Justifying Ground Magnetic Follow-Up on Structural Lineament from Aeromagnetic Interpretation for Pegmatite Mineralization in the Thickly Covered Terrain of Nasarawa State, Nigeria
Keywords:
Pegmatite, Tilt Derivative, Lineament, Structure, Basement, LithiumAbstract
The global surge in lithium demand, driven by its indispensable role in renewable energy technologies and electric mobility, has positioned pegmatite-hosted lithium deposits as critical strategic resources. The Nasarawa region of North Central Nigeria, situated within the Pan-African reworked mobile belt of the Nigerian Basement Complex, hosts significant pegmatite mineralization; however, exploration efforts are impeded by extensive lateritic and sedimentary cover that masks surface expressions of mineralization. This study presents a ground magnetic follow-up investigation targeting structural lineaments previously identified from aeromagnetic interpretation to delineate structural features and zones considered prospective for concealed pegmatite-hosted lithium mineralization in the thickly covered terrain of Nasarawa State. Ground magnetic data were acquired using a GEM-19 Overhauser magnetometer system, with survey lines oriented perpendicular to the dominant NE-SW structural trend at 100 m line spacing and 20 m station spacing. Data processing included diurnal correction, IGRF removal, reduction to pole (RTP), and advanced enhancement techniques including first vertical derivative (FVD), second vertical derivative (SVD), analytical signal amplitude (ASA), and tilt derivative (TDR). Structural lineament extraction was performed using supervised digitization techniques to map faults, fractures, and structural intersections controlling pegmatite emplacement. The results reveal multiple episodes of structural brittle deformation and shearing, resulting in cross-cutting magnetic lineaments in varying directions, with dominant trends in NNE-SSW, NE-SW, NNW-SSE, and WNW-ESE orientations interpreted as fracture-controlled pegmatite intrusions. Integrating ground magnetic data with structural lineament mapping has identified potential mineralization pathways, providing a robust framework for targeting concealed pegmatite-hosted lithium mineralization in the study area.
