木里地区小金河断裂构造变形及演化

发布时间：2018-12-15 06:17

【摘要】：小金河断裂是龙门山-锦屏山-玉龙雪山中新生代推覆构造带的西南一段,它是松潘甘孜造山带与扬子地台的重要分界。小金河断裂的构造演化、变形特征反映了松潘甘孜造山带的双向造山极性,而已有的对于小金河断裂构造的研究多为发震机制和第四纪以来的活动性的讨论,用构造地质学研究小构造样式及组合却被忽略。本文通过对数条横穿小金河断裂的线路进行野外地质观测,主要运用小构造解析方法,对小金河断裂及其构造带中的小构造进行了几何学及运动学的研究,初步得到以下成果:(1)木里地区小金河断裂主要分为弧形段和棉垭段两段。(1)弧形段北分支断裂可分为博瓦乡断层、红科村断层、黑来沟断层。(2)小金河断裂弧形段主断层大体沿E-W方向展布,向南凸出为弧形,经过芽祖乡和核桃湾。(3)小金河断裂棉垭段主要分为两支,分支1呈NE-SW向展布,经过棉布村、长柏乡;分支2呈NE-SW向展布,经过桃子乡。(2)弧形段主要表现为劈理带、透镜体带、正断或逆冲的小断层,局部发生右旋运动;棉垭段主要表现为劈理带、碎粒带、碎斑带,局部发生左旋运动。(2)将小金河断裂的构造演化划分为六期,分别为:(1)第一期为印支期末的逆冲活动,最大主压应力方向为E-W;(2)第二期为燕山早期的逆冲活动,最大主压应力方向为NW-SE;(3)第三期为燕山期的正断活动,为E-W向拉张应力;(4)第四期为燕山期-喜马拉雅期的逆冲活动,最大主应力方向为NE-SW向;(5)第五期为早更新世的正断活动,为E-W方向拉张。(6)第六期为中更新世以来NW-SE向的逆左旋活动。
[Abstract]:The small Jin He fault is the southwest section of the Meso-Cenozoic nappe tectonic belt of Longmen Mountain, Jinping Mountain and Yulong Snow Mountain, which is an important boundary between Songpan Ganzi orogenic belt and Yangtze platform. The tectonic evolution and deformation characteristics of the small Jin He fault reflect the bidirectional orogenic polarity of the Songpan Ganzi orogenic belt, while the previous researches on the minor Jin He fault structure are mostly the seismogenic mechanism and the discussion of the activity since the Quaternary. The use of tectonic geology to study small structural styles and assemblages has been neglected. In this paper, through the field geological observation of several lines crossing small Jin He fault, the geometry and kinematics of the small Jin He fault and the small structure in the tectonic belt are studied by using the method of small structure analysis. The results are as follows: (1) the small Jin He fault in Muli area is mainly divided into two sections, the arc segment and the Miaoya section. (1) the northern branch fault of the arc section can be divided into Bowaxiang fault, Hongkecun fault, Hailaigou fault. (2) the main fault of the arc section of small Jin He fault distributes roughly along the direction of E-W and protrudes southward, and passes through Yazu Township and walnut bay. (3) the Mianyia section of small Jin He fault is mainly divided into two branches. Branch 1 showed NE-SW distribution, passed through cotton village, Changbai Township; Branch 2 is distributed in NE-SW direction, passing through Taozi Township. (2) the arc is mainly composed of cleavage zone, lenticular zone, small fault with normal fault or thrust, and local dextral motion. The main features of the Miaoya formation are cleavage zone, broken grain zone, debris zone and local left-lateral movement. (2) the tectonic evolution of the small Jin He fault is divided into six stages: (1) the first stage is the late Indosinian thrusting activity, and (2) the tectonic evolution of the small Jin He fault is divided into six stages. The maximum principal compressive stress direction is E-W; (2) the second stage is the early Yanshanian thrust, the maximum principal compressive stress direction is NW-SE; (3) the third stage is the Yanshanian normal fault activity, and the E-W tensile stress; (4) the fourth stage is the Yanshanian to Himalayan thrusts, and the direction of the maximum principal stress is NE-SW; (5) the fifth stage is an early Pleistocene faulting activity, which is an E-W extension. (6) the sixth phase is an inverse left-handed activity of NW-SE direction since the Middle Pleistocene.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P542

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