Surface Radiogenic Heat Distribution in Obio-Akpor Area of Rivers State, Nigeria

Abstract

Radiogenic heat production rates of soil samples from some selected sites in Obio-Akpor area of Rivers state, Nigeria are presented. Activity concentration of naturally occurring radionuclides: ⁴⁰K, ²³⁸U and ²³²Th in samples were determined using a NaI(Tl) gamma-ray spectrometer. Radiogenic heat production rates calculated from activity concentrations ranged from 0.2 to 11.2 pW/kg for⁴⁰K, BDL to 178.2 pW/kg for ²³⁸U, and BDL to 958.8 pW/kg for ²³²Th. Total heat production varied from 102.1 to 1086.0 pW/kg. As much as 90% of total heat production is from ²³²Th, while ⁴⁰K and ²³⁸U contribute 1% and 9% respectively. Heat production is higher than that of a region in the south-western part of the country but lower than that from the northern part.