قاع البحر القديم
Wadi Dahek is a valley cut by two faults and widened by erosion. It offers a spectacular look into the substrata of the Eastern Desert that formed in a marine environment between 65 and 25 million years ago (known as Wadi Shallala formation). Visible in the exposed layers is marl (clay and lime), chalk, limestone, gypsum, chert, flint, concretions, hoodoos, buttes, pinnacles, and marine fossils (especially durable shark teeth).
Wadi Dahek, with its deep end in Jordan and its shallow end in Saudi Arabia, is south of Azraq, about 8 km northeast of Umari, around the GPS coordinates: 31.5717°, 37.1217°.