INVESTIGATION OF THE EFFECT OF HIGH CONCENTRATION OF RADIOACTIVE ELEMENTS ON GEOTHERMAL PARAMETERS WITHIN PARTS OF PLATEAU STATE, NIGERIA

Abstract

The study focuses on both quantitative and qualitative analysis of high resolution aeromagnetic data for the determination of geothermal parameters within parts of Plateau State. The result is correlated with the analysis of radiometry concentration data of the study area. The study area covers a total of 6,050 km2. Two areomagnetic data sheets were used which cover the major towns Naraguta and Maijuju. The study area is bounded by latitude 9°30'N to 10°00'N and longitude 8°30'E to 9°30'E. The aeromagnetic data was divided into sixteen blocks. Each of the blocks was subjected to Fast Fourier Transform analysis and then spectral analysis to determine the Curie depth within the study area. The modified Curie depth method was then used in evaluating the geothermal parameters. The region was found to have a shallow Curie point depth of 5 km which occurs at Southern edge of the study area. The heat flow of the study areas has values ranging from 10 to 170 mW/m2 with an average heat flow of 65.40 mW/m2. The regions with anomalous high heat flow ranging from 110 to 170 mW/m2 was obtained around Bawon Dodo, Dorowa Tsofo, Mangu and Dan Hausa of the study areas. The geothermal gradients also has a value ranging from 5 to 68 °C/Km with an average of 26.13 °C/Km. Correlating this result with analysis of the radiometric data, regions of high radioelement concentration did not correspond to region of high heat flow as expected. The high concentration of uranium, thorium and potassium measured within the study area must have arisen from the weathered in-situ basement rocks that give rise to the high geothermal gradient.