Geochronology and Nd and Pb isotope characteristics of gabbro dikes in the Luobusha ophiolite, Tibet  

作　　者：ZHOU Su MO Xuanxue J.J.Mahoney ZHANG Shuangquan GUO Tieyjing ZHAO Zhidan 

机构地区：[1]China University of Geosciences(Beijing),Beijing 100083,China [2]School of Ocean and Earth Sciences and Technology,University of Hawaii.Honolulu,HI 96822,USA

出　　处：《Chinese Science Bulletin》2002年第2期143-146,共4页

基　　金：This work was supportedby both the National Natural Science Foundation of China and the National Key Project for Basic Research on the Tibetan Plateau (Grant Nos. 49772107, 49802005 and G1998040800) ; the U.S. National Science Foundation (EAR-9805318)

摘　　要：We report a combined internal and whole-rock Sm-Nd isochron age, and Nd and Pb isotopic data for gabbro dikes of the Luobusha ophiolite in Tibet. The Sm-Nd isochron of data for two whole rocks and plagioclase and clinopyroxene separates from one of the rocks yields a Middle Jurassic age of (177±31) Ma (with an initial εNd(t) = +8), which provides a significant bound on the time of formation of the Luobusha ophiolite. The Nd and Pb isotopic charac-teristics of the dike indicate an Indian-Ocean-type isotopic affinity, and we conclude that the Luobusha ophiolite formed in an oceanic setting during the Middle Jurassic.We report a combined internal and whole-rock Sm-Nd isochron age, and Nd and Ph isotopic data for gabbro dikes of the Luobusha ophiolite in Tibet. The Sm-Nd isochron of data for two whole rocks and plagioclase and clinopyroxene separates from one of the rocks yields a Middle Jurassic age of (177+/-31) Ma (with an initial epsilon(Nd)(t) = +8), which provides a significant bound on the time of formation of the Luobusha ophiolite. The Nd and Ph isotopic characteristics of the dike indicate an Indian-Ocean-type isotopic affinity, and we conclude that the Luobusha ophiolite formed in an oceanic setting during the Middle Jurassic.

关 键 词：LUOBUSHA OPHIOLITE Sm-Nd ISOCHRON age ND and Pb isotopes. 

分 类 号：P597[天文地球—地球化学]