白钨矿中微量元素的研究进展及其在矿床成因方面的应用

Research Progresses on Trace Elements in Scheelite and Their Applications for Genesis of Deposits

白钨矿(CaWO_(4))具高度耐物理和化学风化的性质,其晶体中的微量元素能记录重要的地球化学信息,对于反演岩浆和成矿过程具有重要意义。本文通过总结近年来国内外有关白钨矿矿物化学方面的研究成果,详细地论述白钨矿中微量元素的分布特征及其进入白钨矿晶格中的机制,以及微量元素在流体与白钨矿之间的分配行为。特别是,白钨矿中Mo元素的特征能反映成矿的氧逸度条件,而Eu元素不仅能够反映氧化还原条件,还能揭示成矿流体的pH值变化。此外,本文还讨论了白钨矿中微量元素与发光性之间的关系,以及白钨矿的同位素特征在地质定年和成因示踪中的应用。尽管白钨矿Sm-Nd定年法较为成熟,但误差较大;而近年来新开发的U-Pb年代学方法误差较小,但缺乏相关国际标样。最后本文评述了利用白钨矿解决矿床成因的具体应用实例以及相关的研究分析方法。这些研究说明,利用白钨矿中的微量元素特征可以在矿床成因分析、成矿潜力评价等方面发挥重要应用,也能为找矿勘查和成矿预测提供方法和依据。

Scheelite(CaWO_(4))has a strong resistance to physical and chemical weathering,and its crystal can record important geochemical information,which can be used to infer mineralization processes.In this paper,the distribution characteristics of trace elements in scheelite and their mechanism of entering the scheelite lattice,as well as the distribution behaviors of trace elements between fluid and scheelite,are discussed on the basis of recent research results on scheelite mineral chemistry.The characteristics of molybdenum in scheelite can reflect the oxygen fugacity of mineralization,and europium in scheelite can indicate not only the redox conditions but also the pH change of the mineralizing fluid.In addition,the relationship between the trace element content and the luminescence of scheelite is summarized.The isotopic characteristics of scheelite and their applications in dating and tracing are also introduced.The Sm-Nd dating method is quite mature,but the error is large.In contrast,recently developed U-Pb dating methods have shown good accuracy,but they lack international standards.Finally,the practical applications and related analysis methods of scheelite to address the genesis of deposits are reviewed.In summary,the characteristics of trace elements in scheelite can play an important role in analyzing the genesis of deposits and evaluating the metallogenic potential,and can provide the basis for prospecting exploration and metallogenic prediction.