摘要
流体包裹体可以探讨金属矿床的形成机理和矿化规律,含金石英脉是研究成矿流体的重要载体。八卦庙金矿包裹体比较发育,主要为液体包裹体、含 CO_2包裹体,其次是气体包裹体。成矿流体温度变化范围是146℃～467℃,成矿早阶段的温度为370℃～400℃;主成矿阶段的温度集中在190℃～280℃,平均约250℃;成矿晚阶段的温度集中在130℃～160℃。成矿流体包裹体类型主要为 Na^+-Cl^-型,少数属于 Ca^(2+)-Na^+-Cl^-(-SO_4^(2-)-F^-)型。计算得到流体体系的酸碱度为弱酸性(pH值=5.6～5.8),硫逸度分布范围是-9.551～-19.265(平均-15.430),氧逸度分布范围是-46.011～-40.303。金主要以[Au(HS)_2]^-的形式迁移,其次以[AuS]^-形式迁移,在成矿活动过程,随温度的下降和压力的降低,伴有沸腾-减压过程,是成矿溶液发生卸载的重要机制。
The mineralization mechanic and ore-form law of metal deposits can be discussed by fluid inclusions. Gold-bearing quartz veins are important carrier for studying ore-forming fluid. Fluids inclusions are relatively well developed in Baguamiao gold deposit. There are mainly liquid inclusions and CO2-bearing inclusions. Vapor inclusions is fewer. The metallogenic temperatures range 146 467℃ , In early Stage, the metallogenic temperatures range 370℃ -400℃. In main Stage, the metallogenic temperatures range 190℃ 280℃ with a mean of 297℃. In late Stage, the metallogenic temperatures range 130℃ -160℃. The fluid type is mainly Na^＋ -Cl^- type, a few belong to Ca^2＋ -Na^＋ -Cl^- （-SO4^2--F^- ）type. The existence form of gold is dominantly in [ Au（ HS）2 ] ^-for all the stages as a primary transportation form, with [ AuS ] ^- as a secondary form. The reduction in temperature and pressure associated with the boiling-decompression process may probably be the main mechanism for ore precipitation during its metallogenic stages.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第9期2257-2262,共6页
Acta Petrologica Sinica
基金
国家"十五"
"九五"科技攻关项目(编号:2001BA609A-06-03
96-914-03-04)
关键词
金矿
包裹体
成矿流体
八卦庙
陕西
Gold deposit, Inclusion, Ore-forming fluid, Baguamiao, Shaanxi
