黔北遵义二叠纪沉积碳酸锰矿中稀土元素富集过程  

Enrichment process of rare earth elements in Permian sedimentary manganese carbonate deposits from the Zunyi area,northern Guizhou

作　　者：徐海 高军波[2,3] 杨瑞东[2,3] 徐进鸿 刘志臣[2,6] 谯文浪 叶飞[7] 张旭 XU Hai;GAO Junbo;YANG Ruidong;XU Jinhong;QIAO Wenlang;LIU Zhichen;YE Fei;ZHANG Xu(Institute of Resources and Environment,Tongren University,Tongren,Guizhou 554300,China;College of Resources and Environmental Engineering,Guizhou University,Guiyang,Guizhou 550025,China;Key Laboratory of Karst Georesources and Environment,Ministry of Education,Guizhou University,Guiyang,Guizhou 550025,China;Institute for Fanjingshan National Park,Tongren University,Tongren,Guizhou,554300,China;State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang,Guizhou 550081,China;102 Geological Team,Guizhou Bureau of Exploration and Development of Geology Mineral Resources,Zunyi,Guizhou 563003,China;103 Geological Team,Guizhou Bureau of Exploration and Development of Geology Mineral Resources,Tongren,Guizhou 554300,China;School of Ocean Science,Sun Yat-sen University,Zhuhai,Guangdong 519082,China)

机构地区：[1]铜仁学院资源与环境研究所,贵州铜仁554300 [2]贵州大学资源与环境工程学院,贵州贵阳550025 [3]贵州大学喀斯特地质资源与环境教育部重点实验室,贵州贵阳550025 [4]铜仁学院梵净山国家公园研究院,贵州铜仁554300 [5]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 [6]贵州省地矿局102地质大队,贵州遵义563003 [7]贵州省地矿局103地质大队,贵州铜仁554300 [8]中山大学海洋科学学院,广东珠海519082

出　　处：《地质学报》2025年第4期1312-1331,共20页Acta Geologica Sinica

基　　金：国家重点研发计划项目(编号2022YFC2903403);国家自然科学基金项目(编号42362014,42163006,42462008);贵州省科技计划项目(编号黔科合基础-ZK[2023]一般463、黔科合基础-ZK[2024]一般684);贵州省教育厅高等学校科学研究青年项目(编号黔教技[2022]349号,黔教技[2022]350号);贵州省地质矿产勘查开发局重大科研项目(编号黔地矿科合[2021]03);铜仁学院博士科研启动基金(编号trxyDH202214);铜仁市博士人才科技计划项目(编号铜市科研(2024)3号);喀斯特地质资源与环境教育部重点实验室(编号贵州大学)开放基金(编号KST202203)联合资助的成果。

摘　　要：稀土元素及钇(REY)作为国家战略性关键金属矿产资源长期以来备受学界关注。近年来,国外相继报道了许多沉积型锰矿显著富集REY(>500×10-6),然而关于沉积型锰矿中REY富集的物源、赋存载体及富集过程等仍缺乏精确约束。值得关注的是,笔者及课题组通过对遵义锰矿床中稀土元素组成分析发现遵义锰矿普遍富集REY,矿石及底部凝灰质黏土岩中REY平均总量分别可达658×10-6和1465×10-6,并主要以富集La、Ce、Nd及Y为特征,系我国首个报道的含稀土沉积碳酸锰矿床。遵义锰矿底部矿层中发育热液角砾状锰矿石,矿石中可见独居石脉穿插,结合矿石具有类似于底部凝灰岩REY分异特征等表明,锰矿中的REY来源于峨眉山大火成岩省(ELIP)岩浆活动相关的热液系统。锰矿中REY主要以磷酸盐的形式存在,矿石及凝灰质黏土岩中REY分别以独立稀土矿物(独居石及磷钇矿)和含稀土磷酸盐(磷铝锶石)为主要赋存载体。矿石中独居石和磷钇矿主要呈细粒(<10μm)散点状与菱锰矿及铁菱锰矿等自生矿物共生,并与菱锰矿内部少量的残余铁锰氧化物及蚀变凝灰岩矿物紧密共存。同时凝灰质黏土岩中磷铝锶石呈微晶颗粒状或胶体状与伊利石和石英等细粒矿物紧密共生,且局部可见蚀变火山碎屑残余物。上述特征记录了在早期成岩-蚀变作用过程中REY由铁锰氧化物及凝灰岩中转移进入磷酸盐的过程。综上所述,本文认为遵义锰矿中REY富集受ELIP古构造-岩浆-热液、多种赋存载体及多沉积阶段等因素共同控制,其中REY最初可能赋存于铁锰氧化物及凝灰岩中,而后在早期成岩-蚀变过程中转移至磷酸盐中形成自生(含)稀土磷酸盐矿物。As strategic and critical minerals,rare earth elements and yttrium(REY)have long been of great concern.Recent studies have reported that numerous sedimentary manganese(Mn)ores are significantly enriched in REY(>500×10-6).However,the source,carriers,and enrichment process of the REY in sedimentary Mn ores remain poorly constrained.Notably,careful compositional analyses have revealed substantial REY enrichment in the Zunyi Mn deposits.Specifically,the averageΣREY content in the ores and the underlying tuffaceous clay is 658×10-6 and 1465×10-6,respectively,which is mainly characterized by the enrichment of La,Ce,Nd,and Y,and is the first reported REY-bearing carbonate Mn deposits in China.The lower ore-bed developed hydrothermal brecciated Mn ores,and monazite veins crosscut rhodochrosite were observed in Mn ores,and coupled with Mn ores has REY fractionation characteristics similar to the underlying tuff,indicate that the enrichment of Mn and REY primarily originated from the magmatic-hydrothermal system of the Emeishan Large Igneous Province(ELIP).The REY in Mn ores and tuffaceous claystone mainly occurs as monazite,xenotime,and goyazite,indicating phosphate minerals as the principal REY carriers in the Zunyi Mn deposits.Monazite and xenotime are mainly fine-grained(<10μm)anhedral particles form,coexisting with authigenic minerals(e.g.,rhodochrosite and capillitite),and closely symbiosis with residual Fe-Mn oxides and altered tuffs within rhodochrosite.Meanwhile,goyazite appears in microcrystalline or colloidal form,closely symbiosis with fine-grained minerals(e.g.,illite and quartz),and locally coexisting with residual altered volcanic debris.In conclusion,we suggest that the REY enrichment was controlled by ELIP paleotectono-magmahydrothermal activity,multiple carriers,and multiple sedimentary stages.REY initially occurs in Fe-Mn oxide and tuff and then transfers to phosphate minerals during the early diagenesis-alteration process.

关 键 词：REY富集 含稀土磷酸盐 碳酸锰矿床 二叠纪 遵义 

分 类 号：P618.32[天文地球—矿床学]