川西鲜水河断裂带变形机制研究——一个浅层次高温韧性平移剪切带

STUDY OF DEFORMATION MECHANISM OF THE XIANSHUI RIVER FAULT ZONE A SHALLOW LEVEL, HIGH TEMPERATURE DUCTILE SHEAR ZONE

鲜水河断裂带位于“松潘－甘孜”造山带中部，将造山带一分为二。其大规模韧性剪切应变的揭示是基于沿断裂带花岗糜棱岩的发现。运用微观与宏观构造相结合研究方法，详细研究了鲜水河断裂带的变形机制、变形温度、变形期次、运动学特点及大规模平移作用对造山带构造格架的改造。该断裂带是一条自中新世以来具多期活动、由韧性应变向脆性应变转化的大型左行高温平移型韧性剪切带，平移总距８０－１００ｋｍ。

The Xianshui River fault zone,located in the central part of the Songpan-Garze orogenic belt,divides the belt into two parts,The revelation of extensive ductile shear strain is based on the discovery of granite mylonite along the fault zone In this paper,the authors discuss the mechanism,temperature and the phases of deformation,and then analyze the kinematic and dynamic characteristics of the Xianshui River fault zone,and its effect on the Songpan-Garze orogenic belt The Xianshui River fault zone,still active today,is a large scale high temperature left-lateral ductile shear zone which has undergone polyphase activity and transformation from ductile to brittle strain since the Miocene The displacement along the fault is over 80-100 km The large Zheduoshan granite is the syn-tectonic Product of left lateral ,ductile strike slip of the fault zone.