Kinematic Analysis of Folding in Anticline Structures in the Interior Fars Region

Fars region in southwest Iran lies at the Zagros foreland and is bounded to the north and east by the Zagros thrust, to the west by the Kazerun fault, and to the south by the Hormoz Strait and the Persian Gulf. Thrust faults and associated folds are the main structures in the Fars region. The structures are trending NW to SE, the same trends as in the Zagros fold- thrust belt. The structural analysis of four anticlines in the interior Fars region based on the interpretation of seismic reflection lines and construction of structural sections on the basis of well data and field measurements indicates that fault propagation folds and fault detachment folds can be distinguished taking into consideration the geometry of the folds and the fault-fold relations. Based on measured parameters, the Ghareh Bulagh anticline is consistent with a fault propagation structure, while the Derz and Shirkhan anticlines with fault detachment structures. According to seismic reflection profiles and structural cross sections, the Chahkileh antiform is converted to a syncline at depth. The extent of shortening, based on the balanced structural cross sections, has been calculated to be around 14 percent.