变质改造型关键金属矿——富集Li-Rb-Cs-Tl-Ga的云母片岩  

Metamorphic transformation type critical metal ore:Li-Rb-Cs-Tl-Ga enriched mica schist

作　　者：高利娥[1] 曾令森[1] 赵令浩[2] 严立龙 李广旭[1] 邸英龙 徐倩 王亚莹[1] 王海涛 田怡红 GAO Li-e;ZENG Ling-sen;ZHAO Ling-hao;YAN Li-long;LI Guang-xu;DI Ying-long;XU Qian;WANG Ya-ying;WANG Hai-tao;TIAN Yi-hong(Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;National Research Center for Geoanalysis,Chinese Academy of Geological Sciences,Beijing 100037,China;School of Geographic and Environmental Sciences,Tianjin Normal University,Tianjin 300387,China)

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国地质科学院国家地质实验测试中心,北京100037 [3]天津师范大学地理与环境科学学院,天津300387

出　　处：《岩石矿物学杂志》2023年第1期29-46,共18页Acta Petrologica et Mineralogica

基　　金：国家重点研发计划(2021YFC2901901);国家自然科学基金项目(41873023,92055202,42002071);第二次青藏高原科学考察项目(2019QZKK0702);中国地质调查局地质调查项目(DD20221817,DD20221630)。

摘　　要：关键金属矿产是国际上最近提出的资源概念,对战略性新兴产业的发展至关重要,但认知程度较低。洛扎岩浆-变质杂岩体位于喜马拉雅带东部,侵位于藏南拆离系内。在岩体东北侧,云母片岩被含电气石淡色花岗岩捕虏。云母片岩主要由金云母、绿泥石和少量黑云母组成。从全岩地球化学成分来看,云母片岩具有含量较高的Al2O3(13.38%~14.32%)、K2O(6.09%~9.66%)、FeO^(*)(27.11%~30.09%)、MgO(15.25%~17.21%)、TiO_(2)(0.09%~0.26%),富集关键金属Li(650×10^(-6)~1031×10^(-6))、Rb(1649×10^(-6)~2773×10^(-6))、Cs(98×10^(-6)~229×10^(-6))、Tl(5.7×10^(-6)~12.1×10^(-6))、Ga(121×10^(-6)~148×10^(-6))。单矿物化学成分分析结果表明,金云母与全岩相似,也富集Li-Rb-Cs-Ga,这些关键金属元素以类质同象形式替代K进入金云母。年代学分析结果显示,锆石记录了分布广泛的碎屑年龄和新生代的变质事件。通过研究认为,洛扎地区云母片岩的原岩为沉积岩,在淡色花岗岩侵位过程中被捕虏,发生了低级变质作用;本文报道的金云母成矿作用,是锂矿成因的新类型:变质改造型。喜马拉雅造山带变沉积岩富集稀散金属铊和镓,表明该地区除了稀有金属元素外,稀散金属也有成矿潜力,是我国未来关键金属矿产勘探的又一重要地区。本文为建立喜马拉雅造山带关键金属的成矿模型提供了新的思路,未来需要加强该区和其他造山带变沉积岩关键金属成矿潜力的调查和研究。Critical metal minerals are recently proposed resource concept worldwide and are important to the development of strategic industries,but the level of awareness is still low.The Luozha pluton is located in the east of the Himalayan belt and invaded the Southern Tibet detachment system.On the northeast of this pluton,mica schist is captured by the tourmaline-bearing leucogranite.The mica schist is mainly composed of phlogopite,chlorite and mino biotite.Whole-rock element geochemical data indicate that the mica schist contains higher Al2O3(13.38%~14.32%),K2O(6.09%~9.66%),FeO^(*)(27.11%~30.09%),MgO(15.25%~17.21%),TiO_(2)(0.09%~0.26%),and is enriched in Li(650×10^(-6)~1031×10^(-6)),Rb(1649×10^(-6)~2773×10^(-6)),Cs(98×10^(-6)~229×10^(-6)),Tl(5.7×10^(-6)~12.1×10^(-6)),Ga(121×10^(-6)~148×10^(-6)).The geochemical data of phlogopite show that similar to the whole rock,phlogopite also is enriched in Li-Rb-Cs-Ga,and these critical metal elements are incorporated into phlogopite by replacement of K.Chronological data indicate that zircon records widespread detrital age and Cenozoic metamorphic events.Therefore,it can be concluded that the original rock of mica schist in the Luoza area is sedimentary rock,which was captured during the invasion of leucogranite and underwent low-level metamorphism.The phlogopite mineralization reported in this paper is a new type of lithium ore genesis:metamorphic transformation type.The discovery of the metals thallium and gallium in the Himalayan orogenic belt suggests that critical metals also have mineralization potential in addition to rare metals.Our data suggest that the Himalayan belt is another important target area for the exploration of critical metals.This paper provides new ideas for establishing metallogenic models of critical metals in the Himalayan orogenic belt.It is necessary to strengthen the exploration of critical metals in sedimentary or metasedimentary rocks in the Himalayan orogenic belt and the other orogenic belts in the future.

关 键 词：关键金属元素 Li-Rb-Cs-Tl-Ga 金云母 变质作用 沉积岩 喜马拉雅造山带 

分 类 号：P588.344[天文地球—岩石学] P618.7[天文地球—地质学]