NATURAL RADIOACTIVITY STUDIES OF BASEMENT COMPLEX ROCKS AND QUARRY DUSTS NEAR AKURE, ONDO STATE, NIGERIA.
Adegbuyi, O. 1*, Ogunyele, A. C. 2 and Ademeso, O. A.2
1Department of Geological Sciences, College of Natural and Applied Sciences,
Achievers University, Owo, Ondo State, Nigeria.
2 Department of Earth Sciences, Adekunle Ajasin University, P.M.B 001,
Akungba-Akoko, Ondo State, Nigeria.
The effects of the natural radioactivity in crystalline rocks and quarry dusts from a quarry site in Shasha market within the basement complex area near Akure in Ondo State, Nigeria was investigated to determine the gamma count rate and concentration of the radio-elements such as Uranium (U) and Thorium (Th) in the rock units using a Geiger Muller Counter and Atomic Absorption Spectrophotometer (AAS) respectively. The average concentration of the radio-elements determined was 6.68ppm (U) and 27.17ppm (Th) for the rock samples and 3.31ppm (U) and 3.51ppm (Th) for the quarry dust samples. The enrichment of the radio-elements in the rocks and quarry dusts is a pointer to possible uranium and thorium mineralization in the granitic and pegmatitic rock bodies in the study area. The moderately high concentration of these radio-elements in the study area is also responsible for the high range of radioactive emission in the area (840 - 1820gc/s) which may be hazardous to the health of the quarry workers.
KEYWORDS: Akure, Quarry dusts, Radioactivity, Uranium, Thorium.