Analog Models of Faults Associated with Salt Doming and Wrenching: Application to offshore United Arab Emirates

Abstract

Regional stress has a significant impact on fault development during the formation of salt dome structures. To examine such effects of wrenching, we conducted a series of analog experiments of updoming using dry, granular materials and observed the deformation on the top free surface. The experiments included three deformation styles: (1) updoming followed by wrenching, (2) simultaneous updoming and wrenching, and (3) wrenching followed by updoming. In the first series of the experiments, the faults produced by simple updoming were overprinted by two strike-slip fault systems that were generated by the subsequent wrenching. The second series of experiments with the configuration of simultaneous updoming and wrenching generated normal faults in a direction perpendicular to relative extension by the wrench. In the third series of experiments, the Riedel and anti-Riedel shear faults formed by wrenching were deformed by the subsequent updoming and were overprinted by the faults related to the updoming. These experimental results are applied to the fault systems observed above dome structures in the United Arab Emirates region, where extensive faults in the northwest–southeast direction have developed. By analogy, these faults were probably formed during an updoming and simultaneous wrenching. The direction of simple shear inferred from a comparison of real faults and experimental results suggests that dextral wrenching caused by the Oman stress regime during the Late Cretaceous affected the region at the time of the updoming.