The influence of Cenozoic Eurasia-Arabia convergence on the Southeast Arabian Foreland Basin: new geochronological and geochemical constraints from syn-kinematic carbonate mineralization.

The Cenozoic succession of the Jabal Hafeet anticline yields the most complete surface expression of the deformation that affected the Southeast Arabian Foreland Basin (SEAFB). The carbonate rocks of the Eocene Rus Formation comprise the core of the Jabal Hafeet anticline and host a network of fractures and carbonate veins associated with dynamic fracture opening and sealing events. These fracture networks developed during the propagation of compressional stresses from the Makran and Zagros fold-and-thrust belts into their foreland basin system (the SEAFB) and are associated with Arabia-Eurasia convergence. Syn-kinematic calcite veins associated with the Cenozoic folding events in the SEAFB were dated by U-Pb LA-ICP-MS carbonate geochronology and characterized further by Raman fluid-inclusion geochemistry. The U-Pb data show that Cenozoic compression linked to the propagation of the Makran fold-and-thrust belt into the SEAFB took place from c. 20 Ma (early Miocene) to c. 2 Ma (mid Pleistocene). Raman fluid-inclusion data reveal the presence of complex hydrocarbons within the parent carbonate-bearing fluids, reflecting a fluid transport pathway between the upper Cenozoic rocks and deeper hydrocarbon-bearing Mesozoic sequences. Combined isotopic and geochemical datasets show that the deformational history of the SEAFB is likely related to the reactivation of inherited deep-seated structures in the upper Cenozoic stratigraphic sequence due to the far-field stress propagation from the Makran belt into the Arabian peninsula, rather than the propagation of a thin-skinned deformation architecture.