综合找矿方法在覆盖区的应用——以山东省单县大刘庄铁矿勘查为例

山东省铁矿分布广泛，在鲁西南广大覆盖区产有许多铁矿床，其中在菏泽市单县地区发育沉积变质型铁矿。简要介绍了单县大刘庄铁矿区的地质特征：该矿床埋藏于第四系-古近系巨厚层（覆盖厚度达458～549 m）以下，赋存于新太古代泰山岩群山草峪组中；区内铁矿体总体呈层状、似层状、透镜状，产状与围岩一致，走向为NW-SE，总体倾向SW，倾角为45°～60°；铁矿中全铁平均品位约25%，磁性铁平均品位约20%。详细介绍了运用地质、物探等勘查方法进行找矿的过程：通过对区内的物探数据进行分析，解译了矿区基岩的地质特征和隐伏断层的重要信息；根据大比例尺地质、物探示矿信息特征，建立了包含地质环境、矿床特征和地球物理特征（明显高磁异常和高重力异常及其梯度带）的预测模型；通过对大刘庄铁矿的勘查，总结出了在厚大覆盖层下铁矿床的勘查流程:“航磁异常选区→资料全面系统收集→工作区优选→磁法测量和重力测量→地质信息分析→大比例尺高磁和重力剖面、CSAMT和SIP测量→通过优选成矿有利部位→深部钻探施工→井中磁测”。

Application of Integrated Ore Prognosis Method in Covered Area:A Case Study of Shanxian Iron Deposit in Shandong Province,China

There are many iron deposits under the covered area in southwest of Shandong province. In Shanxian County of Heze City, the iron ores are sedimentary metamorphics deposits. These iron bodies occurs in the Shancaoyu formation of the Neo Archean Taishan Group, buried under Quaternary to Paleocene stratum with the thickness from 458 m to 549 m, appearing as stratum, stratoid, lenticular, and consistent with its surrounding rock, with occurrence of NW-SE strike, tendency SW of dip angle 45°-60°. The iron average grade is TFe 25% and mFe 20%. This paper introduced a prospecting process including geological methods and geophysical exploration methods in detail. With the help of the analysis from geophysical data in Shanxian County iron area, important geological information, such as the geological characteristics of bedrock, the buried faults, has been abstracted. Further with large scale geological information and geophysical information, a forecasting model that concludes geological environment, deposit characteristics and geophysical characteristics (higher magnetic anomaly, higher gravity anomaly, and its gradient zone) is established. Following the exploration of Daliuzhuang iron deposit under a thick stratum, a exploration flowchart is depicted as the following: aeromagnetic anomaly selection, comprehensive and systematic data collection, exploration areas selection, magnetic and gravity survey, analysis of the geological information, the large scale magnetic and gravity section survey, CSAMT and SIP survey, mineralization position selection, deep drilling exploration magnetic survey in drilling hole.