摘要
位于扬子地台北缘的武当推覆体是南秦岭造山带的重要组成部分，它经历了漫长的构造演化历程。该区的层固性结构和加里东—晋宁期的伸展滑脱作用造成了武当群构造堆垛岩系的形成，华北板块和扬子板块在印支运动期间的会聚、碰撞造山作用使武当巨型推覆体逐渐形成，至喜山运动时期完全定位。本文分析了这些构造运动所产生的变形效应及构造变形的复合关系，揭示了本区变形环境由低温高压或高应变速率环境向中温低压及低温低压过渡的特征，阐述了武当推覆体的形成、武当群岩系的变形效应与动力作用方式、变形岩石的边界条件、变形岩石的结构构造以及力学性质的关系，把武当群的形成、武当推覆体的演化分为三期五个阶段，其构造变形的主要动力来源为沿大陆边坡的重力滑动和陆－陆碰撞的挤压作用，其应力作用方式为由上述动力所产生的近南北向伸展和近南北向挤压两大地应力场的转化。
udang area, the eastern part of the Southern Qinling Orogen, is located on the northmargin of the Yangtze Platform, and has undergone completed tectonic deformation and evolution. Its bedding circle texture and imbricate structure resulted from ductile bedding decouplingunder extension with the upper moving to the north and from thrusting under the collision between tile N. China and S. China plates with the north side up southwards, respectively. Theformer propuced ductile bedding shear zones with mylonites and intense foliation transformationof S1 and S2, folded layers and stacked series. The latter brought about asymmetrical reversedfolds, S3 and S4 foliation, thrust sheets, ductile-brittle shearing and brittle faulting, so as to formthe Wudang Nappe. Rock deformation is related to the properties, texture and structure of rocks,find also to deformation environment, which transformed from extension to compression duringthe tectonic evolution in this area.
关键词
构造变形
推覆体
武当地区
秦岭造山带
structural deformation and tectonic compound, layer circle texture, thrust nappe,Wudang area, the southern Qinling orogen
