Tin Bider is an ancient and eroded meteor crater on the Tin Rhert Plateau in the Algerian Sahara. Tin Bider is nearly 6 kilometers (3.7 miles) in diameter and was caused by a meteorite impact in this region of northern Africa roughly 70 million years ago. The other streaks near the crater are unrelated to the impact event. These rock folds are geologic features older than the crater. August 31, 2009.