Distribution of radioactive elements of some rocks in South-western Nigeria

摘要

Rock samples obtained from two locations in parts of south-western Nigeria were studied to establish the distribution of U, Th and K, present in them. Field data were collected using a gamma ray scintillometer while laboratory studies on the samples included spectro-metric analysis, Nal(Tl) spectrometry and geochemical analysis (ICP-MS method]. Gamma ray scintillometric reading showed that the outcrops present in the study areas gave consistently higher readings than the overburden materials. The analysis of spectrometric data indicated the presence of other radio-nuclides which are different from the three principal radio-nuclides, ~(238)U, ~(232)Th, and ~(40)K. Results of the geochemical data revealed the presence of radioactive elements like Pb, Ce, La, Ti and Fe~(2+). This study showed that besides the presence of U, Th and K, other elements like Pb, Ce, La and Ti also contributed to the bulk radioactivity measured in rock samples at the study areas. Zircon, xenotime and possibly thorite are the main radioactive minerals present in the studied rocks.