Abstract:The gneiss from Yaolesayi in north Altyn Tagh is mainly composed of biotite monzonitic granitic gneiss.In order to find out the origin,formation age and tectonic setting of intrusive rocks in this area,studies of petrology,zircon U-Pb chronology and geochemistry were carried out.LA-ICP-MS U-Pb dating obtains the age of 927±3 Ma,corresponding to Qingbaikou period of early Neoproterozoic.We have learnt that the granite in research area is rich in silicon(SiO2=71%~73.96%)and alkali \[(Na2O+K2O)=6.61%~8.00%\].The Rittman index of the granite is 1.41~2.09,which shows a characteristic of calc-alkaline series.The aluminum oversaturated index (A/CNK)is 1.01~1.25,which is a peraluminous series.The granite is rich in LILEs such as Rb,K,Th and U and depleted in HFSEs such as Nb,Ti,P and Ta,corresponding to the features of continental collision granite.The granite is also characterized by high ∑REE,LREE enrichment,notable light and heavy REE fractionation ((La/Yb)N=7.53~8.13) and apparent negative Eu anomaly(δEu=0.40~0.68),which shows a right-leaning REE pattern in the shape of a seagull,corresponding to the features of crustal remelting granite.The granite in research area may be produced by partial melting of metamorphic sandstone. According to the regional geological data,the granite magma is proved to be a product in the late stage of syn-collision.