豫西杨山萤石矿稀土元素地球化学特征及其指示意义  

Geochemical Characteristics and Indicative Significance of Rare Earth Elements in Yangshan Fluorite Deposit in Western Henan Province

作　　者：冯绍平 汪江河 刘耀文 梁新辉 黄岚 张争辉 肖贺忠 FENG Shao-ping;WANG Jiang-he;LIU Yao-wen;LIANG Xin-hui;HUANG Lan;ZHANG Zheng-hui;XIAO He-zhong(First Survey Institute of Geology and Mineral Resources of Henan Geo-exploration and Mineral Development Bureau,Luoyang 471023,China;Gold and Silver Polymetallic Metallogenic Series and Deep Prediction Key Laboratory in Henan Province,Luoyang 471023,China)

机构地区：[1]河南省地质矿产勘查开发局第一地质矿产调查院,河南洛阳471023 [2]河南省金银多金属成矿系列与深部预测重点实验室,河南洛阳471023

出　　处：《稀土》2020年第5期50-58,共9页Chinese Rare Earths

基　　金：河南省地矿局局管地质科研类项目(2018-03)。

摘　　要：通过对杨山萤石矿的地质背景、围岩及萤石稀土元素地球化学特征进行系统研究,结果表明,萤石的稀土配分型式属于重稀土富集型,表现为轻稀土向右缓倾、重稀土向左倾曲线,形态基本一致,但与围岩稀土配分型式存在明显不一致。不同颜色的萤石均具有负Eu异常特征,指示该矿床萤石沉淀时成矿流体为成矿温度较低的还原环境;存在不明显的Ce负异常,可能是成矿流体本身就存在Ce亏损,易形成萤石矿的负Ce异常,与区内合峪花岗岩体的δCe值相似,揭示了成矿流体具有一致的来源,部分成矿物质来源可能来自合峪岩体。根据Y/Ho-La/Ho关系图,杨山萤石稀土元素数据投点呈几乎水平分布的特征,Y/Ho比值介于31.59~37.39之间,明显大于28,指示矿床的成矿流体可能具有一致的富F流体来源。综合矿床地质特征、Y/Ho-La/Ho关系图、Tb/La-Sm/Nd关系图、Tb/Ca-Tb/La关系图,杨山萤石矿床中不同颜色的萤石矿表现为硅化萤石→紫色萤石→绿色萤石→浅(白)色萤石结晶演化的趋势,在形成时间存在一定微小的差异。根据Tb/Ca-Tb/La关系图及La+Y-Y/La关系图,杨山萤石矿床为岩浆热液型萤石矿床,与花岗岩的侵入有着密切的关系。The geological background,surrounding rocks and the geochemical characteristics of rare earth elements of fluorite in Yangshan fluorite deposit are studied systematically.The results show that the distribution type of fluorite belongs to the heavy rare-earth enrichment type with the curve of light rare-earth slant to the right and heavy rare-earth slant to the left.The fluorite of different colors has negative Eu anomaly,which indicates that the ore-forming fluid is a reductive environment with low ore-forming temperature when the deposit was precipitated.There is slightly negative anomaly of Ce,which may be due to the fact that the ore-forming fluid itself has Ce deficit and is prone to forming the negative Ce anomaly of fluorite ore,and is similar to the delta Ce value of Heyu granite-body in the area,revealing that the ore-forming fluid has a consistent source,and some ore-forming materials may come from Heyu rock mass.According to the Y/Ho-La/Ho diagram,the rare earth element data bits of Yangshan fluorite have almost horizontal distribution characteristics with the Y/Ho ratio between 31.59~37.39,significantly more than 28,indicating the metallogenic fluid may come from a consistent source of rich F fluid.Based on the geological characteristics of the deposit,Y/Ho-La/Ho relation,Tb/La-Sm/Nd relation and Tb/Ca-Tb/La relation,the different colored fluorite in Yangshan fluorite deposit shows that the trend of crystal evolution of silicified fluorite→purple fluorite→green fluorite→light(white)fluorite,is related to a slight difference in the formation time.According to the Tb/Ca-Tb/La diagram and La+Y-Y/La diagram,the Yangshan fluorite deposit is a magmatic hydrothermal fluorite deposit,which is closely related to the invasion of granite.

关 键 词：稀土元素 地球化学 萤石 杨山 

分 类 号：P595[天文地球—地球化学] P575[天文地球—地质学]