大兴安岭北段偃尾山铜银矿床流体包裹体与矿床成因类型研究  

Fluid Inclusions and Genetic Type of the Yanweishan Cu-Ag Deposit in the Northern Great Xing'an Range

作　　者：韩龙[1,2] 姜迎久 

机构地区：[1]吉林大学地球科学学院,吉林长春130061 [2]黑龙江省有色金属地质勘查局706队,黑龙江齐齐哈尔161006

出　　处：《地质与勘探》2017年第3期445-455,共11页Geology and Exploration

摘　　要：偃尾山铜银矿床是大兴安岭北段呼中-塔源成矿带内新发现的中小型矿床。矿床围岩蚀变呈面状分布,主要蚀变类型为硅化、碳酸盐化、黄铁矿化、伊利石化、高岭石化和绢云母化。热液成矿期可分为三个阶段:成矿早期石英-黄铁矿阶段(含少量黄铜矿)、主成矿期石英-斑铜矿-黄铜矿-辉铜矿(含铜硫化物)阶段和成矿晚期石英-碳酸盐-萤石阶段(含少量方铅矿和闪锌矿)。该矿床流体包裹体主要为富液相包裹体,也有少量纯气相包裹体,未见含子矿物包裹体。主成矿阶段流体包裹体均一温度为155℃~342℃,峰值集中在160℃~230℃,冰点温度在﹣3.3℃~﹣0.3℃,盐度为0.53%NaC_(leqv)~5.41%Na Cleqv;流体成分以K^+、Na^+、SO_4^(2-)为主,含少量Ca^(2+)和Cl^-,气相成分以H_2O为主,含少量的CO_2;流体δ^(18)O在-11.8‰^-13.72‰之间,δD变化范围在-105‰^-137‰之间。总体上,成矿流体为低温低盐度流体,流体来源主要是大气降水,成矿流体和矿床蚀变-矿化特征显示本矿床可能为高硫型浅成低温热液矿床。流体压力的突然降低可能是成矿物质沉淀的主要机制。偃尾山矿床可能代表了区域上同时代一种新的矿床类型,后续深入研究将有助于认识该区域成矿规律和找矿方向。The Yanweishan Cu -Ag deposit is a newly discovered medium -smal｜ deposit in the Huzhong- Tayuan mineralized belt in the northern Great Xing＇ art Range. The wall rock alteration is widely distributed in this deposit and alteration minerals mainly include quartz, carbonate, pyrite, il- lite, kaolinite and sericite. Three ore mineralized stages are recognized： early quartz -pyrite stage （containing little chalcopyrite） , main quartz -bornite - chalcopyrite - chalcoeite stage and late quartz - carbonate - fluorite stage （ containing little galena and sphelarite）. The fluid inclusions include abun- dant fluid - rich two - phase inclusions and few pure - gas one - phase inclusions, without daughter mineral - bearing inclusions. The homogenization temperature of main ore - forming stage ranges from 155~C to 342~C , concentrating in 160~C to 230~C. The freezing temperature ranges from - 3.3~C to - 0. 3~ , displaying the salinity of 0.53% - 5.41% NaCleqv. The aqueous components mainly contain K^＋, Na^＋ and SO4^2- with a little Ca^2＋ and Cl^- , and a mass of H2O and a little CO2 form the gas of fluid inclusions. The δ^18O and δD of ore - forming fluid vary in - 11.8‰~ ~ - 13.72‰ and - 105‰ - - 137‰, respectively. Overall, the ore - forming fluid belongs to low temperature and low salinity fluids, which emanated from meteoric water. The characteristics of a fluid, alteration and mineralizing suggest that this deposit is of the high sulfidation epithermal type. Rapid decrease of fluid pressure may be the main mechanism of ore - forming materials precipitation. The Yanweishan deposit may represent a new type of deposits in the Huzhong - Tayuan mineralized belt and subsequent research could help understand the metallogeny and clarifying prospecting direction.

关 键 词：偃尾山铜银矿床 围岩蚀变 流体包裹体 氢氧同位素 浅成低温热液矿床 大兴安岭 

分 类 号：P618.41[天文地球—矿床学] P618.52[天文地球—地质学]