Located at Mianyang-Lueyang plate suture zone, Yangshan gold deposit experienced the transforma-tion of the complex structural system that the main structural features were the thrust-nappe structures. According to route geological survey a
Located at Mianyang-Lueyang plate suture zone, Yangshan gold deposit experienced the transforma-tion of the complex structural system that the main structural features were the thrust-nappe structures. According to route geological survey and drill core record, we divided the structural period of Yanshan gold deposit based on the research of small structure and identified four structural periods. Faults were the main structure and folds were subordinate structure in Yangshan gold deposit.The first period of structural deformation was ductile defor-mation and thrusted form north to south.There were obvious and complete transposition structures , and a lot of ductile deformed structures, such as shear folds, rootless folds, S-C fabrics, pressure shadows,rotating mortar sys-tems, domino structures, and boudinage. The first deformed period formed in Late Triassic- Lower Jurassic , which tectonites were mylonites, ultramylonites and tectonic schists as well as massive granite magmatism.The structural deformation of the second period was extensional structure, trending north to south direction,which changed and reuseed the first period foliation structures. The structures of two period were small-angle cross-cut-ting or parallel output. The structures of the second period showed ductile deformation that formed shear folds, fo-tating mortar systems,which tectonites was mylonites. Bedding tensional quartz veins developed as well as mas-sive granite magmatism. The second period structures formed in Late Jurassic-early Lower Cretaceous. The struc-tures of the third period were brittle-ductile deformation showed thrust-nappe structure inverse rushed form south to north. The structures mainly showed the transformation of the early structures, and specific performed the re-verse of the foliation attitude in the southern area of Yanshan gold deposit, (i. e. foliation tendency changed from north to south), formed kink structures. The third deformed period formed in the late period of Lower Cretaceous, which tectonites were mylonites and protomylonites. The structures of the fourth period were surface-level brittle deformation,which was extensional structure trending south to north direction. Structural breccias cataclasites, bedding tensional quartz veins and calcite veins along the period faults formed . The structures of the fourth peri-od formed in the Paleogenecentry.