New Data on the Geological Build-Up of the Central Oman Mountains
In 2006 and 2007 geologists from MOL-Hawasina LLC conducted field trips to examine the structures in the central Oman Mountains. Bedding, cleavage, fold and fault data were recorded during the field work. We found numerous differences from the otherwise excellent published BRGM map. According to this fieldwork, we redrew the published geological map, and compiled new geological cross-sections across the Hawasina Window. Three main structural units build-up these mountains: (1) the uppermost Semail Ophiolite, (2) the oceanic Hawasina Nappes, and (3) the lowermost tectonic unit, the Arabian Platform. Within the Hawasina Nappes, the slope-facies Sumeini Unit, the abyssal Hamrat Duru Unit and fragments of the oceanic island Umar Unit can be differentiated. In the Hawasina Window, the oceanic nappes come to the surface from beneath the ophiolites. Five main differences are noted between our interpretation and the formal geological map. (1) The original stack of Hawasina Nappes underwent out-of-sequence thrusting, and at least three complex nappes were recognised. (2) The tectonic boundaries of the Hawasina Window are steep, normal- or strike-slip faults, cross-cutting the original nappe boundaries. (3) Two main strike-slip corridors in the southern and northern edges of the Hawasina structure were mapped. (4) Three main antiforms were recognised inside the Hawasina Window. (5) We observed several occurrences of small gypsum diapirs in the Wadi Dil-Wadi Hawasina area; these evaporite bodies rise from beneath the Hawasina Nappes. We suggest that they belong to the Palaeozoic of the underlying Arabian Platform. Both MOL Hungarian Oil & Gas Plc and Hawasina LLC Oman Branch wish to thank the Exploration Directorate of Ministry of Oil & Gas of the Sultanate of Oman for the continuous support to the work.
AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain