Evolution of Gongola Basin upper benue trough northeastern Nigeria

Abstract

Nine aeromagnetic maps of 1/2°×1/2° between longitude 10°00' and 11 °30'E and latitudes 09°30' and 11°00N representing part of the Gongola Basin, were analysed to determine some characteristics of a prominent aeromagnetic anomaly within the basin. The maps were digitised along flight lines and the data were interpolated on to a regular grid of 0.01° interval. The regional field of the area was approximated to a first order degree polynomial using the robust method. Depths to the first, second and third magnetic levels of the area were determined using the spectral analysis technique. Analysis of the nine blocks of 51×51 residual data points revealed two magnetic levels for some of the blocks while others have three magnetic levels. The first level has an average value of 1.25 km, while the second level has a mean value of 4.03 km, the third magnetic level has an average of 5.39 km. Three profiles covering a prominent anomaly in the area were selected for modeling. The GM-SYS 2'1/2 dimensional modelling programme was used to model the body. The depth to the causative body is between 2.40 and 8.09 km. The causative bodies were interpreted to be basic to ultrabasic rocks. Based on the results obtained, a rift origin was proposed for the basin. © 2010 Academic Journals Inc.