磨西断裂变形与运动学特征研究

磨西断裂位于鲜水河活动断裂带的东南侧，北段为松潘-甘孜地槽褶皱系与扬子陆块的分界，南段则伸入扬子地台内部，成为扬子地台西缘拗褶带与康滇地轴的分界，是扬子西缘不同构造单元的控制性断裂构造。通过宏观分析地层分布，磨西断裂北段磨西磨子沟（新近崩塌出露），中段湾东剖面和南段新民腊树岗剖面的构造变形、几何学与运动学特征，收集整理擦痕资料，再结合糜棱岩微观石英C轴组构特征，认为磨西断裂曾经历5次强烈活动：早期为正断性质，西低东高，控制两侧沉积分异（晋宁期）；中期为韧性逆冲（印支期），形成糜棱岩；晚期新近纪中新世又一次韧性逆冲，之后又经历了脆性左旋逆冲、脆性左旋逆冲平移两次强烈活动（喜马拉雅期）。

Structural deformation and kinematics of the Moxi fault in western Sichuan

Located on the southeastern flank of the Xianshuihe fault, the Moxi fault constitutes the boundary between the Songpan-Garze geosynclinal fold system and Yangtze landmass in the north, and between the western Yangtze platform fold zone and Xikang-Yunnan axis in the south. In the light of the structural deformation, geometry and kinematics, striation and microscopic quartz C-axis petrofabrics of the mylonite in the Mozigou, Wandong and Lashugang sections, the Moxi fault has spanned five phases of intense faulting, including the normal faulting in the early stage （Jinningian） , ductile thrusting resulting in the formation of mylonite in the middle stage （Indosinian） , ductile thrusting once again in the later stage during the Miocene, brittle sinistral thrusting and brittle sinistral thrusting-translation （Himalayan）.