interpretation of airborne radiometric data for possible hydrocarbon presence over bornu basin and its environs, northeast nigeria using thorium normalisation method

A new exploration technique called thorium normalisation method has been applied on the airborne radiometric data of thebornu basin and its environs to delineate favourable zones for hydrocarbon accumulations within the study area. this method issignificant because it indicates the probable presence of hydrocarbon in a sedimentary basin. separation of the radiospectrometricmeasurements over each lithologic unit and the estimation of the characteristic statistics of these units were carried out. the statisticaltreatment applied on the radioelements (k, eth and eu) of the study area shows a relatively low coefficient of variability (cv%)value for k, eth and eu signifying their high degree of homogeneity. the mean value of the radioelements (k ranging from 0.6 to2.0 %; th ranging from 9.6 to 15.9 ppm and u ranging from 2.2 to 3.8 ppm) obtained from the statistical analysis correlates with themean of natural radioelement (k ranging from 0.1 to 2.7 %; th ranging from 0.4 to 11.2 ppm and u ranging from 0.1 to 3.7 ppm)content of sedimentary rocks which corresponds to shale, the main source rock for hydrocarbon accumulation in the study area. thedrad (delineation of radioactive anomalies) result ranges from -0.77 to 1.83. the positive values are indicators of favourable zonesfor the presence of hydrocarbon accumulations. these results suggest that the preliminary information obtained from the use of thethorium normalisation method will guide the exploration of hydrocarbon in the study area.