Structural Analysis of Dowgonbadan Region, Zagros Fold Thrust Belt,An Instance of Frontal and Lateral Ramp

Structures in fold-thrust belts such as Zagros which are developing mainly along the belt strike often terminate at the transverse structures. The Zagros Mountain Front Fault has cut and displace at different parts by transverse structures. At Dowgonbadan area this fault is intersected by the Kharg-Mish transverse structure. The Mish anticline has transported fault propagation geometry and located on hanging wall of the Mountain front fault. The anticline plunges and rotates when it reaches to the Kharg-Mish transverse fault to the west. In the fault footwall, however, the Dil, Pahn, Sarab and Jafarabad anticlines have rounded geometry and low amplitude show characteristics of the Dezful Embayment zone folds.The Dil and Pahn anticlines with bifurcate geometry and outcrop of Asmari Formation develop parallel to the frontal ramp strike and show footwall anticlines that propagated from the frontal ramp at Dashtak formation as delay structures with respect to the hanging wall structures.The Kharg-Mish fault identify as a lateral ramp on the surface by termination of longitudinal structures and at the depth with thickness and facies changes of the Ilam Formation. The structural characteristics of the Dowghonbadan area in the Zagros Fold-Thrust Belt are analyzed as the interaction of the Mountain Front fault and the Kharg-Mish transverse fault as the frontal and lateral ramps, respectively.