桂林-永福断裂北段断层岩显微构造研究

Microstructure of fault rock at north part of Guilin-Yongfu fracture

桂林—永福断裂北段是桂北大断裂带的典型构造区,具有代表性。文章对该断层岩从微观的角度来研究,在塑性变形显微构造和微观运动学特征中可看出,矿物普遍发生细粒化,并发生动态重结晶。各种运动学标志如微观的S-C面理、旋转残斑系、云母鱼、不对称褶皱和微型小断层等都十分清楚且互相吻合。研究表明,韧性剪切带的运动学特征指示上盘向西下滑,为一正滑型的韧性剪切带。这一结果和宏观研究一致,也为该断裂的整体研究提供了有力的证据。

North part of Gulilin-Yongfu fault Zone is not only a representative typical structural area of North Guilin major fault. The fault rock is studied from view of microteetonics in the paper. Fine granulation and dynamic recrystallization took place widely in the minerals, viewed from plastic deformation-microscopic structure and microcosmic kinematics characteristics. All kinds of movement marks such as microetectonies S-C planar joint, rotational porphyroid system, micaceous fish, unsymmetrical fold and microfolding are very clear and to be coincided with each other. The research demonstrates a normal faulting tenacity shear zone with hanging wall wcstwardly sliding according to kinematics characteristics of the tenacity shear zone. The result accords with macroscopic research and also provides powerful evidence for the overall research of the fault.