大别山商城—麻城断裂带的^(40)Ar-^(39)Ar年龄及其意义  

^(40)Ar-^(39)Ar Dating of the Shangcheng—Macheng Fault Belt in the Dabie Orogen and Its Significance

作　　者：王义天[1] 李继亮 刘德良[2] 吴运高 付永涛 吴峻 

机构地区：[1]中国科学院地质研究所岩石圈构造演化开放研究实验室,北京100029 [2]中国科学技术大学地球与空间科学系,合肥230026

出　　处：《地质论评》2000年第6期611-615,共5页Geological Review

基　　金：中国科学院资源与生态环境研究"九五"重大项目 (编号KZ951-A1-401-016)资助的成果

摘　　要：商城 麻城断裂带在大别山的构造格局中占有重要地位,但长期以来对其形成时代缺乏精细的测年研究,有鉴于此,我们采用断裂带糜棱岩中黑云母单矿物^(40)Ar-^(39)Ar年代学方法测定其变形时代。结果表明,商麻断裂带形成于226 Ma左右,是扬子和华北两大板块碰撞后期的产物,是一条垂直于造山带走向的横向平移断层。在商麻断裂带的转换调节下,其两侧地块发生差异位移、抬升和相对旋转,导致东西两侧的超高压岩石的折返出露呈现出不同的特征。The Shangcheng-Macheng fault belt is an important NNE-trending fault in the Dabie oro-gen, which divides the orogenic belt into two blocks: Hongan block and Dabie block. In this study, the 40Ar-39Ar dating method is employed for the biotite from the mylonite of the fault belt to determine its formation time. The result indicates that the Shangcheng-Macheng fault belt occurred around 226 Ma, which developed in the late stage of the collision between the North China plate and the Yangtze plate. The Shangcheng-Macheng fault belt is a wrench fault that is perpendicular to the orogen strike. Owing to the transforming and adjusting effects of the Shangcheng-Macheng fault belt, there occurred different displacement, uplift and relatively rotation with the Hong'an and Dabie blocks, which resulted in different exhumation characteristics of the ultrahigh-pressure metamorphic rocks in the two blocks.

关 键 词：大别山 商城--麻城断裂带 氩同位素 年代学 

分 类 号：P597[天文地球—地球化学] P542.3[天文地球—地质学]