Geophysical Investigation of Radiometric Data of Igumale and Nsukka, Southern Nigeria for Possible Spots of Radiogenic Heat Generation

Abstract

Objectives: High-resolution aero-radiometric data of Igumale and Nsukka of Southeastern Nigeria, were used in this study to ascertain the local proportion levels of uranium (U), thorium (eTh) and potassium (K). Methods: Obtained data were grid and subjected to Geosoft analysis using Oasis Montaj Package. Findings: The analysis's findings showed that the potassium concentrations vary from 0.00% to 0.6%. The average thorium concentration was 13.6 ppm, having value spanning from 4.3 to 22.9 ppm. The uranium concentration level varies between 0.5 to 7.0 ppm with average value of 20.86572 ppm. There is a very clear discountunity seen in the middle of the research area trending north to south allowing the passage of low concentration of all three radioactive substances towards the southeastern region. The ternary map revealed radioactive mineral compositions which are exceedingly high in the southeastern part and associated with Esh and Arish formation resulting from felsic volcanic rock deposits greater than the usual average value of radioactive materials a reliable geothermal energy source in the environment. The low concentration combined effect of the three radioelement falls within longitude 7o20ʹ to 7o40ʹ and found in areas within the false bedded sandstone, coal and shale (FSS), sandstone (ESS), coal, sanstone and shale (LCM) formation where as high concentration combined effect is located within latitude 6o30ʹ and 6o47ʹ and longitude 7o47ʹ and 8o00ʹ are associated with Esh and Arish formation. Spot for RHP is seen to be very high in the north western and extending towards the south eastern part of the study area whereas low radiogenic heat production (RHP) is evident at the boundary between Nsukka and Igumale central part of study area trending NS between longitude 7o 30ʹ and 7o 60. Novelty: The research revealed spot of high RHP which will guide geoscientists, miner and investors in choosing the optimal locations for installing an exploratory well to harness high generated heat. Keywords: Aeroradiometric, Radioelements, Igumale-Nsukka, Total count map, Ternary map, Radiogenic heat production