Radioactivity and gamma ray spectrometry of basement rocks in Okene area, southwestern Nigeria | ||
| NRIAG Journal of Astronomy and Geophysics | ||
| Volume 9, Issue 1, January 2020, Pages 71-84 PDF (2.51 M) | ||
| DOI: 10.1080/20909977.2020.1711695 | ||
| Authors | ||
| M. A. Adabanija; O.N. Anie; M. A. Oladunjoye | ||
| Abstract | ||
| Abundant outcrops of crystalline rocks in the Okene area, southwestern Nigeria, suggest exposure of the inhabitants to gamma radiation. The power generation of the nation also remains a far cry from the required 20,000 MW, thus necessitating the need for alternative power supply. Therefore, the background radiation level and radiogenic heat potential of crystalline basement rocks in Okene were investigated using gamma ray spectrometry. This was accomplished by analysing 19 rock samples of different lithologies, namely banded gneiss, granite, charnockite, biotite granite, pegmatite and schist, collected from different locations of the Okene area for analysis which involved determining the concentration of U-238, Th-232 and K-40 radionuclides using a Canberra S100 multi-channel analyser with NaI(Tl) detector. The mean gamma radiation emitted on a lithological basis was in the order pegmatite > charnockite > granite > schist > banded gneiss > biotite granite and yielded an overall mean dose of 63.35 nGy/h corresponding to 3.11 mSvy annual effective dose equivalent. The computed radiogenic heat potential indicated banded gneiss has the highest potential, ranging between 0.964 and 1.407 μWm with a median of 0.964 μWm. Biotite granite has the lowest potential, varying from 0.774 to 1.014 μWm with a median heat-generation capacity of 0.894 μWm. The radiogenic heat production varied with lithology, whilst the background radiation annual dose equivalent was greater than the global average value of 60 nGy/h and the natural background radiation value of 2.4 mSvy. | ||
| Keywords | ||
| Gamma ray spectrometry; radiogenic heat potential; crystalline basement rocks | ||
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