Geometry and Kinematics of Qom-Zefreh Fault System and its Significance in Transpresssion Tectonics

摘要

Qom-Zefreh fault system, almost 220 km long cuts Urumieh-Dokhtar magmatic belt in central Iran. According to trend and mechanisms, fault can be divided into three segments of northwest, central and southeast. Geometric analysis of structures related to Qom-Zefreh fault system and their kinematics (such as Natanz fault slice), reflects a dextral strike-slip displacement with small reveres component in some parts of Qom-Zefreh fault. The trend of reverse and thrust faults in relation with Qom Zefreh faults well as geometric attribute of developed folds with these faults reveals the influence of strike-slip movement at Qom-Zefreh fault on their formation and development. The movement created a positive flower structure in two areas, pressure symmetric areas of south Kashan and south Ardestan. Compared with these two areas, two areas of north kashan plain in northeastern and southern Zefreh plain?-Gav khoni; swamp in southeast have been affected symmetrically by extension areas of this strike- slip fault system. Verity of lens shaped intrusive bodies including Vash granite are found in local extension areas along some segment of this strike slip fault system. Qom-Zefreh fault as one of basement faults of central Iran is evaluated by general trend of northeast reactivated by convergent tectonic of the Neo-Tethys. Morphological evidence like cuttings and displacement of streams channel and recent alluvial fans along Qom-Zefreh fault provides fact that the mentioned fault has high potential for seismological activity.