花岗岩成矿元素迁移富集的分析方法——以滇西南大同山稀土矿区矿化与风化过程为例  

ANALYSIS MEANS FOR MIGRATION AND ENRICHMENT OF ORE-FORMING ELEMENTS IN GRANITE:Mineralization and Weathering Process of Datongshan REE Orefield in Southwestern Yunnan

作　　者：顾光明 李杭 严城民[2] 马重辉 雷星 胡凯兵 GU Guang-ming;LI Hang;YAN Cheng-min;MA Chong-hui;LEI Xing;HU Kai-bing(Yunnan Provincial Institute of Nuclear Industry Geological Survey,Kunming 650106,China;Regional Geological Survey Brigade,Yunnan Provincial Bureau of Geology and Mineral Resources,Yuxi 653100,Yunnan Province,China)

机构地区：[1]云南省核工业地质调查院,云南昆明650106 [2]云南省地质矿产勘查开发局区域地质矿产调查大队,云南玉溪653100

出　　处：《地质与资源》2024年第3期323-330,共8页Geology and Resources

基　　金：云南省地质勘查基金项目“云南省澜沧县大同山-大黑山风化壳离子吸附型稀土矿调查评价”(D202005)。

摘　　要：研究区位于滇西南临沧花岗岩中南段.为查证稀土矿体中有色金属、稀有金属的共伴生情况,在钻孔的稀土矿体中采集30件化学分析样品,分析元素为W、Sn、Nb、Ta、Rb、Cs.对花岗岩成矿元素迁移富集的研究,采用了如下方法步骤:1)将各元素的分析值由大到小顺序排列并划分为6个组,每组5个数据;进行观察后发现21件样品未发生矿化,4件样品发生过Sn矿化,4件样品发生过Rb矿化,1件样品发生过Sn、Rb矿化.2)在未发生矿化的样品中,将风化壳与未风化岩石的元素质量分数进行对比,定量评估岩石在风化过程中元素的迁移富集程度;与该地区基岩相比较,风化壳中W、Sn、Nb、Ta质量分数增高(元素富集),Rb、Cs质量分数下降(元素迁移).3)将Sn、Rb矿化样品的平均值与非矿化样品的平均值进行对比,定量评估岩石的矿化程度;发生矿化的样品平均值中,Sn矿化伴有较弱的W、Ta矿化,Rb矿化伴有明显的W、Ta、Cs矿化,Sn、Rb矿化伴生明显的W、Ta、Cs矿化.The study area is located in the middle-southern part of Lincang granite in southwestern Yunnan.To verify the coexistence condition of non-ferrous and rare metals in the rare earth element(REE)orebody,30 chemical samples are collected from the drilled orebody to analyze elements including W,Sn,Nb,Ta,Rb and Cs.The following methods and steps are adopted to study the migration and enrichment of ore-forming elements in granite:First,the analysis values of each element are arranged in order from large to small and divided into 6 groups,with 5 data in each group.Observation shows that,of the samples,21 have no mineralization,4 have Sn mineralization,4 have Rb mineralization,and one has Sn and Rb mineralization.Then,among the unmineralized samples,the element contents(in mass fraction)of weathered crust are compared with those of unweathered rocks to quantitatively evaluate the migration and enrichment degree of elements during weathering.Compared with the bedrocks in the area,the contents of W,Sn,Nb and Ta have increased(showing enrichment),while the contents of Rb and Cs have decreased(showing migration).Finally,the average values of Sn and Rb mineralized samples are compared with those of non-mineralized samples to quantitatively evaluate the mineralization degree of rocks.According to the average value of mineralized samples,Sn mineralization is accompanied by weak W and Ta mineralization,Rb mineralization by obvious W,Ta and Cs mineralization,and Sn-Rb mineralization by obvious W,Ta and Cs mineralization.

关 键 词：花岗岩 成矿元素 稀土矿 迁移富集 分析方法 云南省 

分 类 号：P618.7[天文地球—矿床学]