Multiscale analysis and 3D inversion modelling of aeromagnetic data for mapping BIF-hosted iron deposits in the Djadom-Eta area, Southeastern Cameroon

Abstract

This paper deals with the lithological association and geometrical relationship between highly related magnetized bodies in the Djadom area located in the southeastern Cameroon and the North-west (NW) part of the Congo craton, which is poorly documented. To address the issue, a combined approach that involves multiscale (Residual Magnetic Intensity (RMI) and horizontal Gradient magnitude(HGM)) at different altitudes, analytic signal and three-dimensional (3D) inversion modeling were performed on aeromganetic data via Geosoft software. The application of multiscale method to the RMI and HGM at different altitudes highlights structural features and geometrical magnetic source bodies from a shallow to a depth of 6 km. Furthermore, three major WSW – ENE, WNW – ESE and W – E striking faults correspond respectively to the Djadom, Eta, and Dja faults. The analytic signal revealed high magnetization bodies along the structures. The 3D inversion model highlights high susceptibility (S > 0.02 SI) dome-like bodies that are scattered and a lower susceptibility (S < 0.02 SI) sedimentary formation associated with Djadom and Eta faults. The highest susceptibility dome-like magnetized bodies could correspond to Banded Iron Formation-hosted (BIF) formations, whose geometry was inherited from Archean tectonics ascribed to vertical tectonics that affected the study area. During mineral exploration and subsurface geophysics, these aeromagnetic maps are an important tool for geological mapping and for identifying mining targets.