哈萨克斯坦萨亚克大型铜矿田矿物学特征及其地质意义  

Mineral characteristics of Sayak large-scale Cu ore-field in Kazakhstan and their geological significance

作　　者：李晶[1,2] 许英霞[1] 申萍[2] 潘鸿迪[3] 钟世华[2,4] Eleonora Seitmuratova 

机构地区：[1]河北联合大学,河北唐山063000 [2]中国科学院地质与地球物理研究所,北京100029 [3]长安大学地质科学与资源学院,西安710054 [4]中国科学院大学,北京100049 [5]沙特巴耶夫地质研究所地层实验室,阿拉木图050010

出　　处：《地质科学》2015年第3期850-878,共29页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金项目（编号：U1303293,41390442,41272109）、中国科学院重点部署项目（编号：KJZD-EW-TZ-G07）、国际科技交流与合作专项（编号：2010DFB23390）和国家“305”项目（编号：2011BAB06801）资助.

摘　　要：哈萨克斯坦萨亚克大型铜矿田中，矽卡岩型矿床的矿体赋存于石炭系灰岩与花岗岩类的接触带上，矿体及其周围发育大量矽卡岩。矽卡岩矿物主要由石榴子石、辉石、绿帘石、绿泥石等组成，矿石矿物主要发育黄铜矿、斑铜矿、黄铁矿、磁黄铁矿、辉钴矿等。萨亚克矽卡岩型矿床成矿作用分为5个阶段：透辉石-石榴子石矽卡岩阶段、石榴子石矽卡岩阶段、绿帘石-磁铁矿阶段、石英-硫化物阶段和碳酸盐阶段。电子探针分析结果表明，矿区矽卡岩属典型的钙质矽卡岩。其中石榴子石发育3种类型，均属钙铝-钙铁榴石固溶体系列，白早期透辉石-石榴子石矽卡岩阶段至晚期石榴子石矽卡岩阶段，由钙铁榴石向钙铝-钙铁榴石转变，并且钙铁-钙铝榴石与矿化关系最为密切。其中具环带结构的石榴子石中钙铁与钙铝含量随环带呈韵律性变化，表明生长过程中成分具震荡性变化，形成于不完全封闭的平衡条件，指示流体的多期次多阶段性；辉石以透辉石为主；绿帘石属绿帘石族中绿帘石范畴；磁铁矿TFeO含量高，与其他氧化物成分呈负相关关系。石英硫化物阶段早期发育黄铜矿一黄铁矿一磁黄铁矿一白铁矿、黄铜矿一辉钴矿矿物组合；晚期为主要矿化阶段，发育大量致密块状黄铜矿。黄铜矿显示贫硫富铜、铁特征；黄铁矿为亏硫型；磁黄铁矿属贫钻富镍型。矽卡岩矿物共生组合及石榴子石成分演化等矿物学特征显示，成矿过程中随着温度及氧逸度的降低。成矿热液由弱碱性向酸性演化，伴随热液在接触带的中和作用，以黄铜矿为主的金属硫化物富集沉淀。The ore body of skarn type deposit in Sayak is located in the contact zone between Carboniferous limestone and granite, surrounded by skarn. The skarn minerals in Sayak mainly include garnet, pyroxene, epidote and chlorite. Metallic minerals are mainly chalcopyrite, bornite, pyrite, pyrrhotite, cobaltite. The mineralization of Sayak deposit can be divided into five metallogenic stages： Diopside-garnet skarn stage, garnet skarn stage, epidote-magnetite stage, quartz-sulfide stage and carbonate stage. Electron microprobe analyses show that skarns in Sayak belong to typical calcic skarns. There are three types of garnet in skarn, and they all belong to andradite-grossularite solid solution series. The garnet shifted from andradite towards andradite-grossularite with time, and the andradite-grossularite is most relevant to the mineralization besides. The content is changing with the zone rhythmically, which means that its growth is discontinuity indicating multi-stages of fluid. The pyroxenes are mainly composed by diopside with a small amount of hedenbergite. The epidote is almost epidote with a little clinozoisite. The magnetite is composed by a high TFeO content with a negative correlation with other oxide. Chalcopyrite-pyrite-pyrrhotite-marcasite and chalcopyrite-cobahite are developed in early quartz-sulfide stage, while compact massive chalcopyrite formed in the later main stages. The chalcopyrite and pyrite are both lean sulfur and rich metallic element, and pyrrhotite is lean cobalt but rich nickel. The mineralogical features such as paragenetic association of skarn minerals and the composition evolution of garnet indicated that the ore-forming hydrothermal evolved from. alkalescence to acidity as the decrease in temperature and oxygen fugacity. Meanwhile the chalcopyrite-based metal sulfides occurred enrichment and precipitation with the neutralization in the contact zone.

关 键 词：石榴子石 矽卡岩 成因矿物学 萨亚克 哈萨克斯坦 

分 类 号：P588.3[天文地球—岩石学] P618.41[天文地球—地质学]