Re-Os dating of auriferous pyrite from the Zhenyuan super-large gold deposit in Ailaoshan gold belt,Yunnan Province,Southwestern China  

作　　者：SHI GuiYong SUN XiaoMing PAN WeiJian HU BeiMing QU WenJun DU AnDao LI Chao 

机构地区：[1]School of Marine Sciences,Sun Yat-sen University,Guangzhou 510275,China [2]Department of Earth Sciences,Sun Yat-sen University,Guangzhou 510275,China [3]Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering,Guangzhou 510006,China [4]National Research Center of Geoanalysis,Beijing 100037,China

出　　处：《Chinese Science Bulletin》2012年第35期4578-4586,共9页

基　　金：supported by the National Natural Science Foundation of China(40830425,40673045 and 40373027);the National Basic Research Program of China(2009CB421006 and 2002CB412610);Research Fund for the Doctoral Program of Higher Education of China(200805580031);the Project Supported by Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2011)

摘　　要：Zhenyuan gold deposit is the largest super large gold deposit in the Ailaoshan gold belt,but its precise mineralization age is still lack.Re-Os isotopic age of the auriferous pyrite from the Zhenyuan gold deposit was determined by using a high-resolution inductively coupled plasma mass spectrometry(HR-ICP-MS).The pyrite samples were decomposed in carius tubes,Os was separated by distillation and Re was extracted by acetone,respectively.The results show that the Re-Os isochron age is 229±38 Ma(MSWD=2.0,confidence level is 95%),with an initial 187 Os/188 Os value of 0.68±0.24 and a corresponding Os value of 442±91.The Re/Os ratios of the pyrite vary from 40.8 to 100.5.The data suggest that at least one important ore-forming event was occurred during Indosinian epoch,and the ore-forming materials probably derived from mixed sources of crustal and mantle,while the later dominated.The Ailaoshan composite orogen experienced complicated evolutional processes,including formation of Precambrian-Early Paleozoic basement,subduction and orogenesis of Late Paleozoic era,collisional orogenesis of Late Hercynian-Indosinain epoch,and extensional or striking orogenesis of Yanshainan-Cenozoic epoch.The polycycle tectonic evolution and magmatism in this area caused multi-stage and superposition metallization characteristics of the Zhenyuan gold deposit:the mineralization probably occur mainly during the Indosinian collisional orogeny,while the minor gold ores of altered granite-porphyry and altered lamprophyre may be formed in the late superposition metallization.Zhenyuan gold deposit is the largest super large gold deposit in the Ailaoshan gold belt,but its precise mineralization age is still lack.Re-Os isotopic age of the auriferous pyrite from the Zhenyuan gold deposit was determined by using a high-resolution inductively coupled plasma mass spectrometry（HR-ICP-MS）.The pyrite samples were decomposed in carius tubes,Os was separated by distillation and Re was extracted by acetone,respectively.The results show that the Re-Os isochron age is 229±38 Ma（MSWD=2.0,confidence level is 95%）,with an initial 187 Os/188 Os value of 0.68±0.24 and a corresponding Os value of 442±91.The Re/Os ratios of the pyrite vary from 40.8 to 100.5.The data suggest that at least one important ore-forming event was occurred during Indosinian epoch,and the ore-forming materials probably derived from mixed sources of crustal and mantle,while the later dominated.The Ailaoshan composite orogen experienced complicated evolutional processes,including formation of Precambrian-Early Paleozoic basement,subduction and orogenesis of Late Paleozoic era,collisional orogenesis of Late Hercynian-Indosinain epoch,and extensional or striking orogenesis of Yanshainan-Cenozoic epoch.The polycycle tectonic evolution and magmatism in this area caused multi-stage and superposition metallization characteristics of the Zhenyuan gold deposit：the mineralization probably occur mainly during the Indosinian collisional orogeny,while the minor gold ores of altered granite-porphyry and altered lamprophyre may be formed in the late superposition metallization.

关 键 词：RE-OS同位素年龄 超大型金矿床 含金黄铁矿 中国西南地区 哀牢山 金矿带 电感耦合等离子体质谱 碰撞造山作用 

分 类 号：P618.51[天文地球—矿床学]