Direct and indirect luminescence dating of tephra: A review

Abstract

In Quaternary studies, tephras are widely used as marker horizons to correlate geological deposits. Therefore, accurate and precise dating is crucial. Among radiometric dating techniques, luminescence dating has the potential to date tephra directly using glass shards, volcanic minerals that formed during the eruption or mineral fragments that originate from the shattered country rock. Moreover, sediments that frame the tephra can be dated to attain an indirect age bracket. A review of numerous luminescence dating studies highlights the method's potential and challenges. While reliable direct dating of volcanic quartz and feldspar as a component in tephra is still methodically difficult mainly due to thermal and athermal signal instability, red thermoluminescence of volcanic quartz and the far-red emission of volcanic feldspar have been used successfully. Furthermore, the dating of xenolithic quartz within tephra shows great potential. Numerous studies date tephra successfully indirectly. Dating surrounding sediments is generally straightforward as long as samples are not taken too close to the tephra horizons. Here, issues arise from the occurrence of glass shards within the sediments or unreliable determination of dose rates. This includes relocation of radioelements, mixing of tephra into the sediment and disregarding different dose rates of adjacent material.

Chronological Assessment of the Balta Alba Kurgan Loess-Paleosol Section (Romania) – A Comparative Study on Different Dating Methods for a Robust and Precise Age Model

“…Dating tephra deposits using luminescence techniques is not always straightforward, even when the surrounding sediments are dated (cf. Bösken and Schmidt, 2020). Independent of the dated grain-size range, samples taken in close proximity to the tephra layer are particularly critical, since fresh geologic deposits are prone to relocation of radioelements leading to an incorrect ascertainment of dose rates (Krbetschek et al, 1994;Biswas et al, 2013;Bösken and Schmidt, 2020).…”

Optically Stimulated Luminescence Phosphors: Principles, Applications, and Prospects

“…The increased utilization of OSL‐based luminescence dating presents its capacity to date events beyond other methods and enables chronological frameworks to be established. [ 24,292–329 ]…”

Crossing new frontiers: extending tephrochronology as a global geoscientific research tool

“…Bösken and Schmidt (2020) provide a useful review of the dating of tephras using luminescence methods. Using tephras as isochronous age markers relies on the dating of at least one occurrence of the tephra that can then be transferred between sites, and luminescence dating is one technique that can be utilised for this.…”

“…It is a versatile but complex technique because different methods can be used to both directly date tephras using glass shards, volcanic minerals and/or country rock, or provide indirect age brackets through the dating of sediments encapsulating tephras. Bösken and Schmidt (2020) review past studies of both direct and indirect dating approaches, highlighting the potential demonstrated by the different methods and challenges encountered, before providing key recommendations for future studies.…”