证据权法在成熟矿区进行成矿远景预测的尝试——以山西灵丘支家地铅锌银矿为例

Ore genetic prediction based on binary weights of evidence(wofe) modeling method——A case study of Zhijiadi Ag,Pb,Zn ore area,Shanxi Province

简要介绍了证据权模型的数学模型及GIS应用原理,尝试性地将该法引入到工作程度高的小范围矿区成矿预测工作中.在深入理解山西支家地矿区成矿特征基础上,通过了点阵化处理矿体、地质体的方法尝试性离散矿体和地质体,选取了符合条件的独立性控矿因子,优化提取了地层、线性构造,矿体和岩石界限等致矿证据层;以10 m×10 m为网格单元,分析了各证据层与矿体分布的空间相关性,定量计算了各证据层对矿化影响的对比值,使任意空间位置可能发生矿化的概率的计算成为可能,解释了各证据与成矿有利的相关程度,进而定量确定了该矿区各控矿因子对成矿有利程度,获得了断裂热液型矿体和隐爆角砾岩型矿体的成矿后验概率,并通过图形方式直观表达了成矿高概率区的空间分布,已知矿体与成矿高概率区有很高的吻合度,说明该方法在成熟矿区应用具有可行性.

The weights of evidence（wofe） modeling and it＇s applications based on GIS are described in the article.The modeling method is for the first time applied to the genetic prediction in small mature areas.The sensitivity of the Zhijiadi case is analyzed.The grid size used in the analysis was 10 m×10 m.Data of the spatial strata,structure and ore genesis are extracted from the studied area.Spatial relationship between the evidences and mineralization is analyzed,and contrasts are calculated.Ten evidences appropriate to the model are finally selected and converted into binary patterns,such as the strata unit,strata boundary of quartz porphyry,and proximity to the NE trending structure features.The posterior probability of each grid which reflects the degrees of mineralization is calculated.The special application of the wofe shows that the model is also adaptable to the zonation of mineralization.