李小宇.甘肃省文县阳山金矿矿化花岗斑岩岩石地球化学特征[J].甘肃地质,2023,(1):10-19
甘肃省文县阳山金矿矿化花岗斑岩岩石地球化学特征
Petrogeochemical Characteristics of Mineralized Granite Porphyry in Yangshan Gold Deposit, Wenxian County, Gansu Province
  
DOI:
中文关键词:  阳山金矿  岩相学  岩石地球化学  矿床成因  甘肃文县
英文关键词:Yangshan gold deposit  petrography  petrogeochemistry  Gansu
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作者单位
李小宇 成都理工大学地球科学学院四川 成都 610059 
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中文摘要:
      阳山金矿位于扬子、中朝板块及松潘—甘孜褶皱带所夹持的三角区域内。本文对矿化—未矿化花岗斑岩进行了岩相学、岩石地球化学等方面的对比分析。结果显示,矿化与未矿化斑岩脉岩石地球化学特征不同,主量元素特征差异不大,同属富铝高钾钙碱性强过铝质花岗岩与花岗闪长岩系列,化学成分表现为高SiO2(69. 41% ~ 76. 85%)、富Al2O3(13. 73% ~ 17. 62%)、K2O(2. 05% ~ 4. 64%),贫Na2O(0. 05% ~ 4. 58%)。微量元素差异明显,矿化花岗斑岩脉Au-As-Ag-Sb-W含量明显偏高,尤其是Au、As较贫矿斑岩脉高出几个数量级,暗示富集成矿流体富集Au-As-Ag-Sb-W等低温热液元素。晚三叠世发育岩浆活动形成矿化花岗岩,其构造环境由环境洋壳俯冲向陆陆碰撞体系转化阶段,后经岩浆期后热液的叠加及交代作用,最终形成金矿体。
英文摘要:
      Yangshan gold deposit is located in the triangle region held by the Yangtze Plate, the China-Korea plate and the Songpan-Ganzi fold belt. In this paper, the mineralized and unmineralized granite porphyry has been analyzed in terms of petrography and petrogeochemistry. The results show that the geochemical characteristics of mineralized porphyry dikes are different from those of unmineralized porphyry dikes, and there is little difference in the characteristics of their major elements. Both porphyry dikes belong to aluminum-rich high-potassium calc-alkaline strong peraluminous granite and granodiorite series. The chemical composition of major elements is high SiO2 (69. 41% ~ 76. 85%), rich Al2O3 (13. 73% ~ 17. 62%), K2O (2. 05% ~ 4. 64%), and poor Na2O(0. 05% ~ 4. 58%). The content of Au-As-Ag-Sb-W in mineralized granite porphyry vein is obviously higher, especially Au(0. 21 × 10-6 ~ 5. 43 × 10-6)), As(453 × 10-6 ~ 10 000 × 10-6) is several orders of magnitude higher than Au (0. 01 × 10-6 ~ 0. 09 × 10-6) and As (8. 0 × 10-6 ~ 89. 4 × 10-6) of poor ore porphyry veins, suggesting that ore-forming fluids are enriched in Au-As-Ag-Sb-W and other low-temperature hydrothermal elements. In the Late Triassic, magmatic activity formed mineralized granite, whose tectonic environment changed from the subduction of the ambient oceanic crust to the transformation stage of the continental collision system, and after the superposition and metasomatism of the hydrothermal solution after the magmatic period, gold ore bodies were finally formed.
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