Aorounga
ADDPMP766The exposed remnant of the Aorounga crater is 12.6km (7.8 mi) in diameter; its age is estimated to be less than 345m years (Carboniferous or younger).
Aorounga is composed of an outer and an inner ring, respectively 11 and 7km (6.8 and 4.3 mi) in diameter, that rise about 100m (328 ft) above the mean level of the surrounding plain. Both aforementioned rings are separated by a relatively flat depression of uniform width. A possible central hill, which could be an uplift structure of 1.5km (0.9 miles) is almost centrally located in the depression.
The central highland, or peak, of the crater is surrounded by a small sand-filled trough; this, in turn, is surrounded by a larger circular trough. Linear rock ridges alternating with light orange sand deposits cross the image from upper left to lower right; these are called yardangs by geomorphologists. Yardangs form by wind erosion of exposed rock layers in a unidirectional wind field.
The crater is accompanied by two nearby circular features revealed by Space Shuttle SIR-C radar. These may be related impact craters, and if this hypothesis is correct, Aorounga may be part of a crater chain. That is why the exposed Aorounga crater is sometimes referred to as Aorounga South.















































































































































































































































































































































































































































































































































































































































































































































































































































