Effects of interactions between deformation, erosion and syntectonic sedimentation on the geometry and arrangement of structures in the central part of the Zagros fold-thrust belt, SW Iran

In the Neogene foreland basin of Zagros, Dezful Embayment as a foredeep depozone has accommodated large volumes of deposits of Aghajari and Bakhtiary formations. In this paper, surface and subsurface data and experimental modeling approach have been used to study the effect of these sediments on the geometry and arrangement of structures in the central part of Zagros fold-thrust belt. The experimental modeling suggests that simultaneous performance of erosion and syntectonics sedimentation prevents deformation propagation to the foreland, and rather concentrates it on the structures already formed toward the hinterland. In this regard, anticlines formed toward the hinterland respond to this process by uplift, faulting and limb rotations. With shortening progress, a large-scale anticline is developed toward the foreland after syntectonic sedimentation. Based on experimental modeling, the clastic deposits of Aghajari and Bakhtiary formations in the Dezful Embayment have led to the concentration of deformation expressed as steep to overturned anticlinal limbs and thrust fault developments in the southern parts of the Izeh and Lurestan zones. Also, large volumes of these sediments in the middle part of the Dezful Embayment has prevented formation of large anticlines in this part and caused formation of anticlines in the north and south parts of the Dezful Embayment.