 Corresponding author: Omenikolo IA Department of Physics/Electronics, Federal Polytechnic Nekede, P.M.B. 1036, Owerri, Nigeria. Copyright © 2022 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. Basement depth re-valuation of anomalous magnetic bodies in the lower and middle Benue trough using Euler deconvolution and spectral inversion techniques Ibe Alexander Omenikolo 1, * , Terhemba Theophilus Emberga 1 and Alexander Iheanyichukwu Opara 2 1 Department of Physics/Electronics, Federal Polytechnic Nekede, P; M; B; 1036, Owerri, Nigeria. 2 Department of Geology, Federal University of Technology, P; M; B; 1526 Owerri, Nigeria. World Journal of Advanced Research and Reviews, 2022, 14(02), 129–145 Publication history: Received on 21 March 2022; revised on 04 May 2022; accepted on 06 May 2022 Article DOI: https://doi.org/10.30574/wjarr.2022.14.2.0356 Abstract Spectral technique and Euler Deconvolution were applied to high-resolution aeromagnetic data of parts of Benue trough to estimate the depth of anomalous magnetic sources within the study area; Data enhancement techniques such as total magnetic intensity map, reduction to pole, regional-residual separation and upward continuation maps were employed to identify different magnetic anomalies, structural trends representing the tectonics of the location were observed trending NE-SW and N-S directions; The result of 3D Euler deconvolution for the structural index (SI) = 0, 1, 2, 3 gave depths to magnetic sources that range from -589;3 m to -2678;8 m, -459;0 m to -2691;9 m, -294;6 m to -2817;5 m, - 430;2 m to -2780;6 m respectively; The depth estimates from 2-D spectral revealed a two-layer model; The shallow magnetic depth ranges between 0;135 km to 0;200 km with a mean depth of 0;158 km and the depth to magnetic basement vary between 2;585 km to 4;878 km with a mean depth of 3;415 km; This result, therefore, indicates that the average basement depth of the study area obtained from the spectral analysis is 3;415km; This investigation, therefore provides appropriate sedimentary thickness for suitable hydrocarbon prospecting within the study area. Keywords: Basement depth; Spectral analysis; Upward continuation; Reduction to pole; Magnetic anomalies. 1. Introduction The magnetic survey is one of the most reliable tools used in geophysical surveys for the investigation of surface and subsurface geology. The magnetic method measures variations in the Earth’s magnetic field as a result of the anomalies in the geomagnetic field which are the resultant effects of the magnetic properties of the underlying rocks. It is applied for exploring hydrocarbon, minerals and for archaeological studies. In prospecting for oil, estimating depth to magnetic source bodies, possibly sediment thickness and in delineating subsurface structures. It is suitable for locating buried magnetic ore bodies due to their magnetic susceptibilities [16]. The aeromagnetic method has exhibited a remarkable role as regards quick coverage, rapid speed, reduced cost and having access to inaccessible terrains [4,7,40]. The technique has also been noted as a principal mapping tool for materials that are strongly magnetized [18]. Magnetic data are very effective in indicating the presence, delineating the boundaries, and determining the depth of igneous rocks [9,35,36]. Estimation of relief on the basement surface may be related to structures that harbour hydrocarbon in overlying sedimentary basins [8]. Several studies have been carried out for the estimation of depth to the basement using the spectral inversion method and 3D Euler Deconvolution [8,13,15,23-24,30-32,44,47,49,50]. Ofoegbu [51] estimated the thickness of the sediments in the Lower and Middle Benue Trough to vary between 0.5 and 7.0 km. Ekwok et al. [8] evaluated the depth to magnetic sources in parts of Southeastern Nigeria, standard Euler deconvolution, source parameter imaging, spectral depth analysis and two dimensions (2-D) forward modelling was applied to the airborne magnetic data. The results from the techniques