投稿时间：2022-01-04
修订日期：2022-03-29
网络发布日期：2022-07-07
中文摘要:甘肃敦煌小独山西石英脉型钨矿床位于北山成矿带柳园-俞井子裂谷带西段，经过详查和勘探工作，发现其资源量已达大型钨矿床规模。文章在野外详细观测和系统采样的基础上，对不同成矿阶段的样品使用岩相学、激光拉曼光谱、显微测温和碳、氢-氧同位素测试等方法，对矿脉中流体包裹体进行了综合研究。结果显示，该矿床矿脉中主要发育有气-液两相（Ⅰ型）和含液相CO2三相（Ⅱ型） 2类包裹体。其中，Ⅰ阶段流体呈中高温、中盐度特征，主成矿（Ⅱ）阶段呈中高温、中低盐度特征，Ⅲ阶段呈低温，低盐度特征，均一温度与盐度呈现出正相关关系。包裹体的δD和δ18O值范围分别为-98.3‰~-76.4‰和0.8‰~5.4‰，呈岩浆水与大气降水相混合的特征；方解石中流体的δ13C值为-0.26‰~-0.73‰，δ18O值为-1.26‰~-3.73‰，显示C可能来源于海相碳酸盐岩，在后期演化过程中与大气降水发生了氧同位素交换作用。成矿早期与主成矿期均受到了大气降水的影响，该矿床发生了明显的流体混合作用是该地区成矿的主要因素。
Abstract:The Xiaodushan quartz vein type tungsten deposit in Dunhuang, Gansu province, is located in the western section of the Liuyuan-Shujingzi rift zone of the Beishan metallogenic belt. After detailed investigation and exploration, the resource of the deposit has reached the scale of a large tungsten deposit. On the basis of field observation and systematic sampling, the fluid inclusions in veins of different ore-forming stages have been comprehensively studied by means of petrographic analysis, Laser Raman spectroscopy, microthermometry, and hydrogen, carbon and oxygen isotopes analysis. The results show that there are two types of inclusions in quartz veins:gas-liquid two-phase (type Ⅰ) and CO2 liquid-phase bearing three-phase (type Ⅱ). In stage Ⅰ, the fluid is characterized by medium-high temperature and medium salinity; in main stage (stage Ⅱ), the fluid is characterized by medium-high temperature and medium-low salinity; in stage Ⅲ, the fluid is characterized by low temperature and low salinity, and the homogenization temperature is positively correlated with salinity. The δD and δ18O values of the inclusions in quartz range from -98.3‰ to -76.4‰ and from 0.8‰ to 5.4‰, respectively, indicating a mixture of magmatic water and meteoric water. The δ13C and δ18O values of the calcite fluid range from -0.26‰ to -0.73‰ and -1.26‰ to -3.73‰, indicating that the carbon was probably derived from Marine carbonate rocks and had oxygen isotope exchange with meteoric precipitation during the late evolution. Both the early and main ore-forming stages were affected by meteoric precipitation, and the obvious fluid mixing occurred in the deposit, which was the main factor of mineralization in this area.
keywords:geochemistry ore-forming fluid hydrogen and oxygen isotopes carbon and oxygen isotopes fluid mixing the Xiaodushanxi tungsten deposit
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基金项目:本文得到小独山西钨金矿地质找矿综合研究项目和中国地质科学院中国矿产地质与成矿规律综合集成和服务（编号：DD20160346）子课题“南岭成矿带西段成矿规律总结项目”联合资助
引用文本：
张鸣远,刘战庆,崔丰智,李瑞霜,席昊,陈玉峰,陶超群,岑炬标.2022.甘肃敦煌小独山西钨矿床成矿流体特征及来源分析[J].矿床地质,41(3):611~622ZHANG MingYuan,LIU ZhanQing,CUI FengZhi,LI RuiShuang,XI Hao,CHEN YuFeng,TAO ChaoQun,CEN JuBiao.2022.Origin and characteristics of ore-forming fluids in Xiaodushanxi tungsten deposit, Dunhuang, Gansu[J].Mineral Deposits41(3):611~622
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