摘要
新疆哈密红海-黄土坡VMS矿床位于东天山卡拉塔格隆起带,是卡拉塔格矿集区内新发现的块状硫化物矿床。矿体产于卡拉塔格隆起带核部火山-沉积岩建造中,具有典型的VMS型矿床"上层下脉"二元结构特征。该矿床中含金硫化物矿石主要有块状黄铁矿-黄铜矿、块状黄铁矿-黄铜矿-闪锌矿、块状黄铁矿-闪锌矿-黄铜矿和块状闪锌矿。文中在对各类含金硫化物矿石进行详细的矿相学研究基础上,结合扫描电子显微镜与能谱仪联用技术(SEM/EDS),对硫化物样品中金、银的赋存状态进行研究。结果表明,4种块状硫化物中的主要矿物形成于多个期次,主要包括VMS成矿期(黄铁矿阶段、闪锌矿-黄铜矿-黝铜矿-方铅矿阶段、石英-重晶石阶段)、热液叠加期(石英-黄铁矿-黄铜矿-闪锌矿-方铅矿阶段)和表生期(铜蓝-纤铁矿阶段)。矿区首次发现4颗金银金属互化物(银金矿、碲银矿),其较大的化学成分差异指示了热液环境由中酸性-中性转变为更有利于Au、Ag迁移沉淀的偏碱性。后期的偏碱性热液对VMS成矿期形成矿物产生了交代作用,使得Au、Ag活化再富集。由于后期热液叠加改造,红海VMS型矿床中Au、Ag不仅赋存于VMS成矿期后期中低温闪锌矿-黄铜矿阶段,也赋存于VMS成矿期早期中高温黄铁矿阶段,并贯穿整个热液叠加期。各含金矿物组合中除4颗金银金属互化物外Au多呈显微不可见状态,推测Au、Ag主要以原子或离子形式赋存于矿物晶格中或矿物空位处。
The Kalatag region in eastern Tianshan,NW China contains a number of economically important Cu deposits,including the Honghai-Huangtupo VMS-type Cu-Zn deposit hosted in the volcanic-sedimentary rocks of the Late Ordovician to Early Silurian Daliugou Formation.The characteristic dualistic structure of the CuZn deposit features concordant massive sulfide and discordant vein-type ores in the footwall strata.The massive auriferous sulfide ores consist of pyrite-chalcopyrite,pyrite-chalcopyrite-sphalerite,pyrite-sphaleritechalcopyrite and sphalerite.Based on detailed mineragraphic analysis of various kinds of auriferous sulfide ores,and combined with scanning electron microscope and energy dispersive spectrometer hyphenated techniques（SEM/EDS）,we clarified that the principle ore minerals are pyrite,chalcopyrite and sphalerite,while tetrahedrite,galena and pyrrhotite occur in minor quantities;gangue minerals are mainly quartz,sericite and barite with lesser chlorite,plagioclase and carbonate.Mineralization of the Honghai deposit can be divided into three periods：VMS mineralization,hydrothermal overlapping and supergene periods.The VMS mineralization period can be further subdivided into pyrite,sphalerite-chalcopyrite-tetrahedrite-galena and quartz-barite stages.Four grains of natural gold and silver metallic mineral were found in this deposit for the first time,their very different chemical contents inferred that the hydrothermal environment went through a transformation from intermediate-acid to alkalescent,which benefited Au and Ag transport.Au and Ag were activated and re-enriched through metasomatism of minerals formed in the VMS mineralization period,by the late alkalescent hydrothermal solution.Through metasomatism,Au and Ag mineralization occurred not only in the intermediate-hypothermal sphalerite-chalcopyrite stage of the late VMS mineralization period, but also in the intermediate-hyperthermal pyrite stage of the early VMS mineralization as well as the whole hydrothermal overlapping periods.In all miner
作者
李遥
邓小华
吴艳爽
岳素伟
林振文
杨利亚
陈曦
许骏
LI Yao;DENG Xiaohua;WU Yanshuang;YUE Suwei;LIN Zhenwen;YANG Liya;CHEN Xi;XU Jun(Department of Earth Sciences,University College London,London WCIE 6BT,UK Beijing Institute of Geology for Mineral Resources,Beijing 100012,China;Xinjiang Research Center for Mineral Resources,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Orumqi 830011,China;4.School of Jewelry,Guangzhou College,South China University of Technology,Guangzhou 510800,Chin;5.Guangdong Institute of Marine Geological Survey,Guangzhou 51008;6.Henan Nonferrous Metals Geological Exploration Institute,Zhengzhou 450052,China;7.Chengdu Geological Research Institute,Sichuan Metallurgical and Geological Exploration Bureau,Chengdu 610203,China)
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2018年第5期69-82,共14页
Earth Science Frontiers
基金
国家重点基础研究发展计划“973”项目(2014CB440803)
国家自然科学基金项目(41572077,41602087)
中国地质调查局项目(121201004000160901-66,DD20160071)
国土资源部公益性行业科研专项(201411026)
