Structural analysis of ParPar Mountains in Zagros collisional orogeny, NE of Shahrekord

Parpar Mountains is located in northeastern part of Shahrkord City, in Zagros collisional orogeny, and in the transition zone from the Sanandaj Sirjan (SSZ) to High Zagros zones. The mountains consists of Jurassic and Lower Cretaceous rocks. Former structural analysis of the Zagros collisional zone resulted in two proposition in which the Zagros oblique orogeny occurred as a right lateral transpression in Early Tertiary or partitioning of displacement between the strike-slip and reverse faults in Late Tertiary. Field studies show that faults are of oblique mechanisms with generally two main trends. The NW-trending faults have oblique Dextral Reverse kinematics whereas the NE-trending strike-slip faults have reverse or normal dip-slip components. Along the NW-trending faults, which also control the region morphology, positive flower structures are developed. These faults cause the mountains to poped-up against the low land around it.  The rhomboids shape of the mountains as a result of “R” and “P” Riedel shear faults interplay as well as development of oblique inclined folds is taken into account for transpression deformation of structures in the study area as a part of Zagros oblique collisional zone. Since the faults displaced the Late Tertiary rocks, this transpression deformation is proposed to occurr at least before Late Tertiary.