Centre for exploration targeting and analytic signal techniques as tools for interpretation of aeromagnetic data: emphasis on parts of Mid-Niger basin, Nigeria

Abstract

Ten aeromagnetic data sheets (each measuring about 55.74km2) covering some parts of Mid-Niger Basin, Nigeria and situated within latitude 8⁰00'N - 10⁰00'N and longitude 4⁰30'E - 7⁰00'E were acquired from the Geological Survey Agency of Nigeria and interpreted, using Oasis Montaj software. The data was digitized and assembled to produce a joint aeromagnetic data file for the area. The data was first reduced to pole and then subjected to CET grid analysis and analytical signal methods. The result of application of the CET phase symmetry grid analysis to the Total Magnetic Field Intensity data revealed the line-like regions of discontinuity and lineaments within the study area. The result of the amplitude domain analytic signal shows high amplitudes, ranging from 0.344 to 0.218 cycles which might be due to outcrops of magnetic rocks while intermediate structures have amplitudes ranging from 0.218 to 0.096 cycles could be areas of shallow intrusions of magnetic rocks into the sedimentary basin. The regions with the lowest amplitudes ranging from 0.096 – 0.064 cycles connote regions of deeper magnetic rocks at the basement depicting the trending of the basin in a NW-SE direction. The line-like regions and lineament features as well as the low amplitude regions could serve as migration and depositional environments for minerals and hydrocarbon accumulation respectively.