Controls on the Geometry and Evolution of Salt Tectonic Structures Along Salt‐Bearing Passive Margins

Abstract Passive rifted margins comprise some of the largest and thickest (up to ∼4 km) salt basins in the world and exhibit some of the most complex salt tectonics. In the majority of these, the salt is deposited during the final stages of rifting, prior to continental breakup and oceanic spreading, with most of salt deformation occurring during the post‐rift. Post‐rift salt tectonics is controlled primarily by the differential load of supra‐salt sediments and the slope of the salt basin producing kinematically‐linked domains of deformation. Despite their similar geodynamic context and timing of salt deposition, salt tectonic evolution and structural styles vary significantly for salt‐bearing rifted margins. Our study aims to contribute to understanding what controls different types of salt structures developed along salt‐bearing rifted margins. We use 2D thermo‐mechanically coupled numerical forward models of rifted passive margin formation and salt tectonics to simulate late‐syn‐rift salt deposition and post‐rift salt deformation for different margin types. We focus on analyzing the geometry and dynamic evolution of individual salt structures and their controls along different margin domains for narrow, wide, and ultra‐wide rifted margins. Model results show that salt thickness, base‐salt relief and variations of sediment load are the overarching controls for the relative contribution of Poiseuille and Couette flow. This governs the effects of extension, shortening, vertical subsidence and diapir rise, which control the different types of salt diapirs, minibasins, faults, and rollover systems and their distribution along the margin.