Magnetic basement depth from high-resolution aeromagnetic data of parts of lower and middle Benue Trough (Nigeria) using scaling spectral method

Abstract The high-resolution aeromagnetic data of parts of the lower and middle Benue Trough (Nigeria) has been analyzed to estimate the magnetic basement depths using the scaling spectral method. Magnetic basement depths beneath the area of study are found dominantly between 3 km and 5 km with the 3 km depths corresponding to the areas of Ogam/Obangedde, Ugba and Makurdi whereas the 5 km depths are found around the areas of Abakaliki, Gboko, Igumale, Oturkpo, Gbajimba and Arufu. Shallower magnetic basement depths of 1 km are estimated around Ebeel and the area of Ugba and 2 km depths from the areas of Akwana and Otukpa. We have also calculated few higher values of 6 km around the areas of Igbor, near Igumale and the area north of Oturkpo, 7 km depths at Onuweyi and Ikumbur areas and 9 km depths near Makurdi, Yandev area and east of Ogoja area. Our estimated basement depths are in good agreement with the results of the earlier studies in the region. The obtained scaling exponent values are found between 0 and 3 and are not correlated everywhere with the estimated depths and the geology of the region. That may be because of the effects of adjacent geological units and the presence of the volcanic intrusions within the region.