Interpretation of aeromagnetic data of Oyo area, Southwesthern Nigeria

The study presents aeromagnetic data interpretation which involves the interpretation of aeromagnetic data features. Due to Magnetic properties of the earth crust, aeromagnetic anomalies over Oyo town are evaluated to map the magnetic lineaments and estimate the depth to the basement. The aeromagnetic data, from the study area sheet 241 Oyo, acquired were subjected to various filtering and processing technique which in turn properly displays the magnetic anomalies and magnetic intensities. Butterworth was applied to improve the signal to noise ratio, to reduce magnetic equator to properly position anomalies and to remove grappling effects. Gaussian filter was also applied to remove the regional effects thus leaving only the residual anomalies. Other processing techniques such as Upward continuation of 500m, 1000m, 1500m and 2000m, derivatives in x, y directions, analytic signal to delineate magnetically active zones, averaged power spectrum, Euler Deconvolution. The result shows that the depth to the top of the deepest magnetic source of about 2.3 km, depth to the shallow source ranges from 0.25 to 0.5km The obtained data shows that there is an abundance of positive anomalies that correspond to the migmatite-gneiss complex which is of moderate intensity. Derivatives in x, y and z directions revealed the parallel to sub-parallel lineaments which generally trends NE-SW direction except for major lineament that cuts through the migmatite-gneiss complex which trends in NW-SE direction. All these observations were made from qualitative and quantitative data interpretations, which in turn support magnetic information of the area.