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概率图法在筛分混合分布的问题上,只能对混合分布的各项参数作出粗略的估计.为了解决这一问题,引入了MML-EM法.模拟研究表明,在混合分布参数估计上,该方法比概率图法有更高的精度.以江西大吉山钨矿石英脉原生晕数据为例,经过该方法的筛分,得到钨、钽和铌的含量服从由2个子分布组成的混合对数正态分布,即双峰分布.结合前人的地质研究,可以初步得出结论:钨的高值总体代表了岩浆期后热液成矿期的热液充填石英脉型矿化,低值总体可能代表其他成矿期的事件,其中高值部分可能构成岩浆晚期浸染型的弱钨矿化.钽和铌的高值总体代表岩浆晚期的浸染型富矿化,低值总体代表其他成矿期的叠加矿化.该方法为化探数据中混合分布的筛分以及解释多地质成因总体提供了一种良好的定量化工具.
In order to solve this problem, the MML-EM method is introduced in the probability map method to separate the mixed distributions.The simulation results show that in the estimation of the mixed distribution parameter, The method is more accurate than the probability map method.Taking Datangshan tungsten vein primary halo data of Jiangxi Province as an example, the content of tungsten, tantalum and niobium in the method is screened by the method, and the content of tungsten, tantalum and niobium follows a mixture of two sub-distributions Which is bimodal distribution.Combining with previous geological studies, we can conclude that the high value of tungsten generally represents hydrothermal quartz vein type mineralization during the hydrothermal mineralization stage after the magmatic period, and the low value The whole may represent other events during the mineralization period, in which the high value part may constitute the weak magma mineralization of late magmatic dissemination type.The high values of tantalum and niobium represent the dip magmatic mineralization in the late stage of the magma, while the low values represent the other mineralization stages This method provides a good quantitative tool for the screening of mixed distributions in geochemical data and for the interpretation of multi-geological causes in general.