Plain Language Summary
Eastern Arabia was thrusted by the well-known Semail Ophiolite and
related deep-sea sedimentary rocks during the Late Cretaceous.
Convergence was directed towards the SSW. Ongoing ~N/S
shortening between Arabia and Eurasia resulted in respective deformation
within the Oman Mountains. However, field evidence indicates that
~E/W-shortening affected the Oman Mountains, too.
Detailed and comprehensive field survey, literature review, satellite
image interpretation, map interpretation, GPlates reconstruction and
absolute U-Pb dating of carbonates documents that E/W-shortening was
significant in the Oman Mountains. E/W-shortening of 100-135 km was
related to the counter-clockwise rotation of India with respect to
Arabia at 32.5 to 20 Ma. In response to this shortening, a NW-striking
sinistral shear zone with wrench-fault assemblage formed in the eastern
Oman Mountains (i.e., N/S-compressive structures, E/W-extensional
structures, WNW-striking sinistral Riedel faults, and SW-striking
dextral anti-Riedel faults). This shear zone is the Hajar Shear Zone,
which spans an area of 250 km by 50 km. Presumably NW-striking deeply
rooted pre-existing faults facilitate shearing along the Hajar Shear
Zone. 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.