冈底斯岩浆带雄村矿床多期次成矿探讨  

The multi-stage metallogenic exploration of the Xiongcun copper-gold deposit in the magmatic zone of gangdisi in Gangdise magma zones

作　　者：张金树[1] 多吉 钟康惠[2] 赵俊兴[3] 杨成业[1] 尊珠 ZHANG Jin-shu;Dorje;ZHONG Kang-hui;ZHAO Jun-xing;YANG Cheng-ye;Tsundoe(School of Engineering,Tibet University,Lhasa 850000,China;Chengdu University of Technology,Chengdu 610059,China;Institute of Geology and Geophysics,CAS,Beijing 100029,China;The Sixth Geological Team of Tibet Geological and Mineral Exploration and Development Bureau,Lhasa 850000,China)

机构地区：[1]西藏大学工学院,西藏拉萨850000 [2]成都理工大学,四川成都610059 [3]中国科学院地质与地球物理研究所,北京100029 [4]西藏地质矿产勘查开发局第六地质大队,西藏拉萨850000

出　　处：《高原科学研究》2018年第2期1-11,共11页Plateau Science Research

基　　金：国家自然科学基金项目(41762011)

摘　　要：文章根据多次叠加成矿的矿相学证据、稀土地球化学证据、同位素地球化学证据、年代学证据,对西藏冈底斯岩浆带雄村矿床多期次成矿进行了探讨。认为雄村铜金矿代表了雅江洋俯冲阶段形成的斑岩型铜金矿,但后期存在多期叠加成矿作用。雄村铜金矿的矿石具有异常复杂的金属矿物组合(发现闪锌矿可与14种金属矿物组合,黄铜矿可与16种金属矿物组合)特征,同时具有同种矿物多种产出状态、同种矿物不同标型、同种标型组合复杂等特点;单矿物稀土地球化学表明,4个世代的石英稀土总量(∑REE=0.596706~5.423752(×10^(-6)))大于磁黄铁矿和黄铁矿的稀土总量(∑REE=0.126854~0.883578(×10^(-6))),早世代到晚世代的石英稀土总量有增加趋势,轻稀土富集程度有减弱趋势,重稀土亏损程度有递减趋势,硫化物重稀土比硅化石英重稀土偏高;雄村矿床叠加矿化的矿液来源于基性岩浆,成矿流体具有高氧逸度特点,同位素地球化学特征也具有多期次叠加成矿的特征;雄村矿床成矿背景在造山带与洋岛叠合区域,岩浆源区的形成及岩浆侵位与俯冲作用和造山作用具有一定关系,成矿金属物质源区在上地壳与地幔之间,偏地幔一侧;硫源具有岩浆硫/深源硫特征;氢氧同位素地球化学特征表明,流体以岩浆水为主,地层成分水混入较少,成矿溶液大规模活动,矿液较少混入地层水,而强度较小规模有限的前锋部位的地层水混入较多;单矿物Pb-Pb模式年龄、石英的HAESRDQ年龄显示,雄村矿床有52.7~70.4 Ma的成矿作用。According to evidence of superimposed mineralization including mineralography,REE geochemistry,Isotopic geochemistry,and chronology,multistage superposition mineralization of the Xiongcun copper-gold de-posit is studied in this paper.During the phase of oceanic crust subduction,Xiongcun copper-gold deposit stands for Porphyry copper gold formation with existing multistage superimposed mineralization later period.Based on the study of ore characteristics and genetic mineralogy,it is indicated that Xiongcun copper-gold de-posit contains complexity combination of metal mineral(sphalerite combined with 14 kinds of metal minerals,chalcopyrite with 16s),same mineral with multiple occurrence status,same mineral with different typomorphictype,and same typomorphic with complexity combination et,al,showing that it exists multi-periods,and superpo-sition mineralization.Mmonomineral REE geochemistry shows that the total content of quartz rare earth elements with four generation(ΣREE=0.596706~5.423752(×10-6))greater than that of pyrrhotite and pyrite((ΣREE=0.126854~0.883578(×10-6)).It has also shown that from early generation to late generation,total abundance of quartz REE has a growing tendency,while LREE enrichment degree has a decreasing tendency.Furthermore,HREE loss degree has decreasing tendency and HREE of sulfide is higher than that of Chloride quartz.It turns out ore-fluid superposed mineralization derived from basic magma with characteristics of high oxygen fugacity and isotope geochemical also shows character of multistage superposition metallogenic.Both mineralization back-grounds of Pb isotope show that the composite area of orogenic belt&ocean island,and magma source area&magmatic emplacement had a certain relationship with underthrusting&orogenesis;source area of ore-forming metal material is between the upper crust and mantle with slightly on the side of mantle.Source area of sulfide comes from magmas/deep source;The geochemical characteristics of oxyhydrogen isotope indicate that the fluid is dominated b

关 键 词：冈底斯 矿床 多期成矿 成矿特征 

分 类 号：P618.2[天文地球—矿床学]