矿床地质2025，Vol.44Issue(3)：537-558,22.DOI:10.16111/j.0258-7106.2025.03.002
大兴安岭南段拜仁达坝Ag-Pb-Zn多金属矿床矿相学特征与银的赋存状态及沉淀机制
Mineral characteristics,silver occurrence state and enrichment mechanisms of Bairendaba Ag-Pb-Zn polymetallic deposit in southern Great Xing'an Range
摘要
Abstract
The Bairendaba is a typical large and super-large Ag polymetallic deposit in southern Great Xing'an Range.Field observation and ore mineralogy studies reveal two-stage hydrothermal mineralization in the Bairendaba de-posit:(Ⅰ)Cu-Pb-Zn polymetallic sulfides-quartz-fluorite stage and(Ⅱ)Ag polymetallic sulfides-quartz-calcite stage.To determine silver occurrence state and enrichment mechanism in the deposit,SEM-EDS and EPMA were performed on ore minerals.The results show that the silver minerals in the deposit are mainly precipitated in the stage-Ⅱ,and silver mainly occurs as various independent silver minerals,followed by the micro-submicroscopic silver(diaphorite)as anhedral granular or fine-grained immiscible solution occurs in galena,and a small amount of isomorphic silver occurs in sulfides such as stannite,galena and chalcopyrite.Combined with previous fluid in-clusion studies of the deposit,it was found that,Ag+began to combine with Cu+,Pb+,Sb3+and other metal ions in the solution when the temperature dropped to about 200℃,and directly precipitated or replaced the early sulfides to form freibergite(＜170℃).With the ore-forming fluid evolved further and the decrease of temperature,the Ag+gradually increased while Cu+decreased,the diaphorite,pyrargyrite,stephanite and argentite were formed succes-sively.When Ag+was nearly exhausted in the system,minerals such as boulangerite and non-silver galena gradu-ally precipitated.In general,the decrease of hydrothermal temperature and the increase of pH value control the precipitation sequence of ore minerals,silver occurrence state and the species of silver minerals in Bairendaba de-posit.关键词
银的赋存状态/富集机制/银多金属矿床/拜仁达坝矿床Key words
silver occurrence state/enrichment mechanisms/Ag polymetallic/Bairendaba deposit分类
地质学引用本文复制引用
杨沙沙,曹明雨,苏慧敏,密文天,胡子付,李耿,李海东..大兴安岭南段拜仁达坝Ag-Pb-Zn多金属矿床矿相学特征与银的赋存状态及沉淀机制[J].矿床地质,2025,44(3):537-558,22.基金项目
本文得到内蒙古自治区自然科学基金青年基金(编号:2024QN04002和2024QN04006)和内蒙古科技厅中央引导地方科技发展资金项目(编号:2022ZY0084)联合资助 （编号:2024QN04002和2024QN04006）
