湘东北文家市蛇绿混杂岩带的发现及意义  

DISCOVERY OF THE WENJIASHI OPHIOLITIC MELANGE BELT IN NORTHEASTERN HUNAN AND ITS IMPLICATIONS

作　　者：贾宝华[1,2] 彭和求[2,3] 唐晓珊[2] 何江南[2] 郭乐群[2] 

机构地区：[1]中国地质大学"岩石圈构造,深部过程及探测技术"教育部重点实验室,北京100083 [2]湖南地质调查研究院,湖南湘潭411100 [3]中国地质大学地球科学学院,湖北武汉430074

出　　处：《现代地质》2004年第2期229-236,共8页Geoscience

基　　金：国土资源部国家地质调查项目 (2 0 0 0 13 0 0 0 0 2 0 71)。

摘　　要：在湘东北文家市首次识别出蛇绿岩套残片 ,它由变沉积岩、变玄武岩、变辉绿岩、变辉长岩、变辉石岩类及变硅质岩组成。综合其地质学、岩石学、地球化学和同位素年代学的资料 ,提出文家市蛇绿岩可能形成于有限小洋盆的构造环境。文家市蛇绿混杂岩带、前陆盆地、磨拉石建造和“S”型花岗岩等构造岩石组合记录了碰撞造山的全过程 ,证实了江南雪峰古陆属元古宙造山带。这一发现为华南前寒武纪的大地构造格架和地壳演化提供了依据 ,同时该地区也将成为研究早期华南大陆地壳演化———武陵运动的关键地带。This is the first report on the ophiolite suite, which consists of metasediment, meta-basalt, metadiabase, metagabbro, metapyroxene and metasilicith, in the Wenjiashi area, northeastern Hunan. Based on geology, petrology, geochemistry and isotope chronologic data issued in this work, it is suggested that the Wenjiashi ophiolite be developed under the tectonic setting of a restricted small ocean basin. Tectono-rock assemblages such as ophiolite mélange belt, foreland basin, molasse formation and 'S-type' granitoid recorded the whole process of collisional orogenesis of Wuling epoch and confirm that the Jiangnan-Xuefeng Block should belong to Proterozoic orogens. The discovery of the ophiolitic mélange belt in the Wenjiashi area provides information about the Precambrian geotectonic framework and crust evolution of South China, and therefore, this area would become one of key areas to study the early evolution (the Wuling Movement) of South China continental crust.

关 键 词：湘东北 文家市 蛇绿岩套 江南雪峰古陆 武陵运动 

分 类 号：P58[天文地球—岩石学]