TECTONIC AND CLIMATIC IMPLICATIONS OF ALLUVIAL-FAN SEQUENCES ALONG THE BATINAH COAST, OMAN

Along the Batinah coast in northern Oman, seven levels of alluvial fan remnants stretching from the Oman Mountains to the Gulf of Oman were considered evidence for Quaternary uplift by previous workers. We suggest that these regionally extensive fan remnants were instead caused by Quaternary climate fluctuations acting on the Oman Mountain headwaters and the major wadi systems. The gradients of these wadis were oversteepened twice: by mid-Tertiary uplift of the mountains and by a major Plio-Pleistocene alluvial aggradation event. Wadi channels are still being cut through this massive deposit. The episodic nature of climatically induced downcutting has produced the fan-terrace levels. The southern Batinah coast is a hinge zone about which the Arabian plate is tilting as it collides with the Eurasian plate. To the north, the Musandam peninsula and the associated fans are subsiding in response to subduction. To the south, uplifted marine shorelines suggest an apparent rigid plate response to the northward subduction.