多不杂铜矿床包裹体地球化学特征及地质意义

Geochemical characteristics and geological significance to the inclusions of the Duobuza copper deposit

多不杂铜矿床不同类型矿化的穿插关系和分布特征表明，其成矿作用具有明显的多期次、多阶段活动特点。根据野外详细观察，结合室内显微镜下矿石结构构造、矿物共生组合特征，把成矿作用分为三大期：岩浆后期、热液期、表生期，其中热液期又分为3个阶段：磁铁矿-辉钼矿阶段、黄铜矿-黄铁矿阶段、硬石膏-黄铁矿阶段。研究表明：（1）多不杂铜矿床包裹体极其发育，数量较多，主要呈负晶形，类型主要为含子矿物包裹体，大多数包裹体成群、成带分布，大小集中在5～20μm；均一温度主要集中在350～400℃；压力在47.9×10^5～184.2×10^5 Pa；盐度（w（NaCleqv））在36.6％～48.4％；密度1.076～1.107 g/m^3。（2）包裹体气相成分以H2 O和CO2为主，液相成分主要为Cl^-和Na^＋；随着成矿过程的进行，氧逸度、二氧化碳逸度和硫逸度逐步降低，pH值和Eh值逐步升高。（3）氢氧同位素组成特征表明成矿早期主要以岩浆水为主，随着成矿作用的进行，成矿温度逐渐下降，大气降水的比例逐渐增加。（4）该矿床的成矿作用主要发生在高温、高盐度、浅成、弱酸性以及强氧化环境中，成矿流体主要来源于岩浆水。

The mineralization relations and distribution characteristics in Duobuza copper deposit with different types show that in the mineralization there are multi-times and multi-stage activity characteristics. According to detailed field observation and the study of ore structure and mineral assemblages characteristics, the mineralization can be divided into three periods. They are the post magrnatic period, hydrothermal period and supergene stage. The second period consists of magnetite-molybdenite stage, chalcopyritepyrite stage and the anhydritepyrite stage. It is shown that （ 1 ） The Duobuza copper deposit inclusions are extremely developed and in larger quantities. Most of them （ in the 5 - 20 ×m size） mainly are daughter mineral inclusions and shaped in a negative crystal, existing in groups or in strips. Besides, homogenization temperatures are between 350 and 400 ℃, while pressure ranges from 47.9 × 10^5 to 184. 2 × 10^5 Pa. The salinity focuses between 36. 6% -48.4% NaC1. eqv and density varies from 1. 076 to 1. 107 g/m^3. （2） Inclusions in the gas phase primarily are made up of H2O and CO2. Nevertheless, liquid phase composes mainly of Cl^- and Na ^＋. In the mineralization process, oxygen fugacity, carbon dioxide fugacity, and sulfur fugacity are gradually reduced. On the contrary, Ph and Eh values gradually increased in this process. （3） Hydrogen and oxygen isotope composition indicates that the early mineralization contained largely magmatic water. However, along with the mineralization, the mineralization temperature gradually decreased and there appeared a heavier proportion of meteoric water. （4） The Duobuza copper deposit mineralization occurs mainly in those environments： high temperature and high salinity conditions, shallow depth, weak acid and strong oxidizing cases. The ore forming fluids mainly derived from magmatic water.