| 山东栖霞笏山金矿床成因——元素地球化学与流体包裹体证据 |
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| 引用本文： | 智云宝,孙海瑞,李风华.山东栖霞笏山金矿床成因——元素地球化学与流体包裹体证据[J].吉林大学学报(地球科学版),2020,50(5):1552-1569. |
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| 作者姓名： | 智云宝 孙海瑞 李风华 |
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| 作者单位： | 1. 山东省地质调查院, 济南 250013;2. 中国地质调查局发展研究中心, 北京 100037;3. 自然资源部矿产勘查技术指导中心, 北京 100083 |
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| 基金项目： | 中国地质调查局项目（121201004000150017-60，DD20190159）；国家重点研发计划项目（2016YFC0600107）；山东省地质勘查项目（鲁勘字（2018）19号，鲁勘字（2019）1号） |
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| 摘 要： | 笏山金矿床为陡崖断裂带南段内最大的金矿床，为了揭示其矿床成因，在矿床地质研究的基础上开展了矿体围岩元素地球化学和流体包裹体研究。研究结果表明：笏山金矿床沿NE向断裂发育大规模的热液蚀变带，地表出露的断裂带形成一个庞大的面形蚀变带，矿化较弱，分带不明显，钻孔显示金矿体两侧依次发育黄铁绢英岩、绢英岩化花岗岩蚀变带和二长花岗岩，金矿体主要产于陡崖断裂带下盘黄铁绢英岩蚀变带内。质量平衡计算表明：绢英岩化过程中，主量元素SiO2、Al2O3、FeO、MnO、Na2O、K2O、P2O5和部分稀土元素从二长花岗岩中迁出，而MgO、CaO、Fe2O3，成矿元素Au、Ag，亲硫元素Cu、Pb及亲铁元素V、Cr、Co、Ni迁入二长花岗岩；黄铁绢英岩化过程中，主量元素FeO、Fe2O3、MnO、MgO、CaO，成矿元素Au、Ag，亲硫元素Cu及亲铁元素V、Cr、Co、Ni迁入，SiO2、Al2O3、Na2O、K2O和P2O5迁出。岩相学观察、显微测温以及单个包裹体成分激光拉曼分析提示其流体包裹体类型主要为气液两相包裹体和含CO2三相包裹体，具有低盐度（w（NaCl）为5.33%~13.29%）和中温（260~300℃）CO2-NaCl-H2O体系，在成矿过程中，含矿流体经历了流体不混溶作用。结合矿床地质特征及实验结果分析，确定该矿床为受陡崖断裂带控制的中温蚀变岩型金矿床。
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| 关 键 词： | 笏山金矿床 热液蚀变 成矿流体 栖霞 胶东 |
| 收稿时间： | 2020-05-13 |
Geological and Geochemical Features of Hushan Gold Deposit in Qixia,Shandong Province |
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| Zhi Yunbao,Sun Hairui,Li Fenghua.Geological and Geochemical Features of Hushan Gold Deposit in Qixia,Shandong Province[J].Journal of Jilin Unviersity:Earth Science Edition,2020,50(5):1552-1569. |
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| Authors: | Zhi Yunbao Sun Hairui Li Fenghua |
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| Institution: | 1. Institute of Geological Survey, Shandong Province, Jinan 250013, China;2. Development and Research Center, China Geological Survey, Beijing 100037, China;3. Mineral Exploration Technical Guidance Center, Ministry of Natural Resources, Beijing 100083, China |
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| Abstract: | Hushan gold deposit is the largest gold deposit in the southern part of Douya fault. In order to reveal its genesis, based on the geological work of the deposit, the study of the surrounding rock element geochemistry and fluid inclusions of the ore body was carried out. The results show that a large-scale of hydrothermal alteration is developed along the NE-trending faults in Hushan Au deposit,with obvious surface hydrothemal alteration, low Au mineralization, and poor alteration zoning. The borehole logs show that the hydrothermal alteration along the Au ore-bodies is symmetrically developed, displaying sericite-quartz alteration and pyrite-sericite-quartz alteration with the increase of distance from ore-body. The ore-bodies are mainly hosted in the alteraltion zone of pyrite-sericite-quartz alteration at the footwall of Douya fault. The mass-balance calculation shows that the major and trace elements behaved complicatedly during fluid-rock interaction. In the stage of sericite-quartz alteration, Linglong biotite granite experienced the loss of SiO2, Al2O3, FeO,MnO, Na2O, K2O, P2O5, and enrichment of REEs and MgO, CaO, Fe2O3, Au, Ag, Cu, Pb, V, Cr, Co and Ni; in the stage of pyrite-sericite-quartz alteration, FeO, Fe2O3, MnO, MgO, CaO, Au, Ag, Cu, V, Cr, Co, and Ni enterred in the sericite- quartz altered granite, while SiO2, Al2O3, Na2O, K2O and P2O5 moved out. The petrographic, microthermometric, and laser Raman microspectroscopic analyses on the fluid inclusions show that the fluid inclusions are mainly two-phrase aqueous fluid inclusions and CO2-bearing three phase inclusions, which are low salinity (5.33%-13.29%) and medium temperature (260 to 300 ℃) CO2-NaCl-H2O system. The ore fluid experienced fluid immiscibility during the ore-forming process. We believe that the deposit should belong to mesothermal altered rock type Au deposit controlled by Douya fault, which is similar to Jiaojia Au deposit in Jiaodong area. |
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| Keywords: | Hushan gold deposit hydrothermal alteration ore-forming fluid Qixia Jiaodong |
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