Electron spin resonance (ESR) dating of optically quartz grains: a light at the end of the tunnel?

Abstract

Although the first ESR dating attempt of optically bleached quartz grains extracted from Quaternary sediment was published > 30 years ago (Yokoyama et al., 1985), the application remains relatively poorly known and not widely accepted among the community of Quaternary scientists. This situation is contrasting with Luminescence, which has become instead increasingly popular over the last decades, thanks to several major methodological developments leading to significant improvements in terms of accuracy and reliability. In that regard, ESR can probably not compete with Luminescence dating, as there are some intrinsic technical limitations (e.g., impossibility/difficulty to run automated ESR measurements or to perform single grain analyses) that currently limit any major future developments. Additionally, the reduced number of ESR dating specialists around the world working on this application is clearly another limiting factor. That said, there are nevertheless some situations where ESR can be of special interest in Quaternary studies. It can be used to take over Luminescence when this one shows apparent limitations, or provide some useful chronological constraints when no other numerical dating method is available (e.g. Sahnouni et al., 2018; Bartz et al., 2018). In the recent years, some efforts have been dedicated among the ESR dating community to start a standardization of the method (e.g. Duval et al., 2017). Additionally, the increasing systematic use of the multiple centre approach, in combination with cross-comparisons with independent dating methods (e.g., Mendez-Quintas et al., 2018, Bartz et al., 2019; Duval et al., submitted), show that ESR can be a reliable dating tool. The present contribution will give an updated overview of the potential and current limitations of ESR dating method based on some recently published case studies for which semi-independent age control was available.