摘要
氟元素具有中等不相容性、强流体迁移性和挥发性,在岩浆作用和热液成矿等地质过程中扮演着重要角色。萤石(CaF 2)是自然界中最重要的含氟矿物之一,广泛应用于化工、航天、医药等重点领域,对国家战略安全、国民经济和社会发展有着深远影响。本文系统总结了氟的地球化学性质、在地球上不同储库中的含量及其在岩浆和热液系统中的富集成矿机制,同时探讨了全球主要萤石成矿带的大地构造背景以及萤石矿床的成因分类等问题,得出如下认识:(1)地壳和地幔是氟主要的储库,全硅酸盐地球地幔和亏损地幔中氟含量较低,而交代地幔和陆壳(包括中酸性上地壳和下地壳镁铁质麻粒岩)相对富氟,其部分熔融形成的富氟岩浆为萤石成矿提供主要物质来源;(2)国内外对萤石矿床的分类存在不同。国外学者划分了三类萤石矿床:即与碳酸岩、碱性岩或高硅花岗岩相关的岩浆萤石矿床,由断裂控制的角砾状、脉状和与地层不整合相关的构造萤石矿床,以及层控沉积萤石矿床;而国内学者则依据主要控矿要素进行类型划分,包括沉积改造型和热液充填型等类型;(3)全球大规模的萤石成矿带通常呈线性或带状分布,其成因与大洋板块俯冲作用或大陆裂谷作用密切相关;(4)热液的pH值、温度、组成、含氟矿物在其中溶解度等因素显著影响热液中氟的富集和沉淀过程。由于氟在地质样品中含量相对较低,未来研究亟需提高测试分析能力;萤石矿床的定年具有挑战性,提高萤石定年的精度与准确性亦是未来研究的重点。
Fluorine is a moderately incompatible,highly mobile,and volatile element.It plays a pivotal role in geological processes such as magmatism and hydrothermal mineralization.Fluorite(CaF 2),one of the most significant fluorine-bearing minerals in nature,is extensively used in vital fields such as chemical,aerospace and medicine.Its impact on national security,economy,and social development is profound.This paper offers a systematic summary of the geochemical characteristics of fluorine,its content in different reservoirs,and its enrichment and precipitation mechanisms in magmatic-hydrothermal systems.It also discusses the genesis and classification of fluorite deposits in combination with tectonic settings.Major understandings from the review include:(1)The crust and mantle are the primary reservoirs for fluorine.The bulk silicate earth and depleted mantle have relatively low fluorine content,while the metasomatized mantle and continental crust(including felsic upper crust and lower crust mafic granulite)are important fluorine-rich sources for the fluorite deposits.(2)There are differences in the Chinese and international classifications for fluorite deposits.Internationally,fluorite deposits have been classified into three types,i.e.,magmatic fluorite deposits associated with carbonatites,alkaline rocks or high-silica granites,structure-related fluorite deposits including breccia,vein and unconformity-related types,and strata-bound sedimentary fluorite deposits.In China,the classification including hydrothermal fluid filling and sedimentary reformation types is based on the main factors of mineralization processes.(3)Global large-scale fluorite deposits are usually linear or belt in distribution,closely related to the oceanic plate subduction or continental rifting;(4)Hydrothermal fluid pH,temperature,composition,solubility of fluorine-bearing minerals significantly affects fluorine enrichment and precipitation in the hydrothermal fluid.As fluorine is low in different geological samples,urgent research is needed to enhance the analytical techniques.Additionally,dating fluorite deposits poses challenges,therefore,improving the precision and accuracy of fluorite deposits dating remains a focus of future work.
作者
刘金宇
舒启海
张为
张方方
张玉光
陈福川
吴华英
王庆飞
邓军
LIU JinYu;SHU QiHai;ZHANG Wei;ZHANG FangFang;ZHANG YuGuang;CHEN FuChuan;WU HuaYing;WANG QingFei;DENG Jun(National Natural History Museum of China,Beijing 100050,China;State key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing 100083,China;School of Geography and Environmental Science,Guizhou Normal University,Guiyang 550025,China;Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming 650093,China;Institute of Mineral Resources Research,China Metallurgical Geology Bureau,Beijing 101300,China;State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China)
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第6期1943-1958,共16页
Acta Petrologica Sinica
基金
国家重点研发计划青年科学家项目(2023YFC2908500)资助.
关键词
氟
萤石矿床
岩浆热液系统
富集机制
Fluorine
Fluorite deposits
Magmatic-hydrothermal system
Enrichment mechanism
