Correlation and mapping of geothermal and radioactive heat production from the Anambra Basin, Nigeria

Abstract

Twelve sheets of aeromagnetic and aeroradiometric data covered the study area. The data was used to investigate heat sources. The aeromagnetic data were combined to form a composite map-total magnetic intensity (TMI) anomaly map and aeroradiometric data of each radio-element were combined to produce the radioelements maps. Regional-residual separation of the total magnetic intensity data was performed using polynomial fitting method on the aeromagnetic data. The filtered residual data was Fourier transformed after dividing the whole area into thirty-five overlapping sections for spectral analysis, to determine Curie point depth, geothermal heat flow and magnetic trends. Calculation of ratios was used for the radio-elements to estimate the radioactive heat values in the study area, and the surface geology of the study area was delineated to outline each rock unit to match their density and corresponding radio-elements. The results of the analysis of aeromagnetic data showed that the shallow magnetic source ranges from 0.59 to 3.