塔吾尔别克-阿庇因迪斑岩型金矿特征

THE CHARACTERISTICS OF TAWUERBIEKE-ABIYINDI PORPHYRYTYPE OF GOLD DEPOSIT

矿床的形成与矿区二长斑岩岩体有关 .岩体内发育 4组原生节理或裂隙带 ,这些节理或裂隙带控制了矿体的分布 ,特别是它们的交汇部位是成矿的良好部位 .矿体形态为脉状、网脉状和透镜体状 .有 4种矿石类型 :黄铁矿石英脉型 ;黄铁矿硅酸盐石英脉型 ;黄铁绢英岩型和细脉浸染型 .矿床可以划分为 2个成矿期 :内生成矿期和表生成矿期 .内生成矿期划分 3个成矿阶段 ,第 2成矿阶段是金矿主成矿阶段 .矿物组合为黄铁矿、自然金、银金矿、石英、绿泥石、方解石、白云石、绢云母、白云母和重晶石 .矿体的围岩蚀变主要为硅化、绢云母化、黄铁绢英岩化、绿泥石化、硅酸盐化 .氢氧同位素、硫同位素以及流体包裹体的研究表明 ,成矿热液为岩浆热液和大气降水的混合体 .成矿热液温度为130℃ ,成矿压力为 2 2MPa ,盐度 1 0 3%,氧逸度 -36 7～ -38 8,pH =5 8～ 8 8.成矿流体早期显酸性 ,晚期显碱性 .认为该矿床为浅成低温、低盐度流体成矿 ,属于次火山斑岩型金矿 .

Tawuerbieke-Abiyindi gold field, located in Upper Palaeozoic Tulasu volcanic fault basin, two kilometers to the south of Axi gold deposit, belongs to Yili-Middle Tianshan continental crust plate block of Khazakstan plate. In the ore field, there occurred a monzonite porphyry rock body, within which four groups of primary joints and fissures are developed. The fissures make up a number of belts which control ore bodies. The ore bodies are in single vein, network and lens form. There are four types of ore, i.e., pyrite quartz vein, pyrite carbonate quartz vein, pyrite sericite-quartzite and veinlet-disseminated types. The mineralization can be divided into endogenetic and supergenetic epoches. The former can be subdivided into three metallogenic stages and the second stage is the major one for gold deposition. The mineral association consists of pyrite, native gold, electrum, quartz, chlorite, calcite, dolomite, sericite, muscovite and barite. The wall rock alteration include silicification, sericitization. chloritization and carbonation. The study on H, O and S isotopes and fluid inclusion of quartz vein indicates that the ore-forming fluid is derived from the mixture of magmatic hydrothermal and meteoric water. The mineralization occurred at temperature of 130℃, pressure of 22 MPa, salinity of 1.03%, pHs of 5.8 to 8.8 and oxygen fugacities of -36.7 to -38.8. Form early to late stages, the nature of ore-forming fluid ranged from acidic to alkaline. Based on the above, it is recognized as subvolcanic porphyry gold deposit.