ABSTRACT
The surface of Southeast Arabia west and south of the Oman Mountains is covered by a combination of fluvial (wadi) aeolian, and coastal and inland sabkha sedimentary sequences. Following mid-Tertiary uplift of the Oman Mountains, much of the area probably became exposed to sub-aerial sedimentation during the Pliocene, following a global fall in sea level. Since then, the climate has alternated between being relatively humid and arid or hyper-arid. Aridity coincided with repeated high-latitude glacial events, which caused the sea level to fall by 120–130 m; at these times, the Arabian Gulf was dry, and the site of sand dunes migrating to the S or SE towards the Emirates and the Rub’ al Khali. Interglacial periods brought increased humidity, a partially stabilized system of dunes and a Gulf that was flooded by sea water to about the same level as today. The resulting end to the supply of dune sand to the Emirates was followed by deflation down to a regionally rising water table and the creation of both inland and coastal sabkhas. At times of glacially lowered sea level, the continental shelves were exposed to deflation of their carbonate microfauna; in areas of onshore winds such as the Emirates and along the Arabian Sea and Gulf of Oman coasts, carbonate-rich dune sands were deposited during earlier glaciations, and were cemented into rock following later periods of higher humidity. The Wahiba Sands of SE Oman is the latest product of the onshore-blowing SW Monsoon, and are still unconsolidated.
