东天山马庄山金矿床流体包裹体和同位素地球化学研究及其对矿床成因的制约  

Fluid inclusion and stable isotope constraints on the genesis of the Mazhuangshan gold deposit, eastern Tianshan Mountains of China

作　　者：李新俊[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研究重点实验室,北京100101

出　　处：《岩石学报》2002年第4期551-558,共8页Acta Petrologica Sinica

基　　金：国家重点基础研究发展规划项目 (编号 2 0 0 1 CB4 0 980 3;G1 9990 4 32 0 4 )资助

摘　　要：在详细的矿床地质研究基础上 ,对马庄山金矿床流体包裹体和氢、氧、硫、铅同位素组成进行了研究。成矿流体具有中温、中低盐度、富 H2 O、CO2 和富 Na+ 、K+ 、Cl- 离子等特征。氢、氧、硫同位素组成表明 ,成矿流体存在着两个主要来源 :岩浆流体和大气降水来源的加热地下水。铅同位素组成分布区间较为宽广且构成良好的线性相关 (R2≥ 0 .98) ,反映金属物质的多源性以及地壳和地幔各个储库的混合趋势。显微温度计及气体组分间的协变关系的不一致性 ,排除了去气作用存在的可能性。流体包裹体和同位素综合研究表明 ,两种来源流体发生了混合作用 。On the basis of investigation of ore deposit geology, petrography and microthermometry, this study performed analyses of H- and O-isotope compositions and gas compositions of sulfide- and quartz-hosted fluid inclusions, and S- and Pb-isotope compositions of sulfide separates from the Mazhuangshan gold deposit, eastern Tianshan Mountains of China. The ore-forming fluid is characterized by medium temperature, medium to low salinities, and is rich in CO2 and Na+, K+, Cl- ions. Compared with gangue quartz-hosted fluid inclusions, the sulfide-hosted ones are richer in gaseous species CO2, CO, H2S and O-2 etc. Most other gaseous components, except for CO2, do not exhibit linear correlations with H2O. The deltaD and delta(18)O values of inclusion water from quartz vary from -93parts per thousand to -106parts per thousand, and from 1.1parts per thousand to 2.4parts per thousand, respectively. Pyrite delta(34)S values are centered around 4.5similar to6.5parts per thousand. Integrated isotopic data point to two major contributions to the mineralizing fluid that include the magmatic fluid and the meteoric-derived groundwater. The Pb-206/Pb-204, Pb-207/Pb-204, and Pb-208/Pb-204 values of pyrite range from 17.896 to 18.449, from 15.256 to 15.7609 and from 37.076 to 38.711, respectively. They show good linear correlations, with correlation coefficients greater than 0.98. These characteristics indicate multi-sources for the metallic materials that range from the crust to the mantle. In summary, fluid mixing is the main mechanism for the formation of the Mazhuanshan gold deposit. The magmatic fluid was released from the magma intrusion mix with meteoric-derived groundwater to generate the ore-forming fluid. The ore-forming. fluid circulates crustal rocks and extract metallogenetic materials therein.

关 键 词：地球化学 流体包裹体 同位素 流体混合作用 金矿床 成因 去气作用 

分 类 号：P618.13[天文地球—矿床学] P597[天文地球—地质学]