滇中牟定大弯山地区新元古代变质玄武岩中Sc富集的发现及其地质意义  

Discovery of scandium enrichment and its geological significance in the Dawanshan Neoproterozoic metamorphic basalts from the Mouding area in Central Yunnan Province,China

作　　者：刘兵 周家喜[2,3,4] 孙载波 汪方跃 高雅俊[2] 宋冬虎 李小军 关奇 LIU Bing;ZHOU JiaXi;SUN ZaiBo;WANG FangYue;GAO YaJun;SONG DongHu;LI XiaoJun;GUAN Qi(Yunnan Institute of Geological Survey,Kunming 650216,China;Key Laboratory of Critical Minerals Metallogeny in Universities of Yunnan Province,School of Earth Sciences,Yunnan University,Kunming 650500,China;Yunnan Key Laboratory of Sanjiang Metallogeny and Resources Exploration&Utilization,Yunnan University,Kunming 650500,China;Key Laboratory of Sanjiang Metallogeny and Resources Exploration&Utilization,MNR,Kunming 650500,China;School of Resources and Environmental Engineering,Hefei University of Technology,Hefei 230009,China;Yunnan Planning and Design Institute of Land Resources,Kunming 650216,China)

机构地区：[1]云南省地质调查院,昆明650216 [2]云南大学地球科学学院,云南省高校关键矿产成矿学重点实验室,昆明650500 [3]云南省三江成矿作用及资源勘查利用重点实验室,昆明650500 [4]自然资源部三江成矿作用及资源勘查利用重点实验室,昆明650500 [5]合肥工业大学资源与环境工程学院,合肥230009 [6]云南省国土资源规划设计研究院,昆明650216

出　　处：《岩石学报》2023年第10期2968-2984,共17页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(91962216、42062005);云南大学科研启动项目(YJRC4201804);云南大学关键金属成矿与找矿预测创新团队项目(2021-3);中国地质调查局地质调查项目(1212011120626);云南区域地质调查片区总结与服务产品开发项目(DD20160345-02)联合资助.

摘　　要：钪(Sc)是世界各国竞相争夺的关键金属矿产资源之一。滇中牟定大弯山变质玄武岩厚度>36.5m,出露面积0.5km^(2),形成时代为新元古代南华纪(781.3±1.9Ma)。本文对该变质玄武岩开展了全岩地球化学分析、全自动矿物分析(TESCAN TIMA)观测、NPPM薄片区域面扫和单矿物原位LA-ICPMS分析等研究,结果显示变质玄武岩全岩Sc含量为47.0×10^(-6)~97.9×10^(-6),平均含量为69.1×10^(-6),钪氧化物(Sc_(2)O_(3))平均含量为106×10^(-6),变质玄武岩空间Sc矿化特征稳定,具有形成钪矿资源的潜力。同时,变质玄武岩共伴生有钛和铁矿化,全岩TiO_(2)含量为2.57×10^(-2)~6.13×10^(-2),平均为4.25×10^(-2);TFe含量为13.3×10^(-2)~23.7×10^(-2),平均为17.7×10^(-2)。Sc可能存在类质同象和离子相两种赋存形式,类质同象形式Sc主要赋存于钛铁矿和金红石矿物中,钛铁矿中Sc含量为70.0×10^(-6)~168×10^(-6),平均值为108×10^(-6);金红石中Sc含量高达297×10^(-6);而磁铁矿、黑云母等矿物中Sc含量较低,均低于全岩Sc含量,对全岩Sc矿化贡献较小。牟定大弯山Sc矿化与以往报道侵入岩及其风化壳中Sc矿化在富集特征、赋存岩性和载体矿物等方面不同,是变质火山岩中新发现的Sc矿化信息,显示了较好的找矿潜力,对Sc资源勘查和研究具有重要指示意义。Scandium(Sc)is one of the critical mineral resources that countries around the world are competing for.The Dawanshan metamorphic basalt in Mouding County,central Yunnan,has a thickness of more than 36.5m,an exposed area of 0.5km^(2),and a formation age(781.3±1.9Ma)of Neoproterozoic Nanhua Period.In this paper,the whole rocks geochemical analysis,full automatic mineral analysis(TESCAN TIMA)observation,NPPM thin section regional surface scanning and single mineral in-situ LA-ICPMS analysis were carried out for the metamorphic basalt.The results show that the Sc contents of the metamorphic basalts range from 47.0×10^(-6) to 97.9×10^(-6),with an average content of 69.1×10^(-6),and with an average scandium oxide(Sc_(2)O_(3))content of 106×10^(-6).As the Sc mineralization has stable spatial distribution characteristics,so it has the potential to form Sc deposit.At the same time,the metamorphic basalts are accompanied by Ti and Fe mineralization,with the TiO_(2) contents of 2.57%~6.13%(average 4.25%);The TFe contents range from 13.3%to 23.7%,with an average content of 17.7%.There are two types of Sc existence state:ionic phase and isomorphism phase.The Sc in the form of isomorphism mainly exists in ilmenite and rutile minerals,and the contents of Sc in ilmenite range from 70.0×10^(-6) to 168×10^(-6),with an average value of 108×10^(-6);Sc contents in rutile can up to 297×10^(-6).However,the contents of Sc in magnetite,biotite and other minerals are lower than that of the whole rocks,which makes little contribution to Sc mineralization in the whole rocks.The Dawanshan Sc mineralization in Mouding is different from the previous reported Sc mineralization in intrusive rocks and weathered rock crusts in terms of rock occurrence and mineral occurrence.It is newly discovered Sc mineralization information in volcanic rocks,demonstrating good prospecting potential,which has important guiding significance for the exploration and research of Sc deposits.

关 键 词：钪 富集特征 赋存状态 地质意义 变质玄武岩 新元古代 滇中 

分 类 号：P612[天文地球—矿床学] P618.73[天文地球—地质学]