中国阿尔泰造山带南缘额尔齐斯断裂带的构造变形及意义  

Structure deformation and tectonic significance of Erqis fault zone in the southern margin of Chinese Altay

作　　者：刘飞[1,2] 王镇远[1,2] 林伟[1] 陈科[1] 姜琳[1,2] 王清晨[1] 

机构地区：[1]中国科学院地质与地球物理研究所,岩石圈演化国家重点实验室,北京100029 [2]中国科学院大学,北京100049

出　　处：《岩石学报》2013年第5期1811-1824,共14页Acta Petrologica Sinica

基　　金：国家科技重大专项(2011ZX05008-001);国家自然科学基金项目(41225009)联合资助

摘　　要：额尔齐斯断裂是中亚造山带中的一条重要深大断裂,对于额尔齐斯断裂运动性质一直有着走滑断层、逆冲断层和压扭性断层等不同看法。本文在中国阿尔泰造山带南缘开展了详细的构造地质学工作,研究结果表明,额尔齐斯断裂及其次级断裂组成额尔齐斯断裂带。额尔齐斯断裂带在中国境内是一条宽约20～40km,长约400km,经受不同程度构造作用的强应变带,剪切作用影响范围遍布整个中国阿尔泰造山带南缘。额尔齐斯断裂带经历了左行走滑和右行走滑两个阶段。结合前人有关韧性剪切带成因型金矿、同构造岩体侵位与变形关系及对变质岩石40Ar/39Ar年代学研究,本文认为额尔齐斯断裂带的左行走滑构造形成于早二叠世(283～275Ma)。早二叠世之后,额尔齐斯断裂带叠加了右行走滑事件,其活动时限可能为晚二叠世(260～245Ma),其规模远远小于前期的左行走滑构造。额尔齐斯断裂带走滑活动性质的确定,为二叠纪北疆及整个中亚造山带造山后调整过程中不同的构造方式提供了佐证。As one of the most significant regional faults in the Central Asian Orogenic Belt, the Erqis fault was hotly debated on its kinematics. Three representative models have been proposed： strike-slip fault, thrust fault or transpressional fault. Our work in southern margin of the Chinese Altay indicates that the Erqis fault and its subordinate faults compose the Erqis fault zone, which is a ductile high strain zone with 20 -40kin in width and 400km in length, and experienced variable deformation. All the southern margin of the Chinese Ahay was influenced by ductile shearing. The Erqis fault zone experienced two tectonic events： sinistral strike-slip and dextral strike-slip shearing. Combining our work with the existing studies of the ductile-shear-zone-type gold deposits, syntectonic deformed plutons and ^（40）Ar/^（39）Ar ages in metamorphic rocks, it is inferred that the sinistral strike-slip event occurred in the Early Permian （283 - 275Ma）. Thereafter, probably in the Late Permian （260 -245Ma）, the Erqis fault zone was partially modified by a dextral strike-slip event which was much weaker than the former. Furthermore, based on the establishment of the kinematic model of the Erqis fault zone, important lines of evidence have been brought forward to discussing the post-orogenic adjustment during the

关 键 词：韧性剪切带 左行走滑 右行走滑 额尔齐斯断裂带 中国阿尔泰造山带南缘 

分 类 号：P542.3[天文地球—构造地质学]