Mapping and Identifying Two Types of Geological Features from Enhanced Derivatives of Aeromagnetic Data: A Case Study from Northwest Inner Mongolia

With difficulties of finding outcrop mines increasing, mineral explorations go to sedimentary cover areas, however, geological features of rocks and structures which are the dominant control to ore deposits hidden deeply beneath sedimentary cover are difficult to identify especially in the absence of seismic or electrical methods. Magnetic edge detection methods help find structures and boundaries of anomalous geological features. Still, there are gaps between geophysical edge detection results and geological demands, that is all edge detection results sharpen boundaries without distinguishing the sub-circular boundaries of anomalous geological rocks and blocks from the sub-linear boundaries of anomalous geological layers and fault structures, as these two types of geological boundaries would determine and influence mineral systems differently. Trying to improve this issue, we present a combined analysis approach of edge detections to identify the two key types of geological boundaries. Firstly, we initiated the approach by applying four generally accepted methods to detect geological feature edges. Secondly, we analysed and interpreted edge detection results according to combining and integrating the characteristics of each employed algorithm. Finally, we present the geologic sketch map, which shows the distribution of inferred geological rocks and structures based on the combined analysis of aeromagnetic data in a thick sedimentary cover area of northwest Inner Mongolia. Our geologic sketch map may be helpful for further studies of Inner Mongolia and our combined analysis approach may be useful for other coverage geological boundary identifications.