西藏羌塘长蛇山辉长岩岩石学、地球化学特征及构造意义

The Petrological, geochemical characteristics and tectonic significance of Changsheshan Gabbro rock in Qiangtang, Tibet

本文采用岩石学、矿物学、地球化学和年代学等研究方法,并结合前人的研究成果,对西藏羌塘长蛇山地区北西-南东向的辉长岩成因与构造背景进行了详细的分析,发现该区辉长岩产自陆壳环境,其岩浆演化过程中存在陆壳物质的混染,这与长蛇山所在区域——玛依岗日地区内东西向基性侵入岩产出的洋中脊环境有所不同,进而推测该研究区岩墙群形成于威尔逊旋回的萌芽阶段,形成于大陆伸展背景下的初始裂谷环境,对龙木错-双湖缝合带的构造演化具有重要的制约作用,有助于深化对特提斯洋演化的认识。

Based on the petrology, mineralogy, geochemistry and chronology, such as research methods, and combining previous research results, a detailed analysis of the NW-SE gabbro structure in the changsheshan area,qiangtang, Tibet, shows that the gabbro in this area originated from the continental crust environment and was mixed with other materials during the magmatic evolution. this is different from the mid-ocean ridge environment produced by the E-W basic intrusive rocks in the area where changshe mountain is located--Mayigangri area.Therefore, it is speculated that the wall group in this study area was formed in the germination stage of Wilson cycle, The initial rift environment formed under the background of continental extension is an important constraint on the tectonic evolution of Longmuco-double lake suture zone, and helps to deepen the understanding of the foreign evolution of Tethys.