岩石矿物学杂志2026，Vol.45Issue(1)：93-112,20.DOI:10.20086/j.cnki.yskw.2026.5051
云南南华砷铊矿床矿物学及铊富集特征研究
Mineralogical and thallium enrichment characteristics of the Nanhua As-Tl deposit,Yunnan Province,China
摘要
Abstract
Thallium(Tl),a strategically critical metal,holds significant application value in high-tech industries.The Nanhua As-Tl deposit in Yunnan Province represents one of the few independent thallium deposits worldwide,with ore bodies occurring as stratiform layers within thin-bedded dolomite of the Upper Jurassic Series.This study systematically investigates the deposit's mineral assemblages,textural characteristics,thallium occurrence modes,and enrichment mechanisms through comprehensive field surveys,petrographic observations,and analytical techni-ques including scanning electron microscopy(SEM)and electron probe microanalysis(EPMA).The results dem-onstrate that realgar and orpiment dominate the ore minerals,with hydrothermal mineralization divisible into two sta-ges:Stage Ⅰ comprises realgar-orpiment-pyrrhotite-pyrite-(thallium minerals-chalcopyrite-galena)assemblages,while Stage Ⅱ is characterized by realgar-orpiment-thallium mineral assemblages.Stage Ⅰ realgar(Rlg1)appears as orange-yellow fine veins,contrasting with Stage Ⅱ realgar(Rlg2)exhibiting coarser orange-red veins.EPMA analyses reveal thallium primarily exists in two forms:discrete mineral phases and isomorphism.Beyond discrete thallium minerals,realgar,orpiment,pyrite,and pyrrhotite display anomalously high Tl concentrations,serving as principal carrier minerals.Pyrrhotite contains the highest Tl content(0.47％～1.89％,average 1.06％),showing strong positive correlation with As and negative correlation with Fe,suggesting coupled substitution of Fe by As3++Tl++Tl3+↔2 Fe2++Fe3+.Pyrite exhibits Tl concentrations of 0.04％～0.18％(average 0.10％)with similar ele-mental correlations,indicating direct Tl+substitution for Fe2+via 2 Tl+↔□＋Fe2+(□ representing vacancy).Real-gar contains slightly higher Tl(≤0.59％,average 0.13％)than orpiment(≤0.17％,average 0.07％),both likely incorporating Tl through isomorphism.Integrated studies suggest differential Tl enrichment correlates strongly with Tl-rich ore-forming fluids under low sulfur fugacity and reduced low-temperature conditions,identifying pyrrho-tite as a key prospecting indicator for Tl-rich resources.关键词
铊/赋存状态/组构特征/富集规律/南华砷铊矿床Key words
thallium/occurrence/textural and structural feature/enrichment law/Nanhua As-Tl deposit分类
天文与地球科学引用本文复制引用
徐萃,周家喜,罗开,胡金..云南南华砷铊矿床矿物学及铊富集特征研究[J].岩石矿物学杂志,2026,45(1):93-112,20.基金项目
国家自然科学基金项目(U2444207) （U2444207）
云南省科技厅科技计划项目(202401AW070002) （202401AW070002）
云南省新一轮找矿突破战略行动地质勘查基金科研项目(Y202409) National Natural Science Foundation of China(U2444207) （Y202409）
Science and Technology Plan Project of Yunnan Province Department of Science and Technology(202401AW070002) （202401AW070002）
Geological Exploration Fund Research Project of the New Round of Mineral Exploration Breakthrough Strategy Action of Yunnan Province(Y202409) （Y202409）
