刘海永, 曾庆高, 王雨, 毛国正. 西藏拉果错蛇绿混杂岩岩石学、锆石U-Pb年龄及地球化学特征[J]. 地质通报, 2020, 39(2-3): 164-176.
    引用本文: 刘海永, 曾庆高, 王雨, 毛国正. 西藏拉果错蛇绿混杂岩岩石学、锆石U-Pb年龄及地球化学特征[J]. 地质通报, 2020, 39(2-3): 164-176.
    LIU Haiyong, ZENG Qinggao, WANG Yu, MAO Guozheng. Petrology, zircon U-Pb age and geochemical characteristics of the Lhaguo Tso ophiolitic melange in Tibet[J]. Geological Bulletin of China, 2020, 39(2-3): 164-176.
    Citation: LIU Haiyong, ZENG Qinggao, WANG Yu, MAO Guozheng. Petrology, zircon U-Pb age and geochemical characteristics of the Lhaguo Tso ophiolitic melange in Tibet[J]. Geological Bulletin of China, 2020, 39(2-3): 164-176.

    西藏拉果错蛇绿混杂岩岩石学、锆石U-Pb年龄及地球化学特征

    Petrology, zircon U-Pb age and geochemical characteristics of the Lhaguo Tso ophiolitic melange in Tibet

    • 摘要: 拉果错蛇绿岩是青藏高原中部狮泉河-纳木错-嘉黎缝合带中出露最完整的蛇绿岩组合之一,对恢复和反演该缝合带代表的洋盆演化及洋盆性质具有重要的约束意义。以拉果错蛇绿岩中的辉长岩、辉绿岩、辉绿玢岩和斜长花岗岩为研究对象,在岩石学、锆石U-Pb年代学和全岩地球化学研究的基础上,探讨了拉果错蛇绿岩的成因和构造背景,以此约束狮泉河-纳木错-嘉黎缝合带的性质。结果显示,斜长花岗岩锆石U-Pb年龄为167.8±1.7 Ma(n=24,MSWD=0.22),表明拉果错蛇绿岩形成于晚侏罗世。地球化学特征显示,拉果错蛇绿岩中辉长岩与辉绿岩端元均兼具岛弧与富集洋中脊玄武岩的地球化学性质,指示其形成于大陆弧后盆地环境。

       

      Abstract: Lhaguo Tso ophiolite is one of the most complete ophiolite combinations in the Shiquanhe-Namco-Lhari suture zone in central Tibetan Plateau, and has great significance for restoring the evolution of ocean.This paper reports petrology, zircon U-Pb chronology and geochemical characteristics of the diabases and plagiogranites to confirm the genesis and tectonic setting of Lhaguo Tso ophiolites.The zircon U-Pb dating of plagiogranite yielded an age of 167.8±1.7 Ma (n=24, MSWD=0.22), which indicates that the Lhaguo Tso ophiolite was formed in Late Jurassic.Geochemically, the gabbros and the diabases are similar to the island arc rocks and E-MORB, suggesting a continental back-arc basin environment setting.

       

    /

    返回文章
    返回