新疆西天山达巴特斑岩铜钼矿床成矿流体演化  

The Evolution of Ore-Forming Fluid of the Dabate Porphyry Cu-Mo Deposit in Western Tianshan,Xinjiang,China

作　　者：刘畅[1] 薛春纪[1] 赵晓波[1] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,地球科学与资源学院,北京100083

出　　处：《地质与勘探》2016年第5期799-814,共16页Geology and Exploration

基　　金：国家自然科学基金(U1303292);国家科技支撑计划(2011BAB06B02);中国地质调查局工作项目(1212011085069)共同资助

摘　　要：新疆达巴特铜钼矿床位于天山造山带的北缘,赛里木地块的中部,成矿与晚石炭世-早二叠世浅成侵入体有关。对该矿床详细的矿石组构、流体包裹体显微测温和激光拉曼光谱分析揭示,其流体成矿先后经历了辉钼矿-黄铜矿-石英脉（Ⅰ）、无矿石英脉（Ⅱ）、辉钼矿-石英脉（Ⅲ）和方解石-石英脉（Ⅳ）等4个阶段。从早到晚不同阶段,包裹体均一温度集中分布在336-414℃、276-393℃、221-396℃、192-287℃,盐度为（4.5-9.9）%Na Cleq、（1.6-8.4）%Na Cleq、（1.2-45.6）%Na Cleq、（1.6-7.5）%Na Cleq,密度为0.57-0.76 g/cm^3、0.54-0.80 g/cm^3、0.51-1.11 g/cm^3、0.76-0.91 g/cm^3,随成矿流体温度、盐度降低,密度渐升,还原性增强。Ⅰ、Ⅲ阶段都发育矿化,包裹体具有明显的沸腾特征,且气相成分中均发现CO2,表明Ⅰ和Ⅲ阶段的流体沸腾可能导致金属沉淀,且CO2对金属运移可能具有重要作用。压力估算得到达巴特矿床Ⅰ、Ⅱ、Ⅲ、Ⅳ阶段脉体的成矿深度分别为0.5-1.1 km、0.3-1.0 km、0.5-1.0km、0.4-1.0km。矿体矿石、围岩蚀变和流体包裹体具有斑岩型矿床的特点。结合前人资料,认为达巴特为一典型斑岩型矿床。The Dabate Cu- Mo deposit is located in the middle of the Sailimu block,Northern Tianshan Orogenic. Its mineralizations relate with the hypabyssal intrusive rocks which were fromed during the Late Carboniferous and Early Permian. Through detailed observation of ore fabric,microthermometry of fluid inclusions and laser Raman spectra of fluid inclusions in this deposit,it reveals that its fluid mineralizing has gone through 4 stages of molybdenite- chalcopyrite- quartz vein（ Ⅰ）,barren quartz vein（ Ⅱ）,molybdenite- quartz vein（ Ⅲ） and calcite- quartz vein（ Ⅳ）. From early stage to late stage,the inclusions have homogenization temperatures ranging from 336 - 414℃,276 - 393℃,221 - 396℃ and 192 - 287℃,salinities ranging from（ 4. 5 - 9. 9） % NaC leq,（ 1. 6 - 8. 4） % NaC leq,（ 1. 2 - 45. 6） % NaC leq and（ 1. 6 - 7. 5） % NaC leq and densities ranging from 0. 57 - 0. 76 g/cm^3,0. 54 - 0. 80 g / cm^3,0. 51 - 1. 11 g/cm^3,0. 76 - 0. 91 g/cm^3. Their temperatures and salinities are gradually lower,their densities are gradually higher,and their reducibility is gradually stronger. The Ⅰ stage and Ⅲ stage both have the mineralization,and they both have the characteristic of fluid boiling;CO2is found in vapor phase atⅠstage and Ⅲ stage,and this phenomenon can indicate that the fluid boiling can result in the precipitation of metal elements and CO2 has a significant effect on the metal- transport at these two stage. The pressure estimation in the Dabate deposit shows that the depth is 0. 5 -1. 1km,0. 3 - 1. 0km,0. 5 - 1. 0km and 0. 4 - 1. 0km from early stage to the late stage. The orebodies,ores,wall rock alterations and fluid inclusions have the characteristics of porphyry deposits. On the basic of the former date,the Dabate Cu- Mo deposit is inferred to be a typical porphyry- type deposit.

关 键 词：流体包裹体 成矿流体演化 斑岩矿床 达巴特铜钼矿 西天山 

分 类 号：P618.41[天文地球—矿床学] P618.65[天文地球—地质学]