基于已知信息约束的重磁三维反演在深部磁铁矿勘查中的应用——以安徽泥河铁矿为例  

The application of gravity and magnetic three-dimensional inversion based on known information constraint in deep magnetite exploration:A case study of the Nihe iron deposit in Anhui Province

作　　者：罗凡 严加永[2,3] 付光明[1,2,3] 

机构地区：[1]东华理工大学地球物理与测控技术学院,江西南昌330013 [2]中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室,北京100037 [3]中国地质科学院地球深部探测中心,北京100037

出　　处：《物探与化探》2018年第1期50-60,共11页Geophysical and Geochemical Exploration

基　　金：国家自然科学基金项目(41574133);中国地质科学院基本科研业务费专项经费(YYWF201526);中国地质调查局地质调查项目(121201103000150017);国家重点研发计划专项课题(2016YFC0600201)

摘　　要：安徽泥河铁矿是一个典型的玢岩型铁矿,矿体埋深大,在地表产生的重磁异常幅值较小。为评估重磁资料精细处理与三维反演在磁铁矿深部勘查中的应用效果,选择泥河铁矿开展基于已知信息约束的重磁反演试验:首先通过模型试验对比了不同已知信息约束条件下的三维反演效果,然后通过针对性的位场分离方法提取了泥河铁矿的剩余重磁异常,将已知的地表地质信息转化为物性信息,构建了剩余密度和磁化率参考模型,用以约束重磁三维反演。根据反演所得密度体及磁化率体的三维分布模型,结合物性与岩性之间的关系,确定了泥河铁矿体的三维空间形态,该结果与地质勘探结果基本吻合。研究结果表明,基于已知信息约束的重磁三维反演,可以大幅提高反演结果的可靠性,对于高磁高密度的磁铁矿而言,是寻找和刻画深部磁铁矿体的有效方法。The Nihe iron deposit is a typical porphyrite type iron deposit with large burial depth, small amplitude of gravity and magnet- ic anomalies generated at the surface in Anhui Province. The authors selected the Nihe iron deposit to carry out gravity and magnetic in- version experiment based on known information constraint, in order to evaluate the application effect of gravity and magnetic data fine- grained and three-dimensional inversion in magnetite deep exploration： First of all, through the model test, the authors compared the three-dimensional inversion results with different known information constraints, and then extracted the residual gravity and magnetic a- nomalies of the Nihe iron deposit through the targeted field separation method. Then, the authors transformed the known surface geolog- ical information into physical information, and built a remnant density and magnetic susceptibility reference model to constrain gravity and magnetic three-dimensional inversion. Based on the three-dimensional distribution model of inversion density and magnetic suscepti- bility body, the authors confirmed the three-dimensional spatial shape of the Nihe iron orebody, and found that the result is basically consistent with geological exploration results. According to the results, the reliability of the inversion results based on the known information constrained gravity and magnetic three-dimensional inversion could be improved. For magnetite with high magnetic and high density, this method is an effective method to find and characterize deep magnetite orebody.

关 键 词：泥河铁矿 重磁 三维反演 地质约束 

分 类 号：P631[天文地球—地质矿产勘探]