International Journal of Basic and Applied Sciences, 2 (1) (2013) 125-139 ©Science Publishing Corporation www.sciencepubco.com/index.php/IJBAS Geothermal and radioactive heat studies of parts of southern Bida basin, Nigeria and the surrounding basement rocks John U. Megwara 1 , Emmanuel E. Udensi 2 , Peter I. Olasehinde 2 , Mohammed A. Daniyan 3 & Kolawole M. Lawal 4 1 Nigerian Geological Survey Agency, P.M.B. 2007, Kaduna, Nigeria 2 Federal University of Technology, P.M.B.65, Minna, Nigeria 3 Ibrahim Badamasi Babangida University, Lapai, Nigeria 4 Ahmadu Bello University, Zaria, Nigeria *Corresponding author E-mail: megwarauj@yahoo.com Abstract Aeromagnetic and aeroradiometric data covering parts of southern Bida basin, Nigeria and the surrounding basement rocks were processed and interpreted. The research covered both basin and basement rock sections, and was aimed at determining the geothermal heat flow and radioactive heat characteristics of the survey area. The number of data points used for analysis were 2,937, obtained from the digitization of eleven ½ degrees by ½ degrees contour maps. Data processing methods used in the study include determination of heat from radiometric data, regional‒residual separation of the total magnetic intensity data, determination of depth‒to‒top and depth‒to‒bottom of magnetic sources and estimation of field scaling exponent using the Fractal technique. The research results gave geothermal heat flow values ranging from 69.167 mWm -2 to 124.821 mWm -2 with an average value of 90.959 mWm -2 and radioactive heat values ranging from 0.91 to 4.53 μW/m 3 with an average value of 2.28 μW/m 3 . Deductions made from the survey are, the field scaling exponent varies linearly with depth of downward continuation and Katakwa is a prospect area for geothermal heat. Keywords: Basement, basin, fractal, magnetics, radiometrics. 1 Introduction In recent years, combined airborne magnetic and radiometric surveys have been used as geological mapping tools, unless transported cover or abundant surface water render the radiometric data of little use. Airborne magnetic and radiometric data can be manipulated in a variety of ways, to minimize noise, enhance particular aspects of the data and integrate with other geoscience and geographic data. Typically, the ultimate goal is to produce an interpretation focusing on one or more particular problems that provides a reasonable and accurate depiction of geology. These problems include: provision of the third dimension to surface mapping and sampling, delineation of structures and alteration under a cover of overburden or water, geothermal exploration, research on radioactive heat, hydrocarbon survey, magnetic and radiometric minerals investigation using cost effective airborne measurements. Recent works by Nwankwo et al. [20] and Nwankwo et al. [21] have shown great potential for geothermal heat flow in the Bida basin. Hence, this study involves the interpretation of aeromagnetic and aeroradiometric data so as to determine the geothermal heat flow and radioactive heat features of the study area. 2 Geology of the study area The study area is shown in Figure 1, it is bounded by longitudes 4.5 o E to 8.0 o E and latitudes 8.0 o N to 9.0 o N, and has an areal extent of about 33,275 km 2 . The geology of the study area is shown in Figure 2; marked out in black outline. The southern Bida basin section of the study area; forms part of the larger Bida basin. The successions in the southern Bida basin consist of the basal Lokoja Formation, overlain by the Patti Formation and capped by the Agbaja Formation. The basal Lokoja Formation is a sequence of matrix supported conglomerates and sandstones overlying the Pre– Cambrian to lower Paleozoic basement. Depositional environments are predominantly within fluvial systems of a continental setting. The Patti Formation consists of dark grey carbonaceous shales; mudstones and siltstones