西藏尕尔穷-嘎拉勒铜金矿集区流体包裹体特征及成矿作用研究  

Characteristics of fluid inclusions and metailogenic process of Gaerqiong-Galale Cu-Au ore concentration area,Tibet

作　　者：宋俊龙[1,2] 唐菊兴[3] 张志[2] 彭智敏[2] 林鑫[4] 王艺云[1] 

机构地区：[1]成都理工大学地球科学学院,四川成都610059 [2]中国地质调查局成都地质调查中心,四川成都610081 [3]中国地质科学院矿产资源研究所,北京100037 [4]四川省地质矿产勘查开发局区域地质调查队,四川成都610213

出　　处：《矿床地质》2015年第5期999-1015,共17页Mineral Deposits

基　　金：青藏高原羌塘中部本松错复合岩基同位素地质年代学研究项目(编号:41303043);公益性行业科研专项(编号:201511017);青藏专项(编号:12120114050401);地质大调查项目(编号:12120113093700)联合资助

摘　　要：西藏革吉县尕尔穷-嘎拉勒铜金矿集区位于班公湖-怒江缝合带西段南缘。矿集区主要由矽卡岩型铜金银矿体、铁氧化物铜金矿体和斑岩型钼铜矿(化)体等组成,其中主矿体矽卡岩型铜金矿体受闪长质岩体和碳酸盐岩的控制。根据矿物组合关系,将矿集区内各类热液脉体分为早、中、晚3个阶段,中阶段为主成矿阶段。研究表明,早、中阶段石英中流体包裹体以水溶液包裹体和三相包裹体为主,其次为CO_2包裹体;晚阶段仅发育富液相的水溶液包裹体。早阶段流体包裹体的均一温度集中在403~540℃之间,盐度ω(NaCl_(eq))介于15.2%~59.3%;中阶段流体包裹体的均一温度集中在205~398℃之间,盐度ω(NaCl_(eq))介于1.9%~45.8%;晚阶段流体包裹体的均一温度集中在122~264℃之间,盐度ω(NaCl_(eq))介于3.0%~16.4%。显微激光拉曼测试结果显示,流体包裹体的气相成分以H_2O、CO_2、N_2为主,液相成分以Na^+、K^+、Ca^(2+)、Cu^(2+)、Fe^(3+)及Cl^-、HCO_3、CO_3^(2-)等为主,子矿物主要为石盐、钾盐、黄铜矿、方解石、赤铁矿等。成矿流体从早阶段到晚阶段,由高温高盐度的CO_2-H_2O-NaCl体系向中低温中低盐度的H_2O-NaCl体系演化。主成矿阶段不同类型、不同相比包裹体具有相近的均一温度,相同类型包裹体具有相近的均一温度,但是均一方式各异,显示流体不混溶或沸腾特征。流体不混溶或沸腾作用使得CO_2、H_2S等挥发分大量逃逸,导致大量硫化物沉淀,是尕尔穷-嘎拉勒铜金矿集区铜金富集成矿的原因。The Gaerqiong-Galale copper-gold ore concentration area is located in the west of the southern margin of Bangong Co - Nujiang River suture zone, Ge＇ gya County, Tibet. Two large copper-gold deposits of Gaerqiong and Galale were found, which are composed mainly of skarn type copper-gold-silver orebody, iron oxide copper- gold orebody and porphyry type molybdenum-copper orebody （mineralized body）, with the main orebody being the skarn type copper-gold orebody. The main orebody is controlled by dioritic intrusions and carbonate rock. According to mineral assemblages, the ore-forming process and veins can be divided into early, middle and late stages, with the main mineralization occurring at the middle stage. Fluid inclusions in quartz of the early and middle stage are mainly aqueous and three-phase inclusions, together with COz inclusions; whereas the late stage quartz only contains liquid-rich aqueous inclusions. Homogenization temperatures and salinities of fluid inclusions of the early stage range from 403℃ to 540℃ and 15.2% to 59.3% NaCleqv, respectivdy, whereas those of the middle stage range from 205℃ to 398Z; and w（NaCleq） 1.9% to 45.8%, respectively; the late stage liquid- rich aqueous inclusions yield homogenization temperatures of 122 -- 264℃ and salinities of w （NaCleq） 3.0 % 16.4 %. Microprobe Raman test results show that the compositions of gas phase in fluid inclusions are dominated by H2O, CO2, N2, liquid phase compositions are dominated by Na＋, K^＋, Ca^2＋, Cu^2＋, Fe^3＋ and Cl-, HCO3-, CO3^2- and daughter minerals are dominated by halite, sylvite, chalcopyrite, calcite, hematite. The evo- lution of the ore-forming fluid from the early stage to the late stage is from the high temperature and high salini- ties CO2-H2O-NaCl system to the middle-low temperature and middle-low salinity H2O-NaCl system. Different types and phase ratios of inclusions of the main mineralization stages have similar homogenization temperatures, whereas the same type inclusions have similar homog

关 键 词：地球化学 流体包裹体 铜金矿 尕尔穷-嘎拉勒 西藏 

分 类 号：P618.41[天文地球—矿床学] P618.51[天文地球—地质学]