Michalis Tzortzis | Searcharxiv

arXiv2004

Natural radioelement concentration in the Troodos Ophiolite Complex of Cyprus

High-resolution gamma-ray spectrometry was exploited to determine naturally occurring thorium (Th), uranium (U) and potassium (K) elemental concentrations in the whole area covered by the Troodos Ophiolite Complex of Cyprus. For that purpose, a total of 59 samples from surface soils and 10 from the main rock formations of the region of interest were analysed. Elemental concentrations were determined for Th (range from 2.5x10^-3 ppm to 2.0 ppm), U (from 8.1x10^-4 ppm to 0.6 ppm), and K (from 1.3x10^-4 % to 1.0 %). The average values (A.M +- S.D.) derived are (0.24 +- 0.34) ppm, (0.10 +- 0.10) ppm and (0.21 +- 0.24) %, for Th, U, and K, respectively, in the soils, and (0.52 +- 0.17) ppm, (0.17 +- 0.11) ppm and (0.49 +- 0.87) % in the rocks. From these values, a radioactivity (radioelement) loss of nearly 50% is estimated in the underlying surface soils due to bleaching and eluviation during weathering of the rocks. The measured Th/U ratio exhibits values between 2 and 4, whereas the K/Th ratio is highly variable ranging between 1.5x10^3 and 3.0x10^4.

physics.geo-ph↗

arXiv2004

Determination of thorium, uranium, and potassium elemental concentrations in surface soils in Cyprus

A comprehensive study was conducted to determine thorium, uranium and potassium elemental concentrations in surface soils throughout the accessible area of Cyprus using high-resolution gamma-ray spectrometry. A total of 115 soil samples was collected from all over the bedrock surface of the island based on the different lithological units of the study area. The soil samples were sieved through a fine mesh, sealed in 1000-mL plastic Marinelli beakers, and measured in the laboratory in terms of their gamma radioactivity for a counting time of 18 hours each. From the measured gamma-ray spectra, elemental concentrations were determined for thorium (range from 2.5x10^-3 to 9.8 micro g g-1), uranium (from 8.1x10^-4 to 3.2 micro g g-1) and potassium (from 1.3x10^-4 to 1.9 %). The Arithmetic mean values (A.M. +- S.D.) calculated are (1.2 +- 1.7) micro g g-1, (0.6 +- 0.7) micro g g-1, and (0.4 +- 0.3) %, for thorium, uranium and potassium, respectively, which are by a factor of three to six lower than the world average values of 7.4 micro g g-1 (Th), 2.8 micro g g-1 (U) and 1.3 % (K) derived from all data available worldwide. The best-fitting relation between the concentrations of Th and K versus U, and also of K versus Th, is essentially of linear type with a correlation coefficient of 0.93, 0.84, and 0.90, respectively. The Th/U, K/U, and K/Th ratios (slopes) calculated are equal to 2.0, 2.8x10^3,and 1.4x10^3, respectively.

physics.med-ph↗