Single-Grain Quartz OSL Characteristics: Testing for Correlations within and between Sites in Asia, Europe and Africa

Abstract

We studied the characteristics of the optically stimulated luminescence (OSL) signal of single-grain quartz from three sites in China, Italy, and Libya, including the brightness, decay curve and dose response curve (DRC) shapes, recuperation, and reproducibility. We demonstrate the large variation in OSL behaviors for individual quartz grains of different samples from different regions, and show that recuperation, sensitivity change, and reproducibility are independent of the brightness and decay curve shape of the OSL signals. The single-grain DRCs can be divided into at least eight groups with different characteristic saturation doses (D0), and a standardized growth curve (SGC) can be established for each of the DRC groups. There is no distinctive difference in the shape of OSL decay curves among different DRC groups, but samples from different regions have a difference in the OSL sensitivities and decay shapes for different groups. Many of the quartz grains have low D0 values (30–50 Gy), and more than 99% of the grains have D0 values of <200 Gy. Our results raise caution against the dating of samples with equivalent dose values higher than 100 Gy, if there are many low-D0 and ‘saturated’ grains.

Guide for interpreting and reporting luminescence dating results

“…While there is still debate over whether the D E components identified by the FMM can reliably be used for age calculation, it can quantify grain dose distributions that are not necessarily linked to ages (Guérin et al, 2015(Guérin et al, , 2017. The FMM is useful for understanding the structure of D E distribution data and for distinguishing grains with differing luminescence properties (e.g., Roberts et al, 2000;Gliganic et al, 2015;Smedley et al, 2019;Hu et al, 2020).…”

Luminescence chronology of fluvial and aeolian deposits from the Emirate of Sharjah, UAE

“…5). Much higher values of ∼200% differences were reported for single-grain measurements by Hu et al (2019Hu et al ( , 2020 and Fu et al (2020), and ∼90% for aliquots by Li et al (2016). Mueller and Preusser (2022) found a spread of 30% for samples from Switzerland.…”

“…Distinctly different DRC shapes have been observed for quartz samples in some (see Li et al, 2016;Hu et al, 2019Hu et al, , 2020Fu et al, 2020), but not all, recent studies (Mueller and Preusser, 2022). Hence, it is essential to assess the characteristic shapes of the obtained DRCs prior to SGC construction.…”

Testing the use of continental standardized growth curves (SGCs) for De estimation on coarse quartz grains from Lake Woods, Northern Australia

“…We chose this function here because it has proved to be flexible and robust for fitting DRCs with different shapes (see Peng and Li, 2017),and then, the 'signal growth ratio' (SGR), defined as the ratio between the L x /T x values at 200 and 50 Gy based on the best-fit DRCs for individual grains, is calculated. 2) The SGRs of all investigated grains were divided into k groups using the finite mixture model (FMM) (Roberts et al, 2000), with a zero overdispersion value (σ b = 0) for each group (i.e., assuming that the sources of error associated with the signal intensity have been adequately taken into account, see details in Hu et al, 2019). To determine the optimal number of rSGC groups, k was increased from 2 to 10.…”