Paper I – Optically stimulated luminescence (OSL) dating of perennially frozen deposits in north-central Siberia: OSL characteristics of quartz grains and methodological considerations regarding their suitability for dating

摘要

Optically stimulated luminescence (OSL) dating of coarse-grained quartz is increasingly being used as the main chronological tool in late Quaternary palaeoenvironmental reconstructions of Siberia. However, relatively little information has been published on the suitability of OSL dating for the various types of perennially frozen sediments found in this region. Here we provide a systematic examination of the quartz luminescence characteristics of 21 perennially frozen samples fromthe Taimyr Peninsula and adjacent coastal lowlands of north-central Siberia, and discuss their implications for the reliability of single-grain and multi-grain OSL chronologies in such contexts. The results of this study suggest that the quartz luminescence characteristics of these samples are, in principle, favourable for OSL dating but, in practice, require that a series of validation checks are made of the chosen experimental conditions. If these tests are satisfied, then reliable OSL chronologies should be obtained for sedimentary deposits in this region. Importantly, however, the single-grain and multi-grain aliquot equivalent dose (De) distribution characteristics for our samples reveal that there are advantages in targeting certain types of depositional settings for OSL dating studies of Siberian sediments.We also show that samples from the same depositional settings, and even from the same sites, do not necessarily display similar De distribution characteristics. The latter complication favours the use of single-grain analysis to unravel the bleaching and burial histories of young (mid- to late Holocene) sediments in these Arctic environments.