鞠耳雀热巴花岗岩体位于冈底斯中带北侧,呈近EW向分布于嘎立穷-鞠耳雀热巴-孔弄一带。岩石类型主要为似斑状黑云母二长花岗岩。花岗岩SHRIMP锆石U-Pb年龄为129 Ma,表明鞠耳雀热巴岩体形成于早白垩世。岩石为高钾钙碱性系列,据岩石地球化学、Sr-Nd同位素等特征,认为其属S型花岗岩,花岗质岩浆起源于古老上地壳物质不同程度部分重熔,源区物质具富粘土泥质岩特征。结合构造判别图解及区域类似岩体的研究,确定该岩体具后碰撞花岗岩性质,形成于从挤压体制向拉张体制过渡的构造环境。表明在早白垩世拉萨地块与羌塘地块间班公湖-怒江缝合带已由先前挤压隆升碰撞阶段转为伸展后碰撞阶段。%Juerquereba granitic pluton located in the north side of the central Gangdese belt,EW distribution of Galiq-iong-Juerquereba-Kongnong area.The main rock type is porphyaceous biotite monzogranite.The SHRIMP U-Pb dating results of zircons from granitic are 129 Ma.Which indicates that the Juerquereba granitic pluton were emplaced during the early Cretaceous.The granitoids belongs to high-K calc-alkaline rock series,according to the geochemical characteris-tics,Sr-Nd isotopic and other characteristics,show that it belongs to the S-type granites.Granitic magma originated in varying degrees of partial remelting of ancient upper crustal material,source material were the clay-rich pelitic rocks. Combine the tectonic discrimination diagrams and regional studies of similar rocks,the era of granites are considered to be of post-collisional type,the formation of the tectonic environment transitioned from the compressional system to the tensional system.In the early Cretaceous,Bangong Co&Nujiang suture zone is between the Lhasa block and Qiangtang block,which already changed from the compressional and uplifting collision stage into stentering post-collision stage.
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