Structural Interpretation of Aeromagnetic Data Over Sheet 103 (Ikara), Northwestern Nigeria Using 3D Euler Deconvolution Technique

Abstract

The Nigerian Basement Complex is characterized by numerous extensive fractures, most of which are concealed beneath the surface. This research aims to identify and delineate these fractures within the north-central part of the basement complex and elucidate their tectonic evolutionary occurrence. To achieve this, High-Resolution Aeromagnetic Data (HRAD) of Sheet 103 (Ikara) were acquired and processed usingReduced-to-Equator (RTE), First Vertical Derivative (FVD), Analytic Signal, and 3D Euler Deconvolution techniques. These were used to interpret the characteristics of anomalous bodies and delineate regional fractures across the fracture and shear zones. The results revealed very low magnetic signatures of an anomalous region suspected to be a depression/trough sited between two prominent fractures trending NW-SW. These fractures exhibit moderate to high magnetic susceptibility, with depths ranging from 1.5km to above 2km. Results also reveal a curvilinear/semi-circular magnetic anomaly suspected to be a ring structure. However, the dominant fractures within the study area, trending WNE-ESE and E-W, exceed 1500 meters. The NW-SE regional fractures, as well as minor NE-SW fractures, evolved during the late-stage Pan-African Orogeny (600 ± 150 Ma). In contrast, the WNW-ESE and E-W trending fractures evolved during the Eburnean (1800± 2500 Ma) and Kibaran Orogeny (1100 ± 200 Ma). The results also reveal that the northern parts of the study area exhibit more fractures than the southern parts.