东天山卡拉塔格西二区铁铜矿床地质地球化学特征及成因
Geological and Geochemical Characteristics and Genesis of Xierqu Fe-Cu Deposit in the Kalatag District, Eastern Tianshan, NW China

西二区铁铜矿床是东天山卡拉塔格地区近年来新发现的矿床，但其矿床成因类型尚不明确.通过开展系统的电子探针、流体包裹体及H、O同位素研究，结果表明矿体赋存于大南湖组火山岩-火山碎屑岩中，受断裂控制，矿体呈似层状、透镜状.矿石结构主要为粒状结构和交代结构，矿石构造以块状构造和条带状构造为主.金属矿物主要为磁铁矿，脉石矿物主要为石榴子石、绿帘石、绿泥石、方解石等.成矿过程可划分为干矽卡岩、磁铁矿、石英-硫化物、碳酸盐这4个阶段.电子探针表明矿床早期形成钙铁榴石，磁铁矿阶段形成富铁矿石和富铁绿帘石.流体包裹体研究表明，从早到晚，成矿温度和盐度逐渐降低.HO同位素表明成矿流体以岩浆水为主，演化至大气降水.由此可知西二区铁铜矿床属于矽卡岩型铁铜矿床.
Xierqu is a newly discovered FeCu deposit in the Kalatag district of the eastern Tianshan, NW China. However, the genesis of deposit remains relatively unclear. Electron probe, fluid inclusion and H, O isotopes are studied in this paper. It is found that the ore body is hosted by volcanic rocks and pyroclastic rocks of the Dananhu Formation, and controlled by NW trending faults. The ore is dominated by massive and banding structures, and is mainly of granular and metasomatic ore textures. The metallic minerals are comprised of magnetite, and the gangue minerals consist of garnet, epidote, chlorite and calcite. Based on the ore textures, structures and observed mineral assemblages, the deposit was formed in a fourstage hydrothermal process, namely dry skarn, magnetite sulfide and carbonate stages. Microthermometric data shows that the ore fluid system evolved from middlehigh temperature (304-352℃), probably magmatic hydrothermal to lower temperature (151-270℃) meteoric fluid, which is confirmed by HO isotopes. We thus propose that the Xierqu FeCu deposit may be considered as a skarn mineral system