Abstract:Objectives:There are large-scale Linzizong Group volcanic rocks from east to west Gangdese belt.Different scholars have diverse view on the causes of its formation.The Chima Area is located in the western segment of the Gangdese belt.This paper aims to study the annual and geochemical characteristics of the Nianbo volcanic rocks in Chima Area, to supplemented relevant data andevidence of the Linzizong group volcanic rocks of the western segment of the Gangdise belt. Methods:A total of 10 samples were collected in the study area,numbered as BC2023-1,BC4022-1,BPM701-8-3,BC1803-1,BC1802-2,BC2031-1,BC1208,BC3214-2,BC4031-1,BPM271-2-2,BPM701-8-3 are both geochemistry sample and LA-ICP-MS sample,while BC1803-1,BC1802-2,BC4022-1,BC3214-2,BC2031-1 geochemistry data was cited. Zircon U-Pb isotope analysis was completed by Agilent 7500a ICP-MS instrument at the State Key Laboratory of ore deposit geochemistry,Institute of Geochemistry,Chinese Academy of Sciences. The diameter of analysis laser beam is 30μm.Standard zircon 91500 ( age 1064Ma) and GJ1 (age 600Ma) are used as external calibration,NIST SRM 610 29 Si as internal calibration.The standard error is 1Sigma.We used ICP MS Data Cal9.2 software to analyze the data,Isoplot to calculate the weighted average age and draw UPb concordia ages graph. 10 geochemical samples were completed by the Southwest Metallurgical Geology TestInstitute.The PHILLIPSPW-2404 X-ray fluorescence spectrometer was used to measure theprincipal component,its accuracy was better than 1%.Trace elements and REE elements were determined by ELEMENT-2 MS,which was better than 2% in accuracy. Results:Geochemistry analysis shows that:the rock is w(SiO2)=72.46%~81.4%,w(Al2O3)=11.39%~12.72%,Alk(K2O+Na2O)=3.33%~8.5%,w(K2O)/w(Na2O)=1.09~ 46.48,A/CNK=1.4~3.4,Rittmann indexδ=0.27~2.15.These features indicate that the rock belongs to peraluminous, potassic and ultrapotassic, calcium—alkali and alkaline rocks.Total REE content varies from 118.38×10-6~343.65×10-6,LREE/HREE=2.13~10.99,δEu=0.07~0.38,which shows enrichment of LREE and loss of HREE.The REE patterns is rightdipping.the rock has obvious negative Eu anomaly.The rock is characterized by enrichment of K、Rb、LREE and etc.LILE.and loss of Nb、P、Ti and etc.HFSE.Zircon U-Pb dating results show that volcanic rocks of the Nianbo formations was about 65~45Ma. which belongs to Paleocene and the Eocene epoch. Conclusions:the volcanic rocks of the Nianbo formationes in the study area ages was between Paleocene and the Eocene epoch, time was about 65~45Ma. The age is older than the middle and eastern segment of Gangdise, 10Ma before the eastern segment of Gangdise. The magma activity lasts longer than the volcanic rocks in the central and eastern parts of the country.mainly material sources derived from crust remelting,And they have a mixture of the mantle source, has mantle material assimilation contamination,New over time, the earth's crust material contribution to the enhanced.The volcanic rocks of the Nianbo formation in Chima area, was formed in the later stages of arcs environment, which in the tectonic setting of syn-collision and post-collision.