Luminescence Dating in Fluvial Settings: Overcoming the Challenge of Partial Bleaching

Smedley, Rachel ORCID: 0000-0001-7773-5193 and Skirrow, Grace KA (2019) Luminescence Dating in Fluvial Settings: Overcoming the Challenge of Partial Bleaching. Geography of the Physical Environment. pp. 155-168.

Text
Smedley and Skirrow_Luminescence dating in fluvial settings.pdf - Author Accepted Manuscript
Download (809kB) | Preview

Official URL: http://dx.doi.org/10.1007/978-3-030-23315-0_8

Abstract

Optically stimulated luminescence (OSL) dating is a versatile technique that utilises the two most ubiquitous minerals on Earth (quartz or K-feldspar) for constraining the timing of sediment deposition. It has provided accurate ages in agreement with independent age control in many fluvial settings, but is often characterised by partial bleaching of individual grains. Partial bleaching can occur where sunlight exposure is limited and so only a portion of the grains in the sample was exposed to sunlight prior to burial, especially in sediment-laden, turbulent or deep water columns. OSL analysis on multiple grains can provide accurate ages for partially bleached sediments where the OSL signal intensity is dominated by a single brighter grain, but will overestimate the age where the OSL signal intensity is equally as bright (often typical of K-feldspar) or as dim (sometimes typical of quartz). In such settings, it is important to identify partial bleaching and the minimum dose population, preferably by analysing single grains, and applying the appropriate statistical age model to the dose population obtained for each sample. To determine accurate OSL ages using these age models, it is important to quantify the amount of scatter (or overdispersion) in the well-bleached part of the partially bleached dose distribution, which can vary between sediment samples depending upon the bedrock sources and transport histories of grains. Here, we discuss how the effects of partial bleaching can be easily identified and overcome to determine accurate ages. This discussion will therefore focus entirely on the burial dose determination for OSL dating, rather than the dose-rate, as only the burial doses are impacted by the effects of partial bleaching.

Item Type:	Article
Uncontrolled Keywords:	14 Life Below Water
Depositing User:	Symplectic Admin
Date Deposited:	21 May 2020 09:19
Last Modified:	15 Mar 2024 14:33
DOI:	10.1007/978-3-030-23315-0_8
Related URLs:	Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3079849