摘要
Re-Os同位素作为一种强有力的技术工具,在黑色页岩沉积时代的精确定年中得到了广泛应用。随着高精度负离子热电离质谱(N-TIMS)测试技术的发展,炭质泥岩Re-Os同位素年龄测试越来越多地被应用于厘定沉积时代。广东省大宝山铜矿成岩成矿时代争议一直是制约成因机制研究的关键因素。本文通过Carius管中逆王水溶解炭质泥岩粉末后,使用负离子热电离质谱法(N-TIMS)测试Re-Os同位素含量,获得Re-Os等时线年龄为195Ma, LA-ICP-MS碎屑锆石U-Pb年龄结果宽泛,并发育多个峰期,其中最年轻的源区岩浆锆石形成于印支期。这间接地约束了大宝山矿区侵入于侏罗系之中的英安斑岩和斑岩型铜矿的成岩成矿时代为燕山早期。同时,碎屑锆石U-Pb年龄分布特征进一步表明下侏罗统金鸡组形成于稳定大陆边缘,其碎屑物质主要来源于古老的大陆基底。
BACKGROUND: With the development of high-precision negative thermal ionization mass spectrometry(N-TIMS) technology, Re-Os isotopic dating of carbonaceous mudstone is more and more widely used in the determination of sedimentary age. The controversy over the diagenetic and metallogenic ages of the Dabaoshan copper deposit in Guangdong Province has always been a key restricting the study of the genetic mechanism.OBJECTIVES: To constrain the diagenetic and metallogenic ages of the Dabaoshan copper deposit.METHODS: Re-Os isotope ratios were determined by high precision N-TIMS after dissolving carbonaceous mudstone powder by reverse aqua regia in the Carius tube. Zircon U-Pb age was determined by laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS).RESULTS:(1) The contents of Re and Os ranged from 0.976×10;to 2.997×10;and 0.067×10;to 0.115×10;, respectively. The;Re/;Os ratio varied from 78.236 to 154.799, and the;Os/;Os ratio varied from 1.642 to 1.885. The Re-Os isotopic isochron age of black carbonaceous mudstone was 195±28 Ma(n=6, MSWD=17).(2) The;Pb/;U age ranged from 2631 to 236 Ma, including two Mesozoic zircons, accounting for 2.50% of the total zircons, 19 Paleozoic zircons, accounting for 23.8% of the total zircons, 58 proterozoic zircons, accounting for 73% of the total zircons, 1 Archean zircon, accounting for 1% of the total zircons. The results of detrital zircon U-Pb age were broad and developed multiple peak periods, among which the youngest source magmatic zircon was formed in the Indosinian period.CONCLUSIONS: The diagenetic and metallogenic age of the Dabaoshan copper deposit in Guangdong Province was constrained to the early Yanshanian. The distribution characteristics of detrital zircon U-Pb age further indicate that the Lower Jurassic Jinji Formation was formed at the stable continental margin, and its detrital material comes mainly from the ancient continental basement.
作者
刘武生
赵鸿
赵如意
秦锦华
张熊
蒋金昌
赵晨辉
李挺杰
王成辉
LIU Wusheng;ZHAO Hong;ZHAO Ruyi;QIN Jinhua;ZHANG Xiong;JIANG Jinchang;ZHAO Chenhui;LI Tingjie;WANG Chenghui(Guangdong Dabaoshan Mining Co.,Ltd.,Shaoguan 512127,China;Institute of Geological Survey,China University of Geosciences(Wuhan),Wuhan 430074,China;National Research Center for Geoanalysis,Beijing 100037,China;State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 300013,China;Key Laboratory of Mineralization and Resource Evaluation,Ministry of Natural Resources,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)
出处
《岩矿测试》
CSCD
北大核心
2022年第2期300-313,共14页
Rock and Mineral Analysis
基金
中国地质调查局地质调查项目(DD20160346,DD20190379)
东华理工大学博士启动基金项目(DHBK2019307)
科技成果转化基金项目(CGZH202102)
中央级公益性科研院所基本科研业务费项目(JYYWF20183701,JYYWF20183704)。
