简论龙门山南段末端地区构造发展史

A BRIEF DISCUSSION ON THE TECTONIC EVOLUTIONAL HISTORY OF TERMINAL REGION AT THE SOUTH SECTION IN LONGMEN MOUNTAINS,SICHUAN PROVINCE

龙门山南段末端地区是龙门山推覆构造带、康滇南北带和北西向甘孜地槽褶皱带交接地区。对其区域构造变形特征、前陆盆地沉积特征及基底杂岩构造特征的研究表明:该区推覆构造变形、动力变质作用都是与印支期、喜马拉雅期的构造挤压和燕山期的伸展作用相关的。龙门山构造与康滇南北带在印支期前及印支期是同一个基底和构造单元。甘孜地槽褶皱带在喜马拉雅期局部推覆到龙门山构造带和康滇南北带之上。这一发展历史确定了龙门山南段末端现存构造格局。

This is a junction region between the Longmen Mountain thrusting nappe zone, Kang-Dian N-S tectonic zone and Ganzhi NW geocynclinal folded zone. Recent research of the foreland basin sediments, regional structural deformation and tectonics of Basement Complex shows that thrusting nappe deformation and dynamic metamorphism of this region are closely related to the compression during Indosinian and Himalayan movements and evolution of Yianshan movement. There were the same basement for the Longmen Mountain tectonic zone and Kang-Dian N-S zone and once belonged to one tectonic unit. At the stage of Indosinian orogeny and before Ganzhi NW geocynclinal folded zone was partly thrusted and napped above both the Longmen Mountain and Kang-Dian N-S zone. This evolutionary history controled the tectonic style of this terminal region of the south section of Longmen Mountains.