STRUCTURAL CHARACTERIZATION OF MIDDLE BENUE TROUGH, NIGERIA USING AEROMAGNETIC, RADIOMETRIC AND DIGITAL ELEVATION DATA

Abstract

Detailed structural analysis was conducted over parts of the Middle Benue Trough usingaeromagnetic data acquired from the Nigerian Geological Survey Agency (NGSA). The data was analysed using Geosoft Oasis Montaj and Esri ArcGis Pro. The aeromagnetic data was compiled into a grid and colour map. Different filters were then applied to the total magneticintensity (TMI) grid and the results were compiled equally into grids and colour maps. Elevation and aero radiometric data over the area, also compiled into grids and colour maps were used to constrain the structural analysis and interpretation of the result. The result of the structural analysis and interpretation revealed structures typical of rift basins. There are numerous intra basin, large scale and medium scale normal faults, with two easily recognizable zones of accommodation. Identified from the map interpretation was also a deep trough flanked by intra-basin basement highs. There was also evidence of magmatic intrusionswhich appear as small wavelength magnetic anomalies on the TMI map. Estimation of depth to magnetic sources using the source parameter imaging (SPI) technique shows a range of 0.33 to 4.67 for the sources. Pseudo-two-dimensional depth modelling confirms the influence of tectonic evolution of the study area on present-day surface and subsurface geomorphology.