Saudi Arabia is divided into two main regions: the Arabian Shield in the west and the Arabian Shelf towards the east. The Arabian Shield occupies one-third of Saudi Arabia, roughly 610,000 km2 of the entire Arabian Peninsula. It is mainly made up of metamorphosed sedimentary and volcanic rocks which relate to the Precambrian period, and others are covered by Quaternary sediments. The land slopes gently towards the northeast and east, and, over time, the products of erosion of the Arabian Shield have been carried by wadis toward the Arabian Shelf. The Arabian Shelf is located to the east of the Arabian Shield, where it occupies roughly two-thirds of the Arabian Peninsula. Its sequence is made up of continental and shallow marine sedimentary rocks. The Arabian Shelf sequence dips gently away from the Shield towards the Arabian Gulf with an average 1°, consists of parallel cuestas separated by depressions commonly occupied by aeolian deposits (e.g. Nafud Al Thuwayrat, Nafud As Sirr and Nafud Al Tarafiyah).

Autorentext

Dr. Ahmed Abdullah AldughairAssociate Professor of GeomorphologyQuaternary science and Remote Sensing Geography Department - Qassim University