藏南扎西康锑铅锌银矿床地质及成矿流体特征

发布时间：2018-02-23 16:41

  本文关键词： 锑铅锌银多金属矿 流体包裹体 成矿作用 扎西康　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：藏南扎西康锑铅锌银矿床由于其巨大的矿产资源潜力和复杂的矿床类型近年来受到诸多学者的关注。本论文通过扎西康矿床地质特征研究及流体包裹体分析,探讨了成矿作用及可能的矿床类型。扎西康矿床矿体主要赋存于下侏罗统日当组地层中,矿体主要受近南北向断裂控制,次为北东 南西向断裂。根据矿物的共生组合、交切关系将扎西康矿床划分为二大成矿期、六个成矿阶段,即早期似喷流-沉积期(I)和晚期岩浆热液叠加改造期(II)。似喷流-沉积期可细分为2个成矿阶段,分别为锰铁碳酸盐-闪锌矿-黄铁矿-毒砂阶段(I-1)、锰铁碳酸盐-闪锌矿-方铅矿-黄铁矿±毒砂阶段(I-2);晚期岩浆热液改造期可以划分4个成矿阶段,分别为石英(方解石)-闪锌矿-方铅矿-黄铁矿-黄铜矿阶段(II-1)、石英-硫盐阶段(II-2)、石英-辉锑矿-辰砂阶段(II-3)、石英±方解石脉阶段(II-4)。流体包裹体研究发现,矿床各成矿期次阶段的各矿物中包裹体类型比较单一,主要以富液的气液两相水溶液包裹体为主,缺少两相型CO2包裹体和三相型CO2-H2O包裹体。早期成矿流体温度峰值区间为220℃~240℃,流体盐度(wt%Na Clequiv,后同)峰值区间为12%~15%;晚期成矿流温度具有递减趋势,峰值区间分别为:230℃~310℃(II-1)、230℃~270℃(II-2)、230℃~270℃(II-3)、230℃~260℃(II-4),盐度也有弱的递减趋势,峰值区间分别为:6%~10t%(II-1)、6%~9%(II-2)、6%~9%(II-3)、3%~6%(II-4)。早期铅锌成矿流体属低温、中等盐度的H2O-Na Cl体系,与SEDEX型、MVT型矿床相似;晚期锑成矿流体属于中低温、低盐度H2O-Na Cl体系,与岩浆热液脉型矿床相似(浅部辉锑矿化属于热泉型矿化)。结合前人H-O同位素研究认为矿床至少存在两期成矿流体。综合认为扎西康锑铅锌银矿床为似喷流沉积-岩浆热液改造型矿床。
[Abstract]:The Zaxikang antimony, lead, zinc and silver deposit in southern Tibet has attracted many scholars' attention in recent years because of its huge mineral resource potential and complex deposit types. In this paper, the geological characteristics of the Zaxikang deposit and fluid inclusion analysis are studied. The ore bodies of Zaxikang deposit are mainly located in the strata of the Lower Jurassic Ridang formation, and the orebodies are mainly controlled by the NNE faults, the next faults are the NE-NW faults. According to the mineral symbiotic assemblages, the orebodies are mainly controlled by the NNE trending faults, according to the mineral symbiotic assemblages. The Zaxikang deposit can be divided into two major metallogenic periods by cross-shear relationship, six metallogenic stages, I. e., the early similar exhalation depositional stage (I) and the late magmatic hydrothermal superposition reformation period, which can be subdivided into two metallogenic stages, and the similar exhalation sedimentary period can be subdivided into two metallogenic stages. They are manganese ferromanganese carbonate, sphalerite, pyrite and arsenopyrite stage, manganese iron carbonate sphalerite galena and pyrite 卤arsenopyrite stage, and the late magmatic hydrothermal transformation stage can be divided into 4 metallogenic stages. They are quartz (calcite-sphalerite-galena-pyrite-chalcopyrite stage), quartz-sulfide stage (II-2), quartz-stibnite-cinnabar stage (II-3), quartz 卤calcite vein stage (II-4). The types of inclusions in each ore forming stage of the deposit are relatively single, and the main inclusions are liquid-rich gas-liquid two-phase aqueous solution inclusions. There is a lack of two-phase CO2 inclusions and three-phase CO2-H2O inclusions. The peak temperature range of early ore-forming fluid is 220 鈩，

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