龙门山中央断裂运动学研究

A study on the kinematics of the Longmen central fault in Sichuan,China

龙门山造山带中央断裂是扬子地台与松潘-甘孜褶皱带的分界断层,其运动学研究具有重要意义。作者应用小构造解析的方法对龙门山中央断裂运动序列进行了解析,结果是:北段有5个运动世代,即右旋(半脆性)、逆冲、左旋正断、左旋逆冲和左旋正断;南段也有5个运动世代,但不同于北段,即韧性逆冲、右旋、逆冲、正断和左旋正断;中段同时兼具南、北段的某些特征,又具有自己的特点。龙门山中央断裂运动的时代跨越了印支期到喜马拉雅期。

The Longmen central fault is a boundary fault dividing the Yangtze Platform and the Songpan-Ganzi fold belt.A study of its kinematics is of great significance.In this paper,the structural analysis method is used to analyse the kinematics of the Longmen central fault and some meaningful results are obtained.The northern section of the Longmen central fault has experienced 5 movements,namely,the right lateral movement（by semi-brittle mode）,thrusting,left lateral movement and normal faulting,left lateral movement and thrusting,and left lateral movement and normal faulting.The southern section has also experienced 5 movements but they are unlike that of the northern section.Those are thrusting（by ductile mode）,right lateral movement,thursting,normal faulting,and left lateral movement and normal faulting.The kinemics of the middle section shows some similarities to that of both the northern and southern sections,but has its own characteristics.The time of movements is from the Indo-Sinian to the Himalayan period.