Spectral Re-Evaluation Of The Magnetic Basement Depth Over Parts Of Middle Benue Trough Nigeria Using HRAM

Abstract The new high resolution aeromagnetic data have been used to re-evaluate parts of the Middle Benue Trough Nigeria using spectral analysis technique in order to appraise the hydrocarbon accumulation potential of the area. The regional field was separated with a first order polynomial using polifit program. The residual data was subdivided into 16 spectral blocks allowing spectral probe of 12.5km by 12.5km area for 15minute by 15minute windowing using OASIS MONTAJ software program. Two prominent magnetic depth source layers were identified. The deeper source depth values obtained ranges from 2.33km to less than 5.66km with an average depth of 3.65km as the magnetic basement depth while for the shallower sources the depth values ranges from 0.07km to less than 0.42km with an average depth of 0.21km. The shallow depth source is attributed to the volcanic rocks that intruded the sedimentary formation and this could possibly be responsible for the mineralization found in parts of the study area. The significance of the magnetic depth value indicate that the sedimentary layer of the Albian Age Coniacian - Turonian Age and Turonian - Senonian Age is thick enough to generate hydrocarbon if other conditions are met.