消除背景影响的化探异常圈定方法——以张家口地区为例  

The elimination of background influence in the delineation of geochemical anomalies: A case study of geochemical data from Zhangjiakou area

作　　者：李随民[1] 魏明辉[2] 郝华金[3] 

机构地区：[1]石家庄经济学院,河北石家庄050031 [2]河北省地矿局第三地质大队,河北张家口075000 [3]河北省国土资源厅矿产资源储量评审中心,河北石家庄050000

出　　处：《中国地质》2014年第6期2083-2090,共8页Geology in China

基　　金：河北省教育厅科研项目(2010269);河北省国土资源厅项目(2011055547)联合资助

摘　　要：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。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.

关 键 词：化探异常 衬度值 岩性影响较大元素 张家口 

分 类 号：P632[天文地球—地质矿产勘探] P595[天文地球—地质学]