藏北羌塘中部桃形湖早古生代蛇绿岩的岩石学特征  

Petrological characteristics of Taoxinghu Early Paleozoic ophiolite in central Qiangtang,northern Tibet, China

作　　者：吴彦旺[1] 李才[1] 董永胜[1] 解超明[1] 胡培远[1] 

机构地区：[1]吉林大学地球科学学院,吉林长春130026

出　　处：《地质通报》2009年第9期1290-1296,共7页Geological Bulletin of China

基　　金：国家自然科学基金项目(编号:40872146;40672147);中国地质调查局项目(编号:1212010818115)资助

摘　　要：桃形湖早古生代蛇绿岩是龙木错-双湖板块缝合带近期的重要发现。通过对桃形湖蛇绿岩进行详细的野外地质调查和岩石学、年代学、地球化学的研究发现,桃形湖早古生代蛇绿岩各单元出露齐全,由下到上分别为变质橄榄岩、超基性堆晶杂岩、堆晶辉长岩、基性岩墙群和枕状玄武岩,在堆晶岩中有不同规模的斜长花岗岩(层)脉体。桃形湖堆晶辉长岩的时代为中奥陶世,并具有大洋中脊型的地球化学特点。桃形湖早古生代蛇绿岩的发现说明龙木错-双湖板块缝合带中存在完整的蛇绿岩组合,同时也是古特提斯洋早期裂解的重要证据。Taoxinghu Early Paleozoic ophiolite is an important recent discovery in Lungmu Co-Shanghu plate suture zone. According to field geological investigation and the preliminary results of petrology, geochronology and geochemistry, we found Taoxinghu Early Paleozoic ophiolite outcrops completely, including metamorphic peridotite, ultramafic cumulate rocks, cumulate gabbro, mafic dyke swarms and pillow basalt from bottom to top, and there are different scale plagioclase granite dykes in cumulate rocks. The cumulate gabbro formed in Middle Ordovician has MORB geochemical characteristics. Taoxinghu Early Paleozoic ophiolite confirms that there is complete ophiolite in Lungmu Co-Shanghu plate suture, and it is also an important evidence for the early cracking of Paleo-Tethys Ocean.

关 键 词：羌塘中部 桃形湖 早古生代 古特提斯 蛇绿岩 

分 类 号：P534.4[天文地球—古生物学与地层学] P588.124[天文地球—地质学]