Oligocene/Early Miocene E/W-Shortening in the Oman Mountains Related to Oblique Arabia-India Convergence

Field survey, literature review, geological map interpretation, GPlates reconstruction and LA-ICP-MS U-Pb dating of synkinematic calcite demonstrate that similar to E/W-shortening in eastern Oman was significant and related to oblique convergence of Arabia and India from 32.5 to 20 Ma. Approximately N/S-striking contractional structures, WNW to NNW-striking sinistral faults and similar to E/W-striking normal faults characterize a similar to 250 km x similar to 50 km wrench corridor in the eastern Oman Mountains (Hajar Wrench Corridor, HWC). Numerous faults/folds indicate that deformation of the HWC is widely distributed but concentrated along WNW to NNW-striking major faults at the SW margin of the Saih Hatat Dome, forming the Hajar Shear Zone, which reactivated basement faults. GPlates reconstructions reveal that N-drifting India rotated 8 degrees counter-clockwise with respect to fixed Arabia from 32.5 to 20 Ma, leading to a minimum of 100 km E/W convergence between both plates. This convergence created the sinistral HWC with a displacement of a few to several tens of kilometers. Independently from the GPlates time constraints, two U-Pb ages of synkinematic calcites, crystallized along faults during HWC movement, yield compatible ages of 30.08 0.47 and 22.31 +/- 2.15 Ma (2 standard error). E/W-shortening also affected the northern Oman Mountains, creating the similar to N/S-striking Hagab Thrust in the Musandam Peninsula and the Jabal Hafit Anticline. Plain Language Summary Northeast Arabia is famous for Late Cretaceous (similar to 95-75 Ma) top-SSW obduction of the Semail Ophiolite. NNE/SSW-shortening caused the main uplift of the Oman Mountains during the Eocene/Oligocene (similar to 40-30 Ma). We report on an important phase of E/W-shortening in the Oman Mountains at similar to 32.5-20 Ma. Our work is based on field survey, literature review, map interpretation, GPlates reconstruction and U-Pb dating of carbonate. We argue that E/W-shortening of 100 km was related to far-field effects of the counter-clockwise rotation of India with respect to Arabia. In response to this shortening, a NW-striking sinistral wrench corridor with widely distributed strain formed (i.e., N/S contractional structures, E/W extensional structures, WNW-striking sinistral Riedel faults, and SW-striking dextral anti-Riedel faults). We name this corridor is the "Hajar Wrench Corridor," encompassing an area of 250 km by 50 km. Concentrated deformation within this corridor at the southwestern margin of the Saih Hatat Dome and beyond formed the Hajar Shear Zone (HSZ). Presumably NW-striking deeply rooted pre-existing faults facilitate shearing along the HSZ. E/W-shortening also affected the northern Oman Mountains and is responsible for deformation at the Hagab Thrust in Musandam and the Jabal Hafit Anticline at the Oman/UAE border.