Determination Of Magnetic Basement Depth Over Parts Of Middle Benue Trough By Source Parameter Imaging SPI Technique Using HRAM

Abstract The new high resolution aeromagnetic data of parts of the middle Benue trough Nigeria have been analysed to appraise its hydrocarbon accumulation potential using Source Parameter Imaging SPITM technique. The regional-residual separation was done with a first order polynomial using POLIFIT program and this lead to the residual field data that corresponds to the target sources for further processing. The preliminary qualitative interpretation revealed that the area is made up of low frequency anomaly and high frequency anomaly sources related to deep and shallow seated bodies which are possibly areas of deeper and shallower sediments. The general trend in the orientation of the magnetic contour closures are found to be predominantly in the NE-SW direction an attribute of the Pan - African Orogeny trends. Quantitative analysis of the study area using SPI revealed two main magnetic anomaly sources depth represented by the long spikes deep blue coloured and the short spikes light green and orange colored. The long blue spikes are areas of deeper lying magnetic bodies hence with thicker sedimentary cover and ranges from 2000m to 6291.5m with an average depth of 3245m and could be viewed as the magnetic basement depth of the studied area. The short spikes are areas of shallow seated magnetic bodies hence are areas of thinner sediment ranging from 159.067m to 2000m with an average depth 1079.5m. They may be regarded as magmatic intrusions into the sedimentary basins and these may be responsible for the Lead-Zinc mineralization found in the area. Several undulations found on the basement surface may likely act as trap. The significance of these results indicate that the marine sedimentary layer of the Albian Age Coniacian - Turonian Age and Turonian - Senonian Age have the potential to generate hydrocarbon if other conditions are met.