Seismic stratigraphic insights into sediment-loading concentric growth of the Abu Musa salt diapiric system (SE Persian Gulf)

The world-class Oligocene–lower Miocene Fars Salt diapirs and fully-imaged minibasins in seismic data around Abu Musa Island, Persian Gulf, provide a unique opportunity to study temporal-and-spatial growth of diapiric systems independent of significant regional compression, extension, or shearing, beyond the Zagros and UAE–Oman's fold belts deformation fronts. The system is globally unique for its concentric array of elongated curved salt walls/anticlines encircling a central salt stock, shaping a ring-like map-view geometry. We subdivided the salt-expulsion minibasins into five unconformity-bounded tectonostratigraphic successions with distinctive thickness patterns and shifting depocenters, enabling step-by-step restorations that reveal the basin’s halokinetic history: The Abu Musa salt system developed a concentric geometry through ca. 10–12 Myr of radial growth, driven by sediment-loading–induced halokinesis. After deposition of several hundred meters of pre-kinematic strata above approximately 1 km of the Fars Salt, diapirism initiated in the middle Miocene with continuous passive growth of the central salt stock. Salt-expulsion-related subsidence beneath the rim-synclinal minibasin produced outer flank anticlines and monoclines with concentric axial trends. Downflexure at anticlinal hinges created steep, inward-dipping normal fault zones providing space for rising and piercing salt rollers/horns, which ultimately evolved into salt walls by the late Miocene (reactive–passive diapirism). Diapirism ended diachronously with progressive salt primary welding by the middle Pliocene. Overall, this sediment-loading-driven mechanism, and the transition from faulted salt anticlines to piercing salt walls, formed independently of underlying basement faults or regional stress and may also be more widespread in other salt basins worldwide than previously recognized. • Seismic sequence stratigraphy and sequential restoration constrain the Abu Musa halokinetic history. • Sediment loading drives salt diapirism beyond the Zagros and UAE–Oman deformation fronts. • Normal faulting of salt anticlines triggers the transition to piercing salt walls. • 11 Myr of concentric growth of the Fars Salt system shapes a globally unique geometry.