滇东南老君山矿集区马卡钨铍稀有金属矿床花岗岩年代学归属  

A study on isotopic chronology of granites in the Maka W-Be polymetallic deposit of the Laojunshan ore-concentrated district,SE Yunnan, China

作　　者：杜胜江 温汉捷 张锦让 秦朝建[6] 罗重光 DU Sheng-jiang;WEN Han-jie;ZHANG Jin-rang;QIN Chao-jian;LUO Chong-guang(State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China;Guizhou Geological Survey,Bureau of Geology and Mineral Exploration and Development of Guizhou Province,Guiyang 550005,China;College of Earth Science and Resources,Chang'an University,Xi'an 710054,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;College of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China;Stake Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy Sciences,Guiyang 550081,China)

机构地区：[1]东华理工大学核资源与环境国家重点实验室,江西南昌330013 [2]贵州省地质调查院,贵州贵阳550005 [3]长安大学地球科学与资源学院,陕西西安710054 [4]中国科学院大学地球与行星科学学院,北京100049 [5]西南石油大学地球科学与技术学院,四川成都610500 [6]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵州贵阳550081

出　　处：《矿物学报》2022年第3期257-269,共13页Acta Mineralogica Sinica

基　　金：国家自然科学基金项目(编号:41962005,41903038,42073019);国家重点研发计划项目(编号:2017YFC0602500)。

摘　　要：滇东南地区处于扬子板块和华夏板块交汇处,该区地质活动频繁、成矿条件优越,分布有个旧岩体、薄竹山岩体、老君山岩体,并伴随形成了以个旧锡矿床、白牛厂银多金属矿床、都龙锡锌矿床为代表的大型-超大型矿床,构成了我国重要的滇东南钨锡多金属成矿带。马卡钨铍多金属矿床分布于老君山岩体北缘,位于重要的滇东南成矿带上,该矿床与区内的马卡花岗岩成因上具有密切联系。本文通过对马卡花岗岩LA-ICP-MS锆石U-Pb同位素年代学开展了系统研究,探讨了该花岗岩的形成年龄、物质来源等。结果显示,马卡花岗岩年龄位于400~415 Ma之间,表明其形成于加里东期,应归属于加里东期的南温河系列花岗岩系列,而不是燕山期老君山花岗岩的组成部分。马卡花岗岩具有高硅(w(SiO_(2))=72.47%~74.63%)、高碱(w(NaO_(2)O+KO_(2)O)=7.02%~7.79%)、高钾(w(KO_(2)O)>w(NaO_(2)O))、强过铝质(I_(A)/I_(CNK)>1.11)等特征,Y、Th与Rb演化趋势表明其应为S型花岗岩,综合分析,其原岩可能主要为富粘土的泥质来源。The Laojunshan ore-concentrated district,SE Yunnan,China,is located in the conjunction area of the Yangtze Block and Cathaysian Block.In this special geotectonic area,owing to recurrent geologic activities and excellent ore-forming conditions,the Gejiu,Bozhushan and Laojunshan intrusions were emplaced and a series of super-large ore deposits including representatives of the Gejiu tin deposit,the Bainiuchang silver-polymetallic deposit,and the Dulong tin-zinc polymetallic deposits were formed in association with those intrusions.These deposits constituted the SE Yunnan polymetallic tungsten-tin metallogenic belt which is an important one in China.The Maka tungsten-beryllium polymetallic deposit is located in the northern contact zone of the Laojunshan intrusion within the important SE Yunnan metallogenic belt.Its metallogenesis may be closely related to the Maka granite.In this study,we have carried out a systematical chronological study by using the LA-ICP-MS zircon U-Pb dating to discuss the formation age and materials sources of the Maka granite.The results show that the zircon U-Pb ages vary from 400 Ma to 415 Ma,indicating that the Maka granite body was emplaced in the Caledonian rather than the Yanshanian and it should belong to a part of the Caledonian Nanwenhe granite series rather than a part of the Yanshannian Laojunshan granite body.Additionally,the Maka granite samples are featured with high-silicon (w(SiO_(2))=72.47%-74.63%),high-alkali (w(Na_(2)O+K_(2)O)=7.02%-7.79%),high-potasium (w(K_(2)O)>w(Na_(2)O)),and strong peraluminous granite (I_(A)/I_(CNK)>1.11).Evolutionary trends of Y,Th,and Rb show that the Maka granite should belong to the S-type granite and could be derived from the remelt of clay-enriched argillaceous rocks.

关 键 词：锆石U-PB定年 马卡花岗岩 南温河系列花岗岩 老君山矿集区 

分 类 号：P618.72[天文地球—矿床学] P597[天文地球—地质学]