Radiometric Characterization of Idoani Basement Complex Rocks, Southwestern, Nigeria

The radionuclides and Radiometric assessment of the rocks in Idoani basement complex in Ondo state, Southwestern, Nigeria were carried out with a view to determine the level of radioactive materials in the rocks. The radiometric ground survey was carried out using a very sensitive Sodium Iodine Scintillation Counter, Scrintex Model SGL-ISL with the serial number 8001089.The analysis for the radionucluides such as uranium, thorium and strontium(in ppm) was done by instrumental Neutron Activation Analysis (INAA) at the department of applied geology,Federal university of technology, Minna, Niger state, Nigeria, using the method of Brunfelt and Steines,1969 at Geology laboratory of Victoria university,New Zealand. The results of the radiometric ground survey shows the anomalous radiometric counts observed in the granites(1690cps) and granite gneiss(1650cps) as compared to the low radiometric counts ((940-1300cps) observed in the metasedimentary rocks.The overall radiometric assessment showed that the mean activity concentration of Uranium-238, Thorium-232,Strontium-87,Vanadium-50.8, Cobalt-589 and Rubidium-87 in the metasedimentary rocks(quartzites,phyllites and quartz mica schists) conformed to the world acceptable range of (Th(15.38),Sr(2.90),V(10.20),Co(4.90) and Ru(38.0). This study showed that the granite and granite gneiss of the study area might likely posed environmental hazards if used for any domestic and human consumption purposes such as grinding stones and foundation gravels and may be harnessed as potential Hot Dry Rock(HDR) geothermal resources.