ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    中亚造山带西准噶尔地区达尔布特蛇绿岩研究进展与展望

    Progress and Prospect of the Darbut Ophiolite in West Junggar, Central Asian Orogenic Belt

    • 摘要: 蛇绿岩是研究古大洋的主要载体和划分古板块边界的重要证据,记录了从大洋岩石圈的最初形成到最后洋盆闭合的诸多信息,是研究洋–陆转换过程的关键地质体。西准噶尔达尔布特蛇绿岩是北疆地区发育规模最大、最为典型的蛇绿岩带之一,相关研究近年来取得了系列成果。①在萨尔托海铬铁矿中发现金刚石等深部矿物群,从而对此前铬铁矿的浅部成矿理论提出了质疑。②在蛇绿岩中识别出前弧玄武岩,它是俯冲起始的地质记录之一。③蛇绿岩中存在古海山物质组分,其中玄武岩具有OIB特征。④萨尔托海铬铁矿是深部地幔预富集和浅部再富集的结果。⑤达尔布特蛇绿岩形成于俯冲有关的构造环境,并有地幔柱的参与。在取得进展的同时,也出现了一些新的科学问题和研究方向,主要包括深部物质循环过程、俯冲起始机制、陆壳增生机制和俯冲带型蛇绿岩成因等。

       

      Abstract: Ophiolite is a major material for studying of ancient oceans and important lithological evidence for delineating ancient plate boundaries. It records valuable information from the initial formation of the oceanic lithosphere to the final closure of the ocean basin, and is also a key geological target for studying the ocean–continent transition process. The Darbut ophiolite in West Junggar is one of the largest and most typical ophiolites exposed in northern Xinjiang. A series of new advances have been achieved in recent years: ① Diamonds and other exotic minerals have been recovered from chromitites of the Sartohay ophiolites, thus challenging the previous theory of shallow chromitite genesis. ② Fore–arc basalts have been identified in the ophiolite, which is one of the geological records of subduction initiation. ③ Ancient seamount material components have been recognized in the ophiolite, in which the basalt show OIB characteristics. ④ Sartohay chromitite is the result of deep mantle pre–enrichment and shallow re–enrichment. ⑤ A formation environment mainly associated with a subduction–related tectonic setting, with the involvement of the mantle plume, has been suggested. Despite progresses mentioned above, some new scientific issues and research directions have emerged, mainly concerning deep mantle mass recycling processes, subduction initiation mechanisms, crustal growth processes, and subduction zone ophiolite genesis.

       

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