Sediment Thickness Distribution And 2d Depth Model Of The Ikom Basin, Southeastern Nigeria, Using High Resolution Aeromagnetic Data

Abstract

This study, necessitated by the availability of high resolution data, presents sediment thickness distribution of Ikom Basin in southeastern Nigeria and a depth model of a profile across the basin, by analysing aeromagnetic data obtained from the Nigerian Geological Survey Agency (NGSA). The magnetic survey method is a cost effective non-invasive tool for investigating the bottom boundary of sedimentary basins. The method of study involved processing total magnetic intensity (TMI) data with source parameter imaging and standard Euler deconvolution for depth estimation. Power spectrum analysis was also carried out to obtain a cut off, used in designing the low pass filter which generated regional magnetic field. From the regional field, a profile was digitized and modelled. The results for sediment thickness estimation show that depth to basement surface is less than 100 m to over 5000 m with the central portion of the Ikom Basin being deepest. The western and eastern extremes of the basin are intruded having depth values ranging 0 – 150 m. Also, the 2 D inverse model of a SW - NE profile through the central part of the basin has sediment thickness of 1 – 4 km, a width of 30 km overlying intruded metamorphic basement. This knowledge about sediment thickness distribution can be applied in various aspects of geological studies including petroleum, geothermal, and mineral exploration. For petroleum investigation, the depocenter of the basin is the central part where thickness is over 5000 m.