赣北大湖塘地区昆山钨-钼-铜矿床流体包裹体研究和稳定同位素特征  

Fluid inclusion study and stable isotope characteristics of the Kunshan W-Mo-Cu deposit in the Dahutang area,northern Jiangxi Province,China

作　　者：张明玉[1] 丰成友[1] 武广[1] 王辉[2] 吴玉[3] 韩梅梅[3] 武文恒 ZHANG MingYu;FENG ChengYou;WU Guang;WANG Hui;WU Yu;HAN MeiMei;WU WenHeng(MLR Key laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chiaese Academy of Geological Sciences,Beijing 100037,China;School of Earth Sciences and Resources,Chang＇an University,Xi＇an 710054,China;Institute of Geomechanics,Chinese Academy of Geologleal Sciences,Beijing 100081,China;The Faculty of Science,the University of Melbourne,Melbourne 3010,Australia)

机构地区：[1]中国地质科学院矿产资源研究所、国土资源部成矿作用与资源评价重点实验室,北京100037 [2]长安大学地球科学与资源学院,西安710054 [3]中国地质科学院地质力学研究所,北京100081 [4]The Faculty of Science, the University of Melbourne, Melbourne 3010

出　　处：《岩石学报》2018年第9期2615-2631,共17页Acta Petrologica Sinica

基　　金：国家重点研发计划课题(2016YFC0600205); 中国地质调查局高层次地质人才培养计划(201309); 青年地质英才计划(201112)联合资助

摘　　要：昆山矿床位于大湖塘钨多金属矿田的南部,产出石英细脉带型W-Mo-Cu矿体。该矿床的成矿过程可以划分为黑钨矿-石英阶段(Ⅰ)、辉钼矿-石英阶段(Ⅱ)、黄铜矿-石英阶段(Ⅲ)及石英-方解石阶段(Ⅳ)。本文通过流体包裹体岩相学、显微测温、激光拉曼光谱和稳定同位素研究,探讨了昆山矿床的成因机制。研究结果表明,昆山矿床发育纯气相型(PG)、纯液相型(PL)、富液两相水溶液型(WL)三类包裹体。Ⅰ阶段主要发育WL型流体包裹体,并有少量PG型包裹体,均一温度为236～388℃,盐度为0. 5%～13. 8%NaCleqv,密度为0. 54～0. 90g/cm^3;Ⅱ阶段亦主要发育WL型和少量PG型包裹体,其均一温度为221～390℃,盐度为0. 5%～12. 7%Na Cleqv,密度为0. 51～0. 93g/cm^3;Ⅲ阶段主要发育WL型包裹体,均一温度为228～376℃,盐度为0. 7%～11. 2%NaCleqv,密度为0. 57～0. 91g/cm^3;Ⅳ阶段主要发育WL型包裹体,并有少量的PL型包裹体,其均一温度为173～288℃,盐度为0. 4%～11. 8%NaCleqv,密度为0. 76～0. 97g/cm^3。主成矿阶段流体属于中高温、中低盐度、中等密度流体,成矿晚阶段流体属于中低温、中低盐度、中高密度流体。包裹体气相成分主要是H_2O,亦有少量CH_4和CO_2,成矿流体总体上属于H_2O-NaCl-(CH_4-CO_2)体系。Ⅰ、Ⅱ和Ⅲ阶段成矿流体的δD值为-92‰～-56‰,计算获得的δ^(18)O水值为3. 8‰～6. 4‰;石英-方解石阶段的δD值为-68‰～-58‰,δ^(18)O水值为0. 5‰～0. 7‰。H-O同位素结果表明,昆山矿床主成矿阶段的流体以岩浆水为主,成矿晚阶段有少量的大气降水加入。金属硫化物的δ^(34)S值分布集中,其值为-1. 5‰～3. 0‰,表明成矿流体中的硫主要来自深源岩浆。辉钼矿-石英阶段的石英包裹体中CO_2的δ^(13)CV-PDB值为-6. 6‰和-5. 9‰,平均-6. 3‰;晚阶段石英-方解石脉中方解石的δ^(13)CV-PDB值为-12. 3‰～-10. 2‰,平均-11. 0‰,表明昆山矿床主成矿阶段�The quartz veinlet-type Kunshan W-Mo-Cu deposit is located in the southern part of the Dahutang ore field,situated in the central area of the Jiuling tungsten-polymetallic ore cluster in northern Jiangxi Province. The ore-forming process of the deposit can be divided into four stages： wolframite-quartz stage（ Ⅰ）,molybdenite-quartz stage（ Ⅱ）,chalcopyrite-quartz stage（ Ⅲ） and quartzcalcite stage（ Ⅳ）. In this paper,based on the previous research results and field geological survey,a systematic study of fluid inclusions and H-O-C-S isotopes was conducted. Three types of fluid inclusions（ FIs） have been distinguished in various quartz veins including pure liquid（ PL）,pure gas（ PG）,liquid-rich two-phase（ WL） inclusions. The FIs in the stage I are mainly WL-type with minor PG-type,and their homogenization temperatures,salinities and densities vary from 236℃ to 388℃,0. 5% to 13. 8% Na Cleqv and 0. 54 g/cm3 to 0. 90 g/cm3,respectively. The FIs in the stage Ⅱ are also mainly WL-type with minor PG-type,and their homogenization temperatures,salinities and densities vary from 221℃ to 390℃,0. 5% to 12. 7% Na Cleqv and 0. 51 g/cm3 to 0. 93 g/cm3,respectively. The FIs of the stage Ⅲ are composed of WL-type FIs,and their homogenization temperatures,salinities and densities vary from 228℃ to 376℃,0. 7% to 11. 2% Na Cleqv and 0. 57 g/cm3 to 0. 91 g/cm3,respectively. The FIs in the stage Ⅳare mainly WL-type with minor PL-type,and their homogenization temperatures,salinities and densities vary from 173℃ to 288℃,0. 4% to 11. 8% Na Cleqv and 0. 76 g/cm3 to 0. 97 g/cm3,respectively. The main ore-forming stage（ stages Ⅰ,Ⅱ and Ⅲ） fluid is characterized by medium-high temperature,medium-low salinity and medium density,while the fluid of the stage Ⅳ is characterized by medium-low temperature,medium-low salinity and medium-high density. The gas-phase composition of the FIs is mainly H2O with minor amounts of CH4 and CO2,indicating that the ore-forming fluid of the Ku

关 键 词：流体包裹体 H-O-C-S同位素 昆山W-Mo-Cu矿床 大湖塘矿田 赣北 

分 类 号：P597.2[天文地球—地球化学]