投稿时间：2023-05-19
修订日期：2023-11-16
网络发布日期：2023-12-29
中文摘要:照壁山金铅锌多金属矿床位于东天山博格达岛弧带中部，是近年来新发现的矿床。矿体赋存于柳树沟组第三岩性段火山岩-火山碎屑岩中，以脉状、浸染状矿化为主，发育硅化、明矾石化蚀变，其成矿过程可分为3个阶段：①石英-黄铁矿-毒砂阶段（Ⅰ）；②石英-金-黄铁矿-闪锌矿-方铅矿阶段（Ⅱ）；③石英-黄铁矿-黄铜矿阶段（Ⅲ）。赋矿围岩为双峰式火山岩组合，玄武岩高Mg（Mg#=36.25%~58.77%）、富钠贫钾（w (Na2O/K2O)=1.95~27.35），铝饱和指数（A/CNK）在1.25~1.69之间，属过铝质拉斑玄武岩系列，较高的La/Nb（2.49~3.83）、Ba/Nb（41.00~315.38）、Ba/La（14.50~92.45）比值，反映了玄武质岩浆受到了一定的地壳物质混染，Rb、Ba、K等元素相对富集，Th、Nb、Ta等元素相对亏损，具有板内玄武岩的特征；流纹岩具有较高的全碱含量（w (Na2O+K2O)=9.50~12.45），属钾玄岩系列，轻微富集轻稀土，富集Rb、U、K等元素，亏损Nb、Ta、Sr、Ti等元素，反映了流纹岩来源于地壳物质的部分熔融；石英脉中的流体包裹体主要为气液两相，均一温度为194.2~253.5℃（Ⅱ）、156.7~201.6℃（Ⅲ），盐度为7.9%~13.2%（Ⅱ）、7.3%~12.4%（Ⅲ），成矿流体表现为中温、中低盐度、低氧逸度、低pH值特征；δDv-SMOW变化范围为-115.7‰~-95.4‰，δOv-SMOW变化范围为-0.51‰~7.19‰，表明成矿流体为岩浆热液与大气降水的混合热液。结合系统的地质、地球化学对比，文章推测照壁山金铅锌多金属矿床为中硫型浅成低温热液矿床。
Abstract:The Zhaobishan Au-Pb-Zn polymetallic deposit is a new discovery in the middle segment of the Bogda island arc in Eastern Tianshan. The deposit is hosted by the volcanic-pyroclastic rocks of the third lithologic member of the Liushugou Formation, with the major type as veinlet and disseminated mineralization, silicification and alum alteration. The ore-forming process can be divided into three stages: ① quartz-pyrite-arsenopyrite stage(Ⅰ); ② quartz-gold-pyrite-sphalerite-galena stage(Ⅱ); ③ quartz-pyrite-chalcopyrite stage(Ⅲ). The host rock is bimodal volcanic rock. The basalts have high values of Mg (Mg#=36.25%~58.77%), Na2O/K2O (1.95~27.35), A/CNK (1.25~1.69), belonging to the peraluminous tholite series. The high La/Nb (2.49~3.83), Ba/Nb (41.00~315.38), Ba/La (14.50~92.45) ratios indicate that the basalts have experienced a certain degree of crustal contamination. These rocks are enriched in Rb, Ba, K and depleted in Th, Nb, Ta, which are comparable with the geochemical features of intraplate basalts. The rhyolites of bimodal volcanic rocks exhibit high ALK (w(Na2O+K2O)=9.50~ 12.45), belonging to the potassium basalt series. They are slightly enriched in rare LERR, Rb, U, K and depleted in Nb, Ta, Sr, Ti, which indicate that the rhyolites have been derived from partial melting of crustal materials. The primary fluid inclusions trapped in quartz are mainly composed of gas and liquid. Homogenization temperatures is 194.2~253.5℃(Ⅱ), and 156.7~201.6℃(Ⅲ). Salinity is 7.9%~13.2%(Ⅱ), 7.3%~12.4%(Ⅲ), respectively. The δDv-SMOW values of fluid inclusion hosted by quartz vary from -115.7‰ to -95.4‰, and δOv-SMOW values of oreforming fluid using homogenization temperature method vary from -0.51‰ to 7.19‰, indicating that the oreforming fluid is a mixture of magmatic water and meteoric water. Combined with systematic geological and geochemical comparison, it is concluded that the Zhaobihsan Au-Pb-Zn polymetallic deposit may belong to intermediate-sulfidation epithermal deposit.
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基金项目:本文得到新疆维吾尔自治区人力资源和社会保障厅“天池英才”项目、地质过程与矿产资源国家重点实验室开放课题编号（编号：GPMR202307）、长安大学中央高校基本科研业务费专项资金（编号：300102263505）、企事业单位委托科技项目（编号：3-4-2021-266）联合资助
引用文本：
张雪琴,徐登峰,赵云,薛春纪,刘一浩,李旭广,陈波,游延祥.2023.新疆东天山照壁山金铅锌多金属矿床地质特征及矿床成因[J].矿床地质,42(6):1121~1138ZHANG XueQin,XU DengFeng,ZHAO Yun,XUE ChunJi,LIU YiHao,LI XuGuang,CHEN Bo,YOU YanXiang.2023.Geological characteristics and ore genesis of Zhaobishan Au-Pb-Zn polymetallic deposit in eastern Tianshan, Xinjiang[J].Mineral Deposits42(6):1121~1138
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