Style and timing of salt movement in the Persian Gulf basin, offshore Iran: Insights from halokinetic sequences adjacent to the Tonb-e-Bozorg salt diapir

Abstract

The variations in the rate of salt rise is reflected in the sedimentary sequences adjacent to salt diapirs and provides insights into the style of salt movement-sedimentation interaction and the timing of halokinetic phases. Episodic movement of salt diapir is defined by wedge- and tabular-shaped salt-related sedimentary strata (halokinetic sequences) adjacent to the diapir. Detailed mapping of depositional strata on 2D seismic sections adjacent to salt diapirs on the Tonb-e-Bozorg Island (Persian Gulf, SW Iran) reveals the presence of a series of sedimentary sequences related to the halokinetic activity of two salt source layers, the Hormuz and Fars salts, respectively. The Hormuz salt deposited in the uppermost Proterozoic, mobilized in the Lower Paleozoic and then continued to move periodically to present and to create the deep salt structures in the Tonb-e-Bozorg region. The Fars salt deposited in the Lower Miocene and then started rising, and created the central salt structure, the Tonb-e-Bozorg Island, and several peripheral ring-like salt structures around the island. Our results reveal that both the salt layers within the Tonb-e-Bozorg region grew by downbuilding and continued to move periodically by passive and active diapirism to the present. Salt movement-sedimentation interaction during salt diapirism influences petroleum play and therefore is of interest in petroleum geoscience.