大兴安岭中段闹牛山浅成热液铜多金属矿床流体包裹体研究  

STUDY OF FLUID INCLUSION OF NAONIUSHAN EPITHERMAL Cu-POLYMETALLIC DEPOSIT IN THE CENTRAL GREAT XING′AN RANGE

作　　者：古阿雷 孙景贵[2] 白令安[3] 赵克强[4] 王忠禹 李俊建 付超[1] GU Alei;SUN Jinggui;BAI Lingan;ZHAO Keqiang;WANG Zhongyu;LI Junjian;FU Chao(Tianjin Center of Geological Survey,China Geological Survey（CGS）,Tianjin 300170,China;College of Earth Science,Jilin University,Changchun 130061,China;Guilin University of Technology,Guilin 541004,China;Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang 065000,China;Ningzia Geological Survey,Yinchuan 750021,China)

机构地区：[1]天津地质调查中心,天津300170 [2]吉林大学地球科学学院,吉林长春130061 [3]桂林理工大学地球科学学院,广西桂林541004 [4]中国地质科学院地球物理地球化学勘察研究所,河北廊坊065000 [5]宁夏回族自治区地质调查院,宁夏银川750021

出　　处：《矿物岩石》2018年第3期28-39,共12页Mineralogy and Petrology

基　　金：国家自然科学基金项目(41390444;41172072;41202042);中国地质调查项目(DD20160112)

摘　　要：闹牛山浅成热液铜多金属矿床是大兴安岭中部浅成热液-斑岩铜多金属矿集区内重要的矿床之一,矿床产于早白垩统玛尼吐组陆相酸性火山岩中;矿体呈脉状、网脉状、角砾状产出,受断裂控制;金属硫化物主要为黄铜矿、黄铁矿、磁黄铁矿、毒砂等。热液成矿过程可划分为4个阶段:(Ⅰ)石英-黄铁矿-辉钼矿-毒砂阶段,(Ⅱ)石英-黄铁矿-磁黄铁矿-黄铜矿阶段,(Ⅲ)石英-闪锌矿-方铅矿-黄铜矿阶段和(Ⅳ)石英-碳酸盐阶段。实验数据表明:流体包裹体的类型可分为纯气相包裹体(V型)、纯液相包裹体(L型)、气液两相盐水溶液包裹体(W型)和含子矿物的三相包裹体(S型),其中以W型居多。从早到晚矿化阶段流体发生了一系列连续变化,均一温度分别为405℃~260℃,407℃~183℃,368℃~170℃和183℃~109℃,盐度w(NaCleq)依次为3.05%~43.83%,0.35%~46.56%,0.35%~8.67%和0.71%~3.69%。激光拉曼光谱分析表明成矿流体属于H_2O-NaClCO_2±CH_4±(Mg/Ca)CO_3体系。氢-氧同位素分析结果显示,大兴安岭中段浅成热液铜矿床的初始含矿流体为残余岩浆水,成矿过程中,大气降水逐渐混入,成矿晚期演化为大气降水。综合分析认为闹牛山浅成热液铜多金属矿床成矿的主要机制是流体沸腾和混合作用,流体混合作用在主成矿期及成矿中晚期发挥着更重要的作用。Ore bodies in the Naoniushan epithermal Cu-polymetallic deposit,central Great Xing＇ an Range,are hosted in lower Cretaceous Manitu Formation acidic volcanic rocks, occurred in the forms of veins,net veins and breccias,and controlled by faults. Metal sulphide minerals in the ore are composed of chalcopyrite, pyrite, pyrrhotite, arsenopyrite and so on. The main successive mineralization stages are as follows ： （ Ⅰ ） Quartz-pyrite-molybdenite-arsenopyrite stage, （ Ⅱ ） Quartzpyrite-pyrrhotite-ehalcopyrite stage, （Ⅲ ） Quartz-galena-sphalerite-chalcopyrite stage, and （ Ⅳ ） Quartz-carbonate stage. Four types of fluid inclusions are identified as pure gas inclusions （Ⅴ- type）, pure liquid inclusions （L-type）, gas-liquid two-phase inclusions （W-type, as the main FIs）, and daughter-mineral-bearing polyphase inclusions （S-type）. The fluid experienced regular evolution from the early to late stage. It reveals that the homogenization temperatures of different stages are 405 ℃～260 ℃,407 ℃～183 ℃,368 ℃～170 ℃ ,and 183 ℃～109 ℃ ,respectively;and the salinities are 3.05%～43.83%, 0.35%～46.56%, 0.35% ～8.67%,and 0.71%～ 3.69%, re- spectively. Laser Raman analysis shows that the ore forming fluids belong to the H2O-NaCl-CO2 ± CH4±（Mg/Ca）CO3 system. Character of H-O isotopes indicate that initial ore-forming fluid is mainly derived from the residual magma, then mixed with meteoric water during mineralization, and finally transfer to meteoric water. It is considered that the mineralization mechanism is the combination of liquid boiling and mixing action,and the mixing action plays an important role in the major mineralization stage as well as in the mid-late mineralization stage.

关 键 词：流体包裹体 H-O同位素 流体演化 闹牛山铜多金属矿床 大兴安岭中段 

分 类 号：P611.1[天文地球—矿床学]