Structural Analysis of the Zagros Collision Zone, West Aligodarz

The style of deformation changes from the hinterland (Sanandaj-Sirjan zone) to the foreland (Zagros) through the Zagros Orogen containing thick-skinned and thin-skinned deformation respectively. NW-SE trending thrust faults dipping to northeast have carried the older rock sequences to the surface. The Zagros collision zone could be divided into two distinct parts based on deformation mode that is separated by the Main Zagros Thrust. The southwestern part contains imbricate thrust sheets instead, to the northeastern part large amount of shortening is documented by basement deformation with duplex structures. Abundant crystalline deep origin thrust sheets have transported (2 up to 20 km) the metamorphic rock units upon the Zagros suture zone by gravity or tectonic forces.Despite the collision thrust faults, both NW oriented (Main Recent Fault) and NE oriented (named here Azna Fault) basement wrench faults have also activated and caused different style and amount of deformation in the collision zone.