Tin Bider crater

Tin Bider is an impact crater that sits in dry, rugged terrain in Algeria. The crater was formed in the last 70 million years, perhaps in the late Cretaceous or early Tertiary Period. Spanning 6 kilometres, the crater sits at the southern end of a range of hills. The elevated position and concentric rings of Tin Bider suggest that its structure is complex.

Massive sandstones attributable to the Lower Cretaceous, known throughout the Sahara, are only exposed in the craters centre, about 500 meters above its usual stratigraphic position.