大别造山带晚造山期花岗岩类  

Late-orogenic Granitoids(174～161 Ma) in the Dabie Orogenic Belt

作　　者：王超[1] 赵展 焦若鸿[1] 王绪诚[1] 许长海[1] 

机构地区：[1]同济大学海洋地质国家重点实验室,上海200092 [2]郑州工业贸易学校,郑州450007

出　　处：《华南地质与矿产》2010年第4期8-15,共8页Geology and Mineral Resources of South China

基　　金：国家自然科学基金项目(No.40872138)资助

摘　　要：大别造山带存在中侏罗世花岗质岩浆活动,相关花岗岩类在成分上与准铝质岩一致,其锆石U-Pb与全岩Rb-Sr年龄为174-161 Ma。这些岩体主要属于造山带中下地壳深部熔融、侵入之产物,具有晚造山挤压型花岗岩的特点。岩体出露面积与剥露深度的区域变化,主要与后期强烈的热窿伸展差异改造作用有关。大别造山带晚造山期的挤压环境,还控制合肥盆地前陆挤压阶段（中侏罗世–晚侏罗世早期）以及南北两侧逆冲推覆构造的发育。西太平洋汇聚特性的急剧变化（侏罗纪末）,是促成大别山造山根突发性拆沉事件以及区域伸展机制取代晚造山期挤压作用的根本原因,推测这种晚造山期挤压环境大致结束于-160Ma,即造山根突发性拆沉作用发生之时。The Mid-Jurassic metaluminous granitic rocks,which is yield geochronology age of 174 ~ 161 Ma by zircon U-Pb and whole rock Rb-Sr isotopic methods,is found in Dabie orogenic belt.The geochemical feature of those granitic rocks indicated that the granitic magma is from melting of lower-middle continental crust of the orogen which is triggered by late-orogenic compression.The spatial difference of exposure area and exhumation depth of those granitic rocks is mainly related to the Early-Cretaceous doming extension in Dabie orogenic belt.The late-orogenic compression of Dabie orogenic belt is also controlling the development of Mid-Jurassic to early Late-Jurassic compression of Hefei foreland basin and thrusting structures in north and south sides of the orogen.The replacement of late-orogenic compression environment by regional extension mechanism in Dabie orogenic belt is at the same time with the large-scale removal of the thickened orogenic root in ~160 Ma,both of which are caused by the rapid changes of the Western Pacific convergence feature in later Late-Jurassic.

关 键 词：花岗岩类 晚造山期挤压 热隆伸展 大别造山带 

分 类 号：P618.51[天文地球—矿床学]