拉孜县幅地质调查新成果及主要进展  

New results and major progress in regional geological survey of the Lhazê County Sheet

作　　者：朱杰[1,2] 刘早学 杜远生[1] 田望学 李金平 王昌平 

机构地区：[1]中国地质大学地球科学学院 [2]湖北省地质调查院,湖北武汉430074 [3]湖北省地质调查院

出　　处：《地质通报》2004年第5期471-474,共4页Geological Bulletin of China

基　　金：中国地质调查局青藏高原1:25万拉孜县幅(H45C003003)地调项目成果。

摘　　要：在雅鲁藏布江缝合带(中段)南部发现中、晚三叠世放射虫动物群,提供了该地区深水动物群新资料和混杂岩地层的年代依据。从原修康群(T3X)解体出中贝混杂岩(T2-3ZM)和破姆弄混杂岩(J3K1PM),前者形成于中—晚三叠世,后者形成于晚侏罗世—早白垩世,并由此揭示缝合带具有多旋回碰撞演化特征。冈底斯地块昂杰组(C2P1a)玄武岩的发现,表明藏南晚古生代超级冈瓦纳古大陆开始裂解。Through 1:250000 regional surveys of the Lhazê County Sheet, Tibet, the authors found the Middle-Late Triassic radiolaria fauna from cherts in the southern part of the Yarlung Zangbo suture zone (central part), which offers new data of the deep-water fauna and age evidence of the mélange (J3K1PM) in the suture zone. The Zhongbei mélange (T2-3ZM) and Pomulong mélange divorced from the original Xiukang Group (T3X) formed in the Mid-Late Triassic and the Late Jurassic-Early Cretaceous respectively. Thus the characteristics of the polycyclic collision and evolution of the suture zone are revealed. The discovery of basalt of the Angjie Formation (C2P1a) in the Gangdise block suggests that the breakup of the supercontinent Gondwana began in southern Tibet in the Late Paleozoic.

关 键 词：雅鲁藏布江缝合带 中-晚三叠世放射虫 两期混杂岩 石炭纪玄武岩 冈瓦纳大陆裂解 

分 类 号：P623.12[天文地球—地质矿产勘探]