CAJ | 학술논문

由于不同成矿元素在不同岩性地层单元中的背景值存在较大差异，如采用符合正态分布的统计法计算元素异常下限值，会使得矿床可能并不分布在圈定的地球化学异常范围内，异常区可能仅是高背景岩石的反映。本文以张家口1∶20万化探扫面数据为例，圈定了Cu、Zn、V、Ti、Ni等受岩性影响较大元素的异常，结果表明传统统计方法所圈元素异常区受岩性控制作用明显。而考虑岩性本底含量的衬度值法所圈异常，不仅能有效避免岩性对异常的控制作用，且能在低背景岩石单元中圈出新异常，具有较好的找矿指示意义。
유우불동성광원소재불동암성지층단원중적배경치존재교대차이，여채용부합정태분포적통계법계산원소이상하한치，회사득광상가능병불분포재권정적지구화학이상범위내，이상구가능부시고배경암석적반영。본문이장가구1∶20만화탐소면수거위례，권정료Cu、Zn、V、Ti、Ni등수암성영향교대원소적이상，결과표명전통통계방법소권원소이상구수암성공제작용명현。이고필암성본저함량적츤도치법소권이상，불부능유효피면암성대이상적공제작용，차능재저배경암석단원중권출신이상，구유교호적조광지시의의。
As different geological bodies have different background values of metallogenetic elements, the ore deposit may be not distributed in the range of geochemical anomaly, and hence the anomaly might only reflect the background of the rock. Based on 1:200000 geochemical surveying data obtained in Zhangjiakou area, the authors calculated the anomaly thresholds of Cu, Zn, V, Ti and Ni elements. The results show that the geochemical anomaly based on traditional statistics is determined by the distribution area of basalt. That is to say, the range of geochemical anomaly is controlled by the lithology. According to the background value of different lithologies, the authors computed contrast values in comparison with geochemical data. The results show that this calculating way is not affected by lithology. This method can effectively delineate geochemical anomalies in low background value area. The contrast value method has good prospecting indicator significance.