基于GIS的层次分析法在张家口北部地区金矿成矿预测中的应用

Application of GIS-Based Analytic Hierarchy Process for Minerogenetic Prediction in Northern Zhangjiakou Region

以地理信息系统(GIS)为平台,对张家口北部地区进行金矿成矿分析后认为,太古宇桑干群谷咀子组(Arg)、红旗营子群(Ar3H)和元古宇长城系常州沟组—高于庄组(Chc-g)为成矿的有利地层组合;金矿床(点)多出现于岩浆岩体外接触带;半径为0.75～1.50km的断层影响带为最佳的有利成矿的断层影响范围;Au、Ag、Cu、Zn化探异常,重砂异常,多元素水系沉积物异常为成矿的有利地球化学元素异常组合;遥感解译的蚀变区和环形构造缓冲区影响带为有利的成矿部位。利用GIS的空间分析功能分别提取了地层、岩体、断裂、化探、遥感等16个分析因子,建立了层次分析模型并根据该区成矿概率的分布进行了成矿远景区的预测,共圈出了18个成矿远景区,其中预测远景区3,4,5,6,7覆盖了大部分已知金矿床(点),而预测远景区2,8,10,11,14,15,18目前还未发现金矿床(点),预测结果对于该区的进一步找矿具有一定的指导意义。

This paper analyzes comprehensively the gold mineralization in northern Zhangjiakou region, with GIS （geography information system） as platform. It reveals that Archeozoic Sanggan Group Gujuzi Formation（Arg）, Hongqiyingzi Group（Ar3 H） and Proterozoic Changchengian system Changzhougou Formation-Gaoyuzhuang Formation（Chc-g） are the combination of benefit strata, while the gold deposits are mostly located in magmatic segregation of outer contact aureole of terranes. In addition, a fault influence belt with a radius about 0.75-1.5 km is the best area for mineralization. It is found that Au, Ag, Cu and Zn, heavy sand concentration anomaly and multi-element water system sediments are the beneficial anomaly of chemical element combination. Favorable areas for mineralization are the erosion and faulting zones interpreted by remote sensing. With the spatial analysis of GIS, these favorable factors are extracted so as to build the analytic hierarchy process. The 16 factors chosen for the analysis include strata, terrane, fault, geochemical anomalies of Au, Ag, Cu, Zn, and remote sensing ,etc. Finally, based on the analysis, favorable area are predicted according to the ore formation probability values. The prediction shows 18 minerogenetic prospective areas. In these areas, 3,4,5,6 and 7 have almost covered all known gold deposits and 2,8,10,11,14,15 and 18 have not yielded gold deposits, which should be specially emphasized. It is believed that the prediction result can be a good reference for further ore-finding of this area.