 1/200 0000 of the French National Geographical Institute in 1963. It thereafter drew the attention of the first space missions because of its characteristic form in Oculus in a rather monotonous desert landscape.

Described by some like a gigantic Ammonite in the desert, the structure, which has a diameter of almost 50 kilometers and to uneven to 300 to 400 m, became a benchmark for the crews of the space shuttles.

Scientific interpretation

Initially interpreted like a structure of impact of Meteorite because of its strong circularity, the Géologue S think then of a symmetrical rising of type circular Anticlinal.

They currently think since the Années 2000 which they are the results of a rare form of volcanic eruption giant old woman of 100 million years (Crétacé), who created a volcanic knob which ended up crumbling completely following long and slow a erosion. (Video Podcast of the emission “Discovered” of Radio-Canada in 2006)

Quartzite S of the Paléozoïque form the parts of the structure which resisted erosion.

With the Cretaceous (- 145 to -65 million years): the ic activity Volcan is important. The Ground is inhabited primarily by the Dinosaure S and the Reptile S. the Mammifère S are small and have only little importance in the animal kingdom.

See too

geological Time scale

External bonds

of the emission “Discovered” of Radio-Canada in 2006
Seen original of NASA Earth Observatory
Astronomy Picture off the Day

Random links: