新疆包古图Ⅲ-2号岩体锑矿化特征

Characteristics of antimony mineralization in the Baogutu intrusive body Ⅲ-2,Xinjiang Province

报道了位于西准噶尔南部包古图地区Ⅲ-2号岩体东部边界的锑矿化.研究表明:锑矿化过程可划分为3个阶段:早期自然锑阶段,产出自然锑和磁黄铁矿的共生组合;中期硫锑铁矿阶段,硫锑铁矿与磁黄铁矿、黄铁矿和毒砂共生产出;晚期辉锑矿阶段,辉锑矿大量结晶,交代早期阶段自然锑和磁黄铁矿.矿物成分和相分析表明,早期阶段氧逸度的降低是导致自然锑沉淀的主要因素,晚期阶段温度降低导致辉锑矿大量沉淀.体系的硫逸度为-8^-13,从早期到晚期阶段,硫逸度明显上升.锑矿化的发现及研究补充完善了西准噶尔地区的矿产类型,具有理论意义及实践价值.

Antimony mineralization developed in the east boundary of the intrusion Ⅲ-2 in Baogutu area in the south of the West Junggar. The mineralization process can be divided into three stages： the early native antimony stage when native antimony coexisted with pyrrhotite; the middle gudmundite stage when gudmundite coexisted with pyrrhotite, pyrite and arsenopyrite; the late stibnite stage when plenty of stibnite replaced native antimony and pyrrhotite. Mineral compositions and phase relations indicated that precipitations of native antimony were mainly controlled by the decrease of oxygen fugacity during the early stage. The decreases in temperature resulted in the precipitation of stibnite during the late stage. The sulfur fugacity of the ore-forming process was logf（S）_2 =-8--13, increasing from the early to the late stages. The study of antimony mineralization supplements the mineral types in the West Junggar and is of great theoretical and practical value.