老挝西北部沙耶武里地区闪长岩锆石U-Pb年代学与地球化学特征  

Zircon U-Pb Geochronology and Geochemical Characteristics of the Diorites in the Sayabouli Area,NW Laos

作　　者：刘书生[1,2] 聂飞[2] 吴振波[2] 范文玉[2] 高建华[2] 杨永飞[2] LIU Shu-sheng;NIE Fei;WU Zhen-bo;FAN Wen-yu;GAO Jian-hua;YANG Yong-fei(College of Earth Sciences,Chengdu University of Technology,Chengdu,Sichuan 610059;Chengdu Center,China-Geological Survey,Chengdu,Sichuan 610081)

机构地区：[1]成都理工大学地球科学学院,四川成都610059 [2]中国地质调查局成都地质调查中心,四川成都610081

出　　处：《地质与勘探》2018年第6期1282-1291,共10页Geology and Exploration

基　　金：中国地质调查局地质调查项目"老挝;柬埔寨及邻区矿产资源潜力评价"(编号:DD20160107)资助

摘　　要：老挝沙耶武里地区发育一套二叠纪-三叠纪岩浆岩,主要岩性为玄武岩、安山岩、流纹岩和花岗岩、二长花岗岩、花岗闪长岩和闪长岩。本文报道了老挝西北部沙耶武里地区闪长岩样品LAICP-MS锆石U-Pb年龄为253. 5±1. 5Ma(MSWD=1. 18),属早三叠世。该岩体明显富集K、Rb、Ba、Sr、Th、U等大离子亲石元素和轻稀土微量元素(LREE),Nb、Ta、Ni等高场强元素相对亏损,Nb/Ta、Th/Yb、(Th/Nb)N和Nb/La比值表明岩石成因具壳幔混合特征;结合区域地质构造演化过程综合分析得出该岩体形成的大地构造背景为古特提斯洋洋壳俯冲-岛弧环境。A set of Permian-Triassic basalts,rhyolite,granite,monzonitic granite,granodiorite,diorite assemblages outcropped in the Sayabouli area in NW Laos.This paper reports that the LA-ICP-MS zircon U-Pb age is 253.5±1.5Ma(MSWD=1.18)for the diorite sample from the Sayabouli area,which indicates the diorites were formed in the Early Triassic.These diorites are enriched in LILE(such as K,Ba,Rb),LREE and more mobile incompatible elements(such as Th,U),and are relatively depleted in HFSE(such as Nb,Ta,Ni).Combined the ratio characteristics of Nb/Ta,Th/Yb,(Th/Nb)N and Nb/La,the occurrence of Early Triassic diorites in the Sayabouli region suggests that NW Laos was dominated by a subduction-related environment.

关 键 词：闪长岩 地球化学特征 锆石U-PB年龄 

分 类 号：P5[天文地球—地质学]