张越, 陈隽璐, 孙吉明, 唐卓, 李平, 白建科. 新疆东准噶尔阿尔曼太蛇绿岩中玄武岩地球化学特征及其地质意义[J]. 地质通报, 2019, 38(9): 1431-1442.
    引用本文: 张越, 陈隽璐, 孙吉明, 唐卓, 李平, 白建科. 新疆东准噶尔阿尔曼太蛇绿岩中玄武岩地球化学特征及其地质意义[J]. 地质通报, 2019, 38(9): 1431-1442.
    ZHANG Yue, CHEN Junlu, SUN Jiming, TANG Zhuo, LI Ping, BAI Jianke. Geochemical characteristics and geological significance of basalt in the Armantai ophiolite, east Junggar, Xinjiang[J]. Geological Bulletin of China, 2019, 38(9): 1431-1442.
    Citation: ZHANG Yue, CHEN Junlu, SUN Jiming, TANG Zhuo, LI Ping, BAI Jianke. Geochemical characteristics and geological significance of basalt in the Armantai ophiolite, east Junggar, Xinjiang[J]. Geological Bulletin of China, 2019, 38(9): 1431-1442.

    新疆东准噶尔阿尔曼太蛇绿岩中玄武岩地球化学特征及其地质意义

    Geochemical characteristics and geological significance of basalt in the Armantai ophiolite, east Junggar, Xinjiang

    • 摘要: 阿尔曼太蛇绿岩带位于新疆东准噶尔地区,蛇绿岩中变质橄榄岩、堆晶岩、基性火山岩较发育,层序组合虽受构造破坏,但从总体来看仍是一套组合比较完整的蛇绿岩,岩石变形变质强烈,普遍发生绿泥石化、绿帘石化。蛇绿岩中基性熔岩可分为3种类型,即洋岛玄武岩(OIB)、洋中脊玄武岩(MORB)和岛弧玄武岩(IAT)。其中洋岛玄武岩不属于蛇绿岩成分,是后期卷入蛇绿岩带随其他组分一同构造就位而成;基性熔岩主量和微量元素特征揭示岩浆源于亏损的地幔源区,且存在消减组分加入的交代作用,表明其成因与俯冲作用有关。结合岩石地球化学特征和构造环境判别图解,基性熔岩显示出IAT和MORB兼具并呈现过渡的特点,推断该蛇绿岩的形成与岛弧相关,其形成可能介于洋脊到海沟之间的偏海沟区域。

       

      Abstract: The Armantai ophiolite belt is located in the east Junggar basin of Xinjiang. Metamorphic peridotite, cumulate rocks and basic volcanic rocks in the ophiolite belt are extensively developed. In spite of the fact that the sequence combination has been damaged by the structure, it on the whole remains a set of ophiolites with relatively complete assemblage. The rocks were deformed and experienced strong metamorphism, and have generally experienced chloritization and epidotization. The basic lava of Armantai ophiolite can be divided into three types, i.e., oceanic island basalt, oceanic ridge basalt and island arc basalt. Among them, oceanic island basalt did not belong to the ophiolite composition, it was involved in ophiolite belt at a later stage with other components into tectonic emplacement. The characteristics of major elements and trace elements of the basic lava show that the magma was derived from the depleted mantle and experienced metasomatism with the addition of the components of subduction zone. It is shown that its was related to the subduction. Combined with the tectonic setting and geochemical diagrams, the basic lava shows both IAT and MORB features and has the transitional characteristics. It can be inferred that the formation of the ophiolite was related to island arcs, and it probably occurred in partial oceanic trench region between oceanic ridge and oceanic trench.

       

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