北山金窝子金矿床流体包裹体特征及成矿流体演化  

Fluid inclusions characteristics and ore-forming evolution of Jinwozi gold deposit.

作　　者：潘小菲[1] 刘伟[1] 

机构地区：[1]中国科学院地质与地球物理研究所矿产资源重点实验室和岩石圈构造演化国家重点实验室,北京100029

出　　处：《岩石学报》2006年第1期253-263,共11页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(编号:40472056);国家重点基础研究发展规划项目(编号:2001CB409803);2005年东亚-东南亚地球科学协会(CCOP)博士论文资助基金等联合资助成果。

摘　　要：金窝子金矿床为于甘肃北山中成矿带。包裹体测温研究表明,从成矿初期到主成矿阶段,石英捕获了H_2O-NaCl,H_2O-CO_2-CH_4-NaCl,或H_2O-CO_2-NaCl体系的流体。大脉型金矿成矿初期,热液成矿流体由高温中盐度H_2O-NaCl-CO_2-CH_4四端元组份混溶的均一相热液流体；石英-黄铁矿和多金属硫化物阶段,石英捕获两成分和温度都不相同的热液组份：低盐度、富水溶液、较冷的热液和高盐度、富挥发份CO_2、CH_4和水蒸气、较热的热液。主成矿阶段石英捕获的两类型包襄体的完全均一温度相差近100℃,而且富挥发份流体盐度相对于贫挥发份流体盐度高,上述特征表明主成矿期3号脉大规模金成矿并非流体沸腾作用结果。网脉型金矿(210号脉)黄铁矿-石英成矿阶段、石英-黄铁矿和多金属硫化物成矿阶段石英捕获的地质流体的温度-成分特征无明显差异,均捕获了两种组份不同、成矿温度一致的地质流体(高盐度富水溶液流体和富堤盐度CO_2+ CH_4流体),与许多金矿的流体不混溶金成矿机制矛盾。Jinwozi Gold Deposit lies in the mid ore-forming band of Beishan Belt, Gansu Province. The analytical result of Raman spectrometric measurement for fluid inclusions in quartz shows that H2O-NaCl, H2O-CO2-CH4-NaCl, or H2O-CO2-NaCl systems are present during ore-forming processes. In Pyrite-Quartz （P-Q） stage, the Characteristics of aqueous fluid inclusions are the same as those of carbonaceous fluid inclusions in NO. 3 auriferous quartz vein. Thus, the geological hydrothermal solution showing mono-phase is unfit for deposition of gold and other heavy metals. When Quartz-Pyrite and Multi-Metal-Sulfide（ Q-P ＆ MMS） stage, homogeneous fluid fractionized into two immiscible fluid with different components and total homogenization temperature that one is low-salinity, low- temperature, aqueous fluid, and the other is high-salinity, high-temperature, CO2-rich （ and a little of CH4 ） fluid. A big difference about 100℃ in total homogenization temperature and high salinity in CO2-rich fluid are evidence of no fluid mixing process during large-scale ore deposition stages. During P-Q stage,and Q-P ＆ MMS stage in NO. 210 network auriferous quartz vein, two different hydrothermal solution, aqueous solution and low salinity and CO2 -rich （ and a little of CH4 ） fluid exist in all ore-forming stages. Thus, NO. 210 vein shows no direct relevance with immiscible mechanism. In No. 210 meshwork gold deposit controlled by pyritization mylonite, mylonitization and pyritization breccias, its homogeneous temperature and salinity of ore-forming fluid in initial stages （ P-Q ） are similar to those present in later leading ore-forming stages （Q-P ＆ MMS）, because quartz-vein formed in initial stages are altered by replacement and dissemination.

关 键 词：金窝子金矿 流体包裹体 不混溶 

分 类 号：P618.51[天文地球—矿床学]