Late Cenozoic Faulting at Ziar Area in Central Alborz

Field investigation and structural mapping of faults cut Mezozoic to Late Cenozoic (Pliocene- Quaternary) rocks in Ziar area of Central Alborz have led to identification of the NW- and NE- trending fault sets. Slickenlines, fault steps and riedel shear fractures are mainly applied as kinematic indicators for analysis of the faults mechanisms. The NW-trending reverse faults with left-lateral strike-slip kinematics and positive flower structure geometry (such as Golezard Fault) is the first set. This set cut through all rock formations up to Plio-Quaternary are proposed to develop during the northeastern oblique transpression deformation governs the Alborz during the final collision of the Arabian- Eurasian plates in Late Cenozoic (Pliocene). The NE-trending strike-slip faults with normal kinematics that crosscut the Damavand Quaternary volcanic rocks as well as the first faults set are the youngest faults in the region. This fault set development have attributed to the northwestern movement of the South Caspian block in Quaternary, which led to an extension in Central Alborz. These young faults mapped for the first time in this work constrain the Late Cenozoic (Quaternary) faulting of Central Alborz zone, referred as a result of the range major faults reactivation, previously.