| 胶东三山岛金矿床黄铁矿原位微区微量元素特征及对矿床成因的指示 |
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| 引用本文： | 林祖苇,赵新福,熊乐,朱照先.胶东三山岛金矿床黄铁矿原位微区微量元素特征及对矿床成因的指示[J].地球科学进展,2019(4):399-413. |
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| 作者姓名： | 林祖苇 赵新福 熊乐 朱照先 |
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| 作者单位： | 中国地质大学(武汉)资源学院 |
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| 基金项目： | 国家重点研发计划项目“华北东部巨量金来源、迁移与富集机理”(编号:2016YFC0600104)资助~~ |
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| 摘 要： | 胶东地区是我国最大金成矿聚集区,其金矿床的成因长期以来一直存在很大争议,三山岛金矿床是胶东地区最大的金矿床,通过采用LA-ICP-MS分析不同阶段黄铁矿中微量元素组成,可以探讨成矿流体演化及成矿物质来源。根据野外地质特征及岩相学观察,结合SEM结构分析将三山岛金矿床的黄铁矿分为3个阶段,6个亚类,即黄铁绢英岩化带(Py1)中包裹大量绢云母和石英的Py1-a和表面光滑的Py1-b,石英—黄铁矿±菱铁矿脉(Py2)中富含矿物包裹体的Py2-a和与菱铁矿共生且表面光滑的Py2-b,石英—多金属硫化物脉(Py3)中有很多细粒多金属硫化物包裹体的Py3-a和表面光滑的Py3-b。3个阶段黄铁矿晶格中金含量均很低,大部分小于1×10^-6,金主要以可见金形式存在。从早阶段到晚阶段黄铁矿中Au与Ag,Cu,Pb,Sb有较好的正相关性,且含量有逐渐增加的趋势。最早阶段黄铁矿中Co+Ni的含量很高(最高为9268×10^-6),反映了早期黄铁矿可能来源于岩浆岩源区,后期Co/Ni值逐渐降低,暗示了成矿流体温度逐渐降低。结合地质特征和黄铁矿微量元素研究,表明三山岛金矿床成矿物质可能来源于深部岩浆热液储库,通过地震泵机制沿断裂构造多次侵位成矿。
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| 关 键 词： | 三山岛金矿床 LA-ICP-MS 黄铁矿 微量元素 矿床成因 |
In-situ Trace Element Analysis Characteristics of Pyrite in Sanshandao Gold Deposit in Jiaodong Peninsula:Implications for Ore Genesis |
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| Lin Zuwei,Zhao Xinfu,Xiong Le,Zhu Zhaoxian.In-situ Trace Element Analysis Characteristics of Pyrite in Sanshandao Gold Deposit in Jiaodong Peninsula:Implications for Ore Genesis[J].Advance in Earth Sciences,2019(4):399-413. |
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| Authors: | Lin Zuwei Zhao Xinfu Xiong Le Zhu Zhaoxian |
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| Institution: | (Faculty of Earth Resources,China University of Geosciences,Wuhan 430074,China) |
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| Abstract: | There are controversies about the genesis of the lode gold deposits in Jiaodong area. The Sanshandao gold deposit is the largest one in Jiaodong area. To better understand the genesis of the gold deposit, it is necessary to know the evolution of ore-forming fluid and the source of ore-forming material for the Sanshandao gold deposit. In this paper,the trace element composition of pyrite at different metallogenic stages in the Sanshandao gold deposit was analyzed by using LA-ICP-MS. Based on geological characteristics and petrography observation and SEM analysis,pyrite can be divided into three stages and six classes,including porous Py1-a and smooth Py1-b in pyrite-sericite-quartz alteration(Py1),many mineral inclusions in the Py2-a and smooth Py2-b associated with carbonate in the quartz-pyrite ± siderite veins(Py2),a lot of polymetallic sulfide inclusions hosted Py3-a and Py3-b with smooth and oscillation band in the quartz-polymetallic sulfide vein(Py3). The experimental results show that the gold content is very low in the lattice of pyrite,most of which is less than 1×10^-6,and gold mainly occurs in the form of visible gold. The contents of Au,Ag,Cu,Pb and Sb of pyrite gradually increase from early stage to late stage. The high content of Co+Ni in the earliest stage (up to 9268 × 10^-6)reflects that pyrite in the early stage is likely derived from magma,and the Co / Ni ratio gradually decreases,suggesting the decrease of ore forming fluid temperature. Combined with the geological observations and trace elements component of pyrite,the study shows that the genesis of the Sanshandao gold deposit is related to the evolution of magmatic hydrothermal reservoir. The ore-forming fluid is transported several times along the fault by seismic pumping. |
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| Keywords: | Sanshandao Gold Deposit LA-ICP-MS Pyrite Trace element Ore genesis |
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