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针对金属矿床成矿年代确定混乱的问题,国内外许多矿床学家和同位素地球化学家对金属矿物常规同位素定年方法进行了有益的探索研究,尤其是对于矿石矿物以闪锌矿、方铅矿和黄铁矿为主的铅锌矿床,硫化物矿物Rb-Sr同位素定年方法显示出了其独特的优势。结合近几年开展的工作,总结国内外硫化物Rb-Sr同位素定年研究取得的成果、闪锌矿中Rb、Sr的赋存状态与定年机理以及定年适应性问题。采用闪锌矿Rb-Sr同位素组成数据拟合成等时线源自热液流体与闪锌矿之间Rb和Sr的不同分异作用,但并不是所有的闪锌矿均适合该定年技术。要成功获得年龄,需结合野外地质特征采集代表性的矿石样品,并在镜下鉴定基础上挑选合适的单矿物;在分析测试过程中,需尽可能去除次生包裹体和粘土矿物。
Aiming at the problem of determining the confusion of the metallogenic age, many mineralogicalologists and isotope geochemists at home and abroad have made useful explorations and studies on the conventional isotopic dating methods of metallogenetic minerals, especially for the minerals of sphalerite, galena and Pyrite-based lead-zinc deposits, sulfide minerals Rb-Sr isotope dating method has shown its unique advantages. In combination with the work carried out in recent years, the achievements of Rb-Sr isotope dating at home and abroad are summarized, and the occurrence and dating mechanism of Rb and Sr in sphalerite and the dating adaptability are also discussed. The use of sphalerite Rb-Sr isotope composition data to fit the isochrons results from different differentiation of Rb and Sr between hydrothermal fluids and sphalerite, but not all sphalerite is suitable for the dating technique. To be successful, representative samples of ore are collected in combination with the geological features of the field and the suitable single minerals are selected on the basis of microscopic identification. Secondary inclusions and clay minerals should be removed as far as possible during the analysis and testing.