摘要
成矿流体的来源是矿床学研究的重要课题之一。本文旨在通过真空击碎技术在线提取流体包裹体,对河台金矿的成矿流体来源进行示踪,为合理解释^(40)Ar/^(39)Ar年龄谱和等时线的意义提供科学依据。运用四极质谱对河台金矿石英脉样品流体包裹体中的气相成分进行分析,结果表明河台金矿成矿流体中含有大量的He、CO_2、N2、Ar及CH_4、C_2H_6等有机气体,利用N2-Ar-He和CO_2/CH_4-N_2/Ar体系对成矿流体来源进行示踪,河台金矿成矿流体气体组分处于变质水、岩浆水与大气降水之间的混合区域,这可能是变质成矿过程中混合了大气降水的结果。此外,早、中、晚三期石英脉样品中N2、CO_2和CH_4所占百分比具有明显差异,在CH_4-CO_2-N2三角图解上,三者具有完全不同的气体组分变化趋势。真空击碎分析CO2/Ar比值的变化趋势,验证了石英流体包裹体40Ar/39Ar定年实验中次生、原生包裹体先后释放次序及其对年龄结果的贡献。
The sources of ore-forming fluids have been a long-standing important topic in earth sciences. The aim of this study is to identify the source of an ore-forming fluid, differentiate fluid inclusion generations by quadrupole mass spectrometer （QMS） analysis, and provide basic support for the scientific interpretation of ^40Ar/^39Ar dating results by crushing in vacuum. The QMS analysis results indicate that the ore-forming fluids of the Hetai Gold Deposit are rich in He, CO2, N2, Ar, CH4, and C2H6. Most data points lie on a mixing line on the CO2/CH4 vs. NE/Ar diagrams, indicating that ore-forming fluids might have mixed with meteoric water during metamorphism and mineralization. Based on the gas compositions of a quartz sample measured during stepwise crushing, the NE-Ar-He triangle plot indicates that during the three periods of fluid inclusion growth, the gases trend in quite different directions. The CO2/Ar spectra support a gas release sequence from secondary to primary fluid inclusions, and contribute to the ^40Ar/^39Ar dating results.
出处
《地球化学》
CAS
CSCD
北大核心
2018年第2期141-148,共8页
Geochimica
基金
国家重点基础研究发展计划(2012CB416706)
国家自然科学基金创新群体项目(41421062)
关键词
真空击碎
四极质谱
流体包裹体
河台金矿
crushing in vacuum
quadrupole mass spectrometer
fluid inclusions
Hetai Gold Deposit
