内蒙古集宁覆盖区元素地球化学异常识别新方法研究

Mineral prospecting and exploration works gradually focus on regolith-dominated terrains, since geochemical anomalies on the surface of cover are weak and subtle, innovations of geochemical anomaly identification techniques are necessary. This study application in regolith-dominated terrains of Jining, Inner Mongolia aims at promotions of element geochemical anomaly identification techniques. In the study, we will try to use KL divergence as a quantitative analysis tool, to analysis and compare the patterns of covered terrain and outcrop zone, overburden with and without mineralization, overburden's surface and section on element concentration and singularity index. And attempt to verify the assumption of a pattern that singularity index of multi-element almost do not alter with the depth of measurement, media, or lithologies. Base on the knowledge of geochemical patterns, we will try to utilize the newly developed optimal filtering methods and principal component analysis to identify and integrate molybdenum mineralization associated geochemical anomalies in study area, and to develop a technique framework of geochemical anomaly identification in regolith-dominated terrains. This application of study would improve the development of geochemical anomaly identification, and provide evidences and references to the molybdenum deposits prospecting work in the study area.

当前的找矿工作主要聚焦于覆盖区，由于覆盖区地球化学异常有着“弱缓”的特点，覆盖区致矿地球化学异常的识别技术创新是当务之急。该申请以拓展现有地球化学异常识别技术为目标，以内蒙古集宁浅覆盖区为研究区，以KL散度为工具，定量化分析、比较并总结覆盖区与露头区、矿化与非矿化区、地表及剖面上，多元素地球化学数据在元素浓度及奇异性指数上的模式及这一模式随采样介质和采样深度的变化规律，验证元素奇异性指数在不同地质体、不同采样介质、不同采样深度也能保持稳定模式的规律。在此基础上，用最优滤波这一新方法和主成分分析对与钼矿化相关的奇异性异常进行识别与信息综合，并建立覆盖区地球化学异常识别方法技术流程，以期推动地球化学异常识别技术的发展，为该区钼矿找矿工作提供参考依据。

内蒙古集宁地区广泛覆盖玄武岩、黄土等覆盖层，造成了地表弱缓的地球化学异常，给找矿工作带来了难度。 本项目通过野外考察、样品分析、计算机模拟、数据分析等手段试图解决这一问题。研究发现了玄武岩裂隙中存在着微量元素异常，覆盖层中矿化相关元素浓度随着离基岩的距离增大而逐渐增大的规律。提出基于相对熵的层次聚类模型，基于该方法验证了内蒙古达来庙地区奇异性指数在不同地质体中有着较为稳定模式的规律，并且第四系覆盖层和下伏地层有着相似的模式。通过蒙特卡洛模拟方法，分析了主成分分析在不同条件下合成矿化相关信息的效用，提出了主成分分析结合局部奇异性分析这一在覆盖区识别矿化异常的方法组合。结合以上成果，在内蒙古集宁地区识别了弱缓异常，发现了小大青山-红娘山隐伏半隐伏成矿带，结合其他项目资源，规划找矿远景区，布置钻孔并见钼矿化。