Late Cenozoic Faulting at Ziar Area in Central Alborz

Abstract

Field investigation and structural mapping of faults cut Mezozoic to Late Cenozoic (PlioceneQuaternary) rocks in Ziar area of Central Alborz have led to identification of the NW- and NE- trendingfault sets. Slickenlines, fault steps and riedel shear fractures are mainly applied as kinematic indicatorsfor analysis of the faults mechanisms. The NW-trending reverse faults with left-lateral strike-slipkinematics and positive flower structure geometry (such as Golezard Fault) is the first set. This set cutthrough all rock formations up to Plio-Quaternary are proposed to develop during the northeasternoblique transpression deformation governs the Alborz during the final collision of the Arabian- Eurasianplates 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 theregion. This fault set development have attributed to the northwestern movement of the South Caspianblock in Quaternary, which led to an extension in Central Alborz. These young faults mapped for thefirst time in this work constrain the Late Cenozoic (Quaternary) faulting of Central Alborz zone, referredas a result of the range major faults reactivation, previously.