oa Salt diapirism in the fold-thrust belt and foreland basin in the eastern Fars Province, Iran

The Hormuz Series crop out as salt plugs in the Zagros Fold-Thrust Belt or as islands forming circular domeshaped structures in the Persian Gulf. The 7 to 12–kmthick sedimentary cover is decoupled from its basement by the Hormuz Salt layer and deformed by large-scale folding and thrusting that started in the Miocene Epoch. Recent emergent diapirs occur above the crests of preexisting domes, at the crest, nose or plunging axes of the folds. We also observed Hormuz residual along some thrust or wrench faults in the inner part of the fold-belt. A study of salt diapirs in the fold-thrust belt and foreland basin of eastern Zagros was based on seismic and well data analysis, field observations and analogue modeling. Several regional cross-sections were constructed from the Persian Gulf to the Zagros Suture Zone. They allowed us to investigate: (1) the kinematic scenarios for the main structural elements; (2) the role of deep-seated fault on deformation; (3) the role of pre-existing dome and salt intrusions during folding; and (4) evaluate the thickness of the Palaeozoic sedimentary pile. Finally, they present a reference for the pre-folding attitude and activity of salt domes in the foreland basin compared with the fold-and-thrust belt area. Salt plugs in the eastern Fars Province initiated as early as the Palaeozoic time, and were reactivated by subsequent tectonic events. They formed either: (1) emergent diapirs forming islands, especially in the Paleogene to Neogene Sea at the front of the fold-thrust belt, or (2) buried domes. Pre-existing salt diapirs strongly influenced the development of the compressive structures formed during the Neogene Zagros folding, as well as the style of deformation and the localization of the folds.