Folding and Faulting in Irankuh Mine Area, Isfahan

Irankuh is located 20 km south of Isfahan. Late Jurassic black shale, silt and sandstones are the oldest rocks in the area that exposed in the northern flank of the Irankuh Mountain. Lower Cretaceous dolomitic limestone with some shale and marl starting with a basal conglomerate, overlay the Jurassic sediments in the area. Folds are trending NW-SE. In the northern flank of Irankuh a Kilometer scale Syncline with vertical axial plane and axis plunges of 35° to the west and an anticline with 32° plunges to the west and its exposure extended toward the southern flank of mountain. According to competency contrast of the rock units, abundant minor folds consistent with the geometry of the major structures are produced in couple of synclines and anticlines. Goushfil-Tapeh Sorkh reverse fault (75° dipping to the NE) thrust the Jurassic sediments over the Cretaceous rocks in Goushfil and Tappeh Sorkh1 Mines. Field observations indicate that it was originally a normal fault dipping to the SW and has been changed during the course of folding process to an inverted high angle reverse fault dipping to the NE close to the surface. NW-SE trending reverse faults are controlling the mineralization in the Irankuh area i.e. Goushfil-Tapeh Sorkh reverse fault.