Variation of luminescence sensitivity, characteristic dose and trap parameters of quartz from rocks and sediments

Abstract

We investigated the optically stimulated luminescence (OSL) and thermoluminescence (TL) characteristics of quartz from sediments and parent rocks across South America. OSL and TL sensitivities were compared with the characteristic dose of dose response curves. Additionally, we estimated electron trap parameters of quartz from sediments with contrasting OSL sensitivities. Our results show that the natural sensitivities of quartz OSL (initial 0.8 s) and TL (110 °C peak) are positively correlated and range over six and four orders of magnitude respectively. The corresponding characteristic doses range from around 30 Gy–3000 Gy for dose response curves described by a single exponential function. Quartz from igneous and metamorphic rocks and Andean short-transported sediments report low-sensitivity OSL and high characteristic dose. The studied initial OSL signal has significant contribution of medium and slow components in quartz from rocks and Andean short-transported sediments, while in quartz from Brazilian long-transported sediments, the initial OSL signal is dominated by the fast component. The trend of sensitivity increase and characteristic dose decrease is attributed to the relative contribution of medium and low components to the initial OSL emission. Regarding the electron trap parameters, high, medium and low sensitivity quartz has statistically similar values of the activation energy and the frequency factor, but both parameters have larger variations in medium and low sensitivity quartz.