赣南盘古山钨矿隐伏花岗岩体岩石学与地球化学特征
Petrology and geochemistry of granite in the Pangushan tungsten deposit, south Jiangxi Province
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摘要: 著名的盘古山大型钨矿与深部隐伏花岗岩体具有密切成因关系，但因该岩体隐伏深，相关研究资料较为欠缺，很大程度上影响了对矿床岩浆-热液-成矿作用的深入认识。南岭科学钻探（SP-NLSD-2）揭露该岩体后，本文对其开展了岩石学和元素地球化学研究。结果表明，该岩体具有超酸性、富碱、贫钠富钾等特征，属于准铝-过铝质高钾钙碱性花岗岩。形成该岩体的花岗岩浆为高度分异演化的残浆，W、Bi等元素含量明显高于南岭燕山期花岗岩，为盘古山钨铋矿床的形成提供了丰富的矿质。岩浆演化至云英岩化阶段时，岩浆中的Mo、Bi、Cu、Pb及REE含量增加，而W、Sn含量则因已转移到岩浆期后热液而降低。岩体形成于板内伸展环境。Abstract: Pangushan granite is genetically related to the well-known Pangushan large-sized tungsten deposit. However, due to great depth, its petrologic and geochemical data had been lacking until it was discovered by the Nanling Scientific Drilling Project (SP-NLSD-2) recently. In this paper, the petrologic and geochemical study conducted by the authors is reported. The granite is found to be ultra-acidic, alkali-rich, Na-poor, K-rich, meta- to weak-peraluminous and K-high calc-alkaline. Its corresponding granitic magma is highly evolved and W and Bi values are significantly higher than their average values in Yanshanian granite in Nanling region, indicating that they were the major ore-forming material source. When the granitic magma was evolved to the greisenization stage, Mo, Bi, Cu, Pb and REE were enriched, while W and Sn were depleted because of their migration into the hydrothermal solution. The intrusion of the Pangushan granite happened during intraplate extension.
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Key words:
- geochemistry /
- granite /
- tungsten deposit /
- Nanling Scientific Drilling /
- Pangushan
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