铅同位素在矿床研究和找矿勘探中的应用综述

铅同位素用于示踪成矿物质来源已得到广泛应用,其方法主要有：模式年龄法、PbSL等时年龄法、构造模式法、Δβ-Δγ图解法以及直接对比法。其中单用模式年龄来示踪成矿物质来源已逐步淘汰,只能用通过合理模式计算的模式年龄来进行检验或佐证;铅构造模式因提出时没有考虑中国的地质问题而遭质疑;Δβ-Δγ图解法虽然考虑到中国的地质问题但仍需接受检验;而直接对比法是示踪成矿物质来源最有效、最直观的方法。此外,矿石全岩Pb-Pb等时线定年在一些矿床中应用获得成功,通过剔除系统样品中的后期干扰样品,可以使矿石全岩Pb-Pb等时线定年变得更加精确。铅同位素地球化学研究开始走向应用于化探与找矿评价,特别是运用铅同位素三维空间拓扑投影特征值V1和V2进行隐伏矿深度预测和资源量评价的铅同位素系统剖面化探方法,使铅同位素化探方法得到了新的发展。

A SUMMARY OF THE APPLICATION OF LEAD ISOTOPE TO STUDY ON ORE DEPOSITS AND ORE EXPLORATION

The lead isotope has been widely used in tracing of the ore source material including model age method, PbSL isochron age method, geotectonic model method, Δβ-Δγ graphic method, and the direct comparison method. Tracing the source material only by model age value has been phased out and the model age value must be calibrated with that calculated from the rational model. China geology was not involved in the Pb isotope geotectonic regime and now is questioned in China. Δβ-Δγ graphic method involves the geology of China but is under testing and verification. The direct comparison method is the most efficient and intuitive tracing method. In addition, the whole ore Pb-Pb isochron dating has been more accurate and applied successfully in a number of deposits through removing the late interference factors from the sampling system. Results of Pb isotope researches have been applied to geochemical exploration and ore potential evaluation, especially for application of the systematic Pb isotope geochemical profile method (three-dimensional projection topology value V1 and V2) to the prediction of concealed ore resources and deep blind ore bodies.