胶东大磨曲家金矿床成矿流体成分及稳定同位素研究  

ORE FLUID CHEMICAL EVOLUTION AND STABLE ISOTOPE COMPOSITION OF DAMOQUJIA GOLD DEPOSIT IN SHANDONG PROVINCE

作　　者：郭春影[1] 杨立强[1] 张静[1] 高帮飞[1] 王庆飞[1] 于海军[1] 

机构地区：[1]中国地质大学北京)地质过程与矿产资源国家重点实验室

出　　处：《矿物岩石》2008年第3期51-56,共6页Mineralogy and Petrology

基　　金：国家自然科学基金(No.40572063和No.40672064);教育部创新团队、“111”计划(No.B07011);教育部“跨世纪人才培养计划”及中国地质大学地质过程与矿产资源国家重点实验室开放基金(No.GPMR0732)

摘　　要：通过对大磨曲家金矿床不同类型矿石、蚀变岩中石英单矿物流体包裹体群体气液相成分,探讨金成矿流体由高温到低温流体成分演化与金成矿过程,结果证实:流体包裹体气相成分以H2O为主,其次为CO2,其余为CH4,C2H6,H2S,少量样品检测到少量N2和Ar2。流体包裹体液相成分中,阳离子主要为Na+和K+,Ca2+次之,少数样品检测到Mg2+;阴离子主要为Cl-和SO42-,F-含量也较高。高温阶段CO2含量缓慢降低,CH4+C2H6总量变化较大;低温阶段CO2含量快速降低,H2S含量缓慢降低,CH4+C2H6总量呈现增加趋势。由高温阶段到低温阶段K+含量降低,Na+含量增加,Ca2+变化不明显;阴离子组成SO42-含量急剧降低,F-含量缓慢增加,Cl-含量快速增加。成矿流体稳定同位素组成δD水(SMOW)为-106.48‰^-95.52‰,δ18O石英(SMOW)为10.64‰~12.68‰,换算与之平衡δ18O水(SMOW)为1.88‰~5.78‰,δ13CCO2(PDB)为-6.264‰^-4.271‰。稳定同位素组成说明大磨曲家金矿床成矿流体可能为深部来源,可能与地幔排气和矿区内煌斑岩岩浆活动有关。Bulk volatiles and ions and stable isotope compositions of inclusion fluids in quartz of altered granitoids from Damoqujia gold deposit were studied in order to reveal gold ore fluid evolution and to trace its possible sources. It was showed that bulk inclusion fluid volatiles were dominated by H2O and CO2, with small amount of CH4,C2H6,H2S,N2 and Ar2. K^＋ and Na^＋ are the dominant cations in inclusion fluid with minor Ca^2＋ and Mg^2＋. Cl^- , SO4^-2 and F^- showed relative high concentrations among detected anions. From 500 ℃ to 260 ℃, CO2 content decreased slowly, H2S content increased rapidly, and CH4 ＋ C2 H6 content was relatively stable. From 260 ℃ to 100 ℃, CO2 content decreased rapidly, H2S content increased less rapidly, and CH4 ＋C2H6 content also increased. From 500 ℃ to 100 ℃, K^＋ concentration of inclusion fluid decreased, Na^＋ concentration increased, while Ca^2＋ showed no obvious change. For anions, from 500 ℃ to 100 ℃, SO4^2- concentration dropped rapidly,Cl^- concentration increased rapidly, and F concentration showed slow increase. δDH2O （SMOW） of inclusion water were -106.48‰～-95. 52‰. δ18OQartz （SMOW） were 10.64‰～12.68‰. The water δ^18O （SMOW） supposed to be balanced with quartz were ranged from 1.88‰ to 5.78‰.δ^13CCO2 （PDB） of inclusion fluid were -6. 264‰～-4. 271‰. Stable isotope compositions reflected an ore fluid source of mantle probably related to lamprophyre magma activities in the ore field.

关 键 词：胶东 金矿床 大磨曲家 流体包裹体 气液相成分 稳定同位素 

分 类 号：P618.51[天文地球—矿床学]