The role of faults in deformation pattern of the Ahangaran Pb-Ag (Zn) deposits, SW Hamedan

The Ahangaran Pb-Ag (Zn) deposit is located in the Sanandaj-Sirjan zone and in the NW part of the Malayer-Isfahan Metallogenic belt. Mineralization and mineral horizon in this deposit is formed in dolomitic sandstone and dolomitic limestone of Kc3 unit. The aim of this study is structural analysis and investigation of the fault systems affecting the mineralization in the Ahangaran Pb-Zn deposit. For this purpose, field observations, study of satellite images, orthophoto images and digital elevation models have been used. The results of this study indicate that the nappes moving from the NE to the SW caused the orbitulin limestone of the Kl unit to be thrusted over the younger lower Cretaceous units. The Koh-Darrehghar fault with N33°E trend and left-lateral separation has caused a displacement of about 2600 meters in the eastern part of the study area. Fractures in the study area have three main trends including N20°E to N35°E, N02°E to N20°W and N30°W to N60°W. The Darreh-Somagh, Tunnel and East-Road fault zones are the main effective structures that have divided the study area into four structural zones. These faults with normal separation have caused the displacement of mineralized horizons. The Tunnel and East-Road faults with normal separation and dip towards the east have caused downward movement of the Kc3 unit in the hanging wall. Also, Pb-Ag (Zn) mineralization is widely formed in the fractures of the second and third zones.