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Are quick equivalent doses realistic? Testing range-finder luminescence dating for water-lain and postglacial flooding sediments in NE Poland

Kalińska Edyta, Alexanderson Helena, Weckwerth Piotr, Piotrowski Jan A., Wysota Wojciech

Acta Geologica Polonica

2025

Vol. 75, no. 1

art. no. e36

Raw sediment samples which are without prior lengthy laboratory preparation can be used to obtain a rough but rapid estimate of the luminescence equivalent dose, and thus of the relative age of the sediment. In this study, we tested this range-finder method on clastic sediments in NE Poland for the first time, with special focus on Pleistocene meltwater sediments generated by highly energetic glacial lake outburst floods, and the post-flooding sediments. Two datasets with known doses from standard measurements were compared to range-finder doses determined from quartz and feldspar in untreated sediments. We found statistically significant correlation between equivalent doses of (1) standard quartz optically stimulated luminescence (OSL) and range-finder feldspar infrared stimulated luminescence (IRSL) at 50 ºC, and (2) standard quartz OSL and range-finder quartz OSL in low-dose samples (<80 Gy). However, these correlations should only be considered as approximate whereby preparing more than three range-finder aliquots has the potential of yielding more accurate results. Correlation between the range-finder quartz OSL and range-finder feldspar IRSL is also significant. The range-finder measurements can be used for approximate dose determination to preliminary assess the sediment age or as a selection tool to avoid incompletely bleached samples. The sedimentary environment and especially sediment reworking and transportation seem to influence these correlations. We consider the sediments studied here to have undergone between one and four reworking stages, and samples with repeated reworking usually represent well-bleached material for luminescence dating.

Testing the Applicability of Quartz and Feldspar for Luminescence Dating of Pleistocene Alluvial Sediments in the Tatra Mountain Foothills, Slovakia

Bejarano-Arias Ingrid, Van Wees Roos M. J., Alexanderson Helena, Janočko Juraj, Perić Zoran M.

Geochronometria

2023

Vol. 50, no. 1

50--80

Luminescence dating is a widely used method in combination with sedimentological analysis for reconstructing the landscape development of the Quaternary period. In this study, quartz and K-feldspar measurements were used to evaluate the luminescence characteristics with the aim of dating the deposits. The sediments were sampled from an abandoned gravel pit in the Biely Váh valley and eight sites in the lower part of the Velická dolina valley, High Tatra Mountains, Slovakia. Optically stimulated luminescence (OSL) showed that quartz had an unstable weak signal, and standard single aliquot regeneration (SAR) dose estimates were unreliable, as were doses from pulsed OSL and differential OSL. Infrared (IR50) and post-IR IR225 stimulation (pIRIR225) signals from K-feldspar grains, on the other hand, gave stronger signals but were, to various extents, influenced by incomplete bleaching, fading and uncertainty due to high (>2D0) doses. We find the uncorrected pIRIR225 ages most reliable, though modern analogues indicate that there may be significant residual from incomplete bleaching for some of the samples. The results of the luminescence analyses, ages and sedimentology are put in the context of landscape dynamics and compared to the known glacial history of the Tatra Mountains.