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在传统的冈底斯岩浆弧中新发现一条时代为晚三叠世的迫龙藏布蛇绿混杂岩带,并查明中侏罗世杂色砾岩角度不整合覆盖在该蛇绿混杂岩带两侧的地层之上,表明冈底斯岩浆弧中有一条印支晚期叠合的缝合带。查证了雅鲁藏布江蛇绿混杂岩带的空间展布和物质组成。雅鲁藏布江缝合带在研究区主要表现为蛇绿混杂岩,呈向NE凸的倒U字型连续分布于南迦巴瓦变质岩系和冈底斯岩浆弧之间,主要由变质的超镁铁质侵入岩、辉绿-辉长岩、玄武岩和硅质岩组成。该岩石经历了强烈的剪切变形和糜棱岩化作用,主期韧性剪切的性质为伸展拆离,变玄武岩的地球化学特征同日喀则地区蛇绿岩中的玄武岩基本相同。将南迦巴瓦岩群解体,厘定了该岩群原岩及变质峰期的时代。
In the traditional magmatic arc of the Gangdese, a new period was discovered in the Late Triassic force Longzhangbu ophiolitic melange belt and it was verified that the Middle Jurassic miscellaneous conglomerate angle unconformity covered the ophiolitic mélange On both sides of the strata, it shows that there is a late Indosinian superimposed suture in the Gangdese magma arc. The spatial distribution and material composition of the Yarlung Zangbo ophiolitic melange belt have been verified. The Yarlung Zangbo River suture zone is mainly ophiolitic melange in the studied area, and the inverted U-shaped to NE convex is continuously distributed between the Namjagbarwa metamorphic rock series and the Gangdise magma arc, which is mainly composed of metamorphic ultramafic Intrusive rocks, diabase-gabbro, basalt and chert. The rock underwent intensive shear deformation and mylonitization. The main ductile shear is characterized by extensional detachment. The geochemical characteristics of the altered basalt are basically the same as those of the basalt in the ophiolite of Shigatse. The Nanjagbarwa group was disintegrated and the age of the original rock and metamorphic peak of the group was determined.