Structural delineation and identification of mineralisation zones using Aeromagnetic data in Katsina State, Northwestern Nigeria

Abstract

Eight High-resolution aeromagnetic data (HRAM) were used to delineate subsurface structures and identify potential mineralisation zones in parts of Katsina State, northwestern Nigeria, the data sets are specifically Sheet 33 (Ruma), Sheet 34 (Katsina), Sheet 55 (Dutsin Ma), Sheet 65 (Musawa), Sheet 78 (Funtua), Sheet 79 (Malumfashi), Sheet101 (Maska) and Sheet 102 (Zaria). Four edge-detection techniques including Analytic Signal (AS), First Vertical Derivative (FVD), Second Vertical Derivative (SVD), and Horizontal Gradient Magnitude (HGM) alongside the Centre for Exploration Targeting (CET) plug-in, were applied to map lineaments such as faults, dykes, and folds. The Total Magnetic Intensity (TMI) map revealed significant variations (32,933.563-33,079.871 nT), with high magnetic anomalies associated to ferromagnetic rich lithologies, including porphyritic granite and hypersthene quartz diorite. Structural trend analysis using rose diagrams revealed dominant WNW-ESE and NE-SW orientations, consistent with regional Pan-African tectonics. High AS amplitudes (0.091-0.259 nT/m) and high structural density zones correlate with potential mineralisation zones, particularly in the southeastern (Mai-Jiriya, Gwarzo) and northwestern (Charanchi, Mani) regions. A prominent NW-SE trending dyke-like feature through Mahazu and Ungwan Gagarau was identified as a structurally controlled mineralised corridor. Overlaying structural maps with geological data confirmed mineralisation within pelitic/muscovite schist and porphyritic granite, likely driven by magmatic intrusions. These findings demonstrate the efficacy of aeromagnetic surveys in mapping structural controls on mineralisation, providing a framework for targeted exploration in Nigeria’s Schist Belt. Ground geophysical surveys and geochemical assays are recommended to validate these zones and assess economic potential.