老挝普翁金矿石英斑岩岩石化学特征及地质意义  

CHEMICAL CHARACTERISTICS AND GEOLOGICAL SIGNIFICANCE OF QUARTZ PORPHYRY ROCKS IN THE PUWENG GOLD DEPOSIT,LAOS

作　　者：郭翔宇 张春元 雷万祥 雷碧东 GUO Xiang-yu;ZHANG Chun-yuan;LEI Wan-xiang;LEI Bi-dong(Yunnan Gold Mining Group Co.,Ltd.,Kunming 650200)

机构地区：[1]云南黄金矿业集团股份有限公司,云南昆明650200

出　　处：《云南地质》2024年第S01期10-17,共8页Yunnan Geology

摘　　要：在野外地质调查的基础上,本文采用激光剥蚀电感耦合等离子质谱仪(LA-ICP-MS)对老挝阿速坡省普翁金矿区出露的石英斑岩中锆石进行U-Pb定年及微量元素分析。首次获得石英斑岩锆石U-Pb年龄248±0.58Ma,为早三叠世岩浆活动的产物。锆石稀土元素总量676.63×10^(-6)~2163.27×10^(-6),各分析点的稀土元素配分模式高度一致,均表现LREE亏损、HREE富集,具明显的Ce正异常和Eu负异常;基于锆石微量元素组合特征,通过锆石Ti温度计、结晶环境及构造背景,认为该区石英斑岩主要由陆壳浅层沉积岩熔融形成,形成于板内伸展构造背景下。Based on field geological surveys,a Laser Ablation Inductively Coupled Plasma Mass Spectrometer(LA-ICP-MS)was used to conduct U-Pb dating and trace element analysis on zircons from quartz porphyry exposed in the Puweng gold mine area,Attapeu Province,Laos.A zircon U-Pb age 248±0.58 Ma was firstly obtainedfor the quartz porphyry,indicating it is a product of Early Triassic magmatic activity.The total concentration of rare earth elements(REEs)in the zircon ranges from 676.63×10^(-6) to 2163.27×10^(-6).The REE distribution patterns ofeach analysis point was highly consistent,showing depletion in LREE and enrichment in HREE,with noticeable positive Ce anomalies and negative Eu anomalies.Based on the trace element composition and Ti thermometry of zircon,and crystallization environment and tectonic settings,it is concluded that the quartz porphyry in this area was primarily formed by the melting of shallow crustal sedimentary rocks under an intraplate extensional tectonic background.

关 键 词：LA-ICP-MS 锆石U-PB年龄 锆石微量元素 石英斑岩 普翁金矿 老挝阿速坡 

分 类 号：P588.132[天文地球—岩石学]