Determination of Sedimentary thickness over parts of Middle Benue Trough, North-East, Nigeria using Aeromagnetic Data

Abstract

High resolution aeromagnetic data acquired by the Nigerian Geological Survey Agency which covers about 18,150 km2 of some parts of middle Benue trough (that lies between Longitude 9oE 10oE and Latitude 8oN 9.50oN), was processed and interpreted with the goal of estimating the study area sedimentary thickness. Polynomial fitting of order one was used in regional-residual separation of the Total Magnetic Intensity map of the study area. Thereafter, analytical signal, source parameter imaging (SPI) and spectral depth analyses were applied on the residual data. Results from the analytical signal showed that the area is made up of highs and lows magnetic anomalies with varying amplitudes. The SPI result revealed a sedimentary thickness ranging between 101.8 m and 2550.0 m and the depth estimates from the spectral depth analysis showed that the sedimentary thickness of the study area ranges between 1.20 km and 3.20 km. The estimated depths from spectral analytical method were contoured to portray the basement isobaths for the study area. The highest sedimentary thickness from both depth analytic methods agreed in terms of location, this value can supports the hydrocarbon (gas) accumulation in the central and southern part of the study area