Determination of sedimentation thickness within the Eastern part of Benue Trough, Nigeria from high resolution aeromagnetic data

Abstract

The estimation of basement depth within the eastern part of Lower Benue Basin was based on both Source Parameter Imaging and Spectral method of analysis of the high resolution Aeromagnetic data covering the study area. The total area covered is 18,150 km2 which include Markudi, Gboko, Otukpo Agena, Akwana, and Katsina-Ala, all in Benue state of Nigeria. The areais bounded by latitude 70 .00' and 80 .00' and longitude 8 0 .00’and 90.50’. The aeromagnetic data was subjected to Vertical derivative, Analytical signal, Source parameter imaging SPI) and spectral depth analysis. These derivatives help demarcate regions of relatively thick sedimentation and regions of basement rock outcrop and intrusions into sedimentary formations at shallow depth. Maximum depth of sedimentation from SPI method is 4.146 Km which is located at the Eastern edge below Akwana, depth in the range of 3 Km were also obtain at the Western edge below Gboko, Makurdi and around Agena. Shallow sedimentations were observed at the South Eastern and North Eastern corner of the study area. Result from the spectral depth analysis give depth values that varies from 2.36 Km to 5.42 Km. Results from these two methods correlate in location and value. Regions with depth estimate above 4 Km could be explored for hydrocarbon and gas exploration. The South-Eastern corner and the North-Eastern corner of the study area which depict consolidated lithology at relatively shallow depths can serve as locations for water reservoirs at the height of rainy seasons to avoid flooding.