Post-Collision Related Late Indosinian Granites of Gangdise Terrane:Evidences from Zircon U-Pb Geochronology and Petrogeochemistry
Wang Cheng
Wei Qirong
Liu Xiaonian
Ding Pengfei
Bu Tao
Sun Ji
Zhang Xiaoqiang
Wang Jingyuan
Abstract：The lithology,LA-ICP-MS zircon U-Pb age,major and trace element geochemistry,Sr-Nd-Pb isotope compositions of Dabula pluton from the middle part of the Gangdise granitoid belt are systematically studied in the paper.Results suggest that the rock type is adamellite,and the pluton is composed of middle-fine grained border facies and middle-coarse grained cen-tral facies.The two facies yield weighted mean ages of 230.6±4.3 Ma-228.2±3.5 Ma,with the corresponding age of Late Triassic.The rocks are relatively rich in SiO2 and kalium,with SiO2 content between 71.79%-77.27%;relatively high K(w (K2 O)=4.06%-5.26%)and low Ti(w(TiO2 )=0.06%-0.40%)contents;A/CNK varies from 1.16-1.19,displaying strong peraluminous characteristics and sharp negative Eu anomalies (δEu=0.06-0.35).Trace element ratio spider diagram displays apparent enrichments of Rb,Th elements,and marked depletions of Ba,Nb,Sr,P and Ti The Sr-Nd isotopes show the granite bodies have the high initial 87 Sr/86 Sr ratios (0.712 7-0.720 1)and the negativeεNd (t)(-10.6)results.Pb isotope feature shows the enrichment of radiogenic Pb.It is concluded that the Dabula pluton was formed by partial melting of mature crustal materials from Gangdise resulted from the underplating of the subduction-related basaltic magmas during the post-colli-sional extention in the dynamic background associated with the southward Bangong-Nujiang Tethyan seafloor subduction trig-gered by the collision between the northern Australia and Lhasa terranes.
Keywords：late Indosinian granitezircon U-Pb agegeochemistrypost-collisionGangdise
Publication Date：2014-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：13( 1277-1288,1300 )