An assessment of the luminescence sensitivity of Australian quartz with respect to sediment history

Abstract

Abstract:This study provides a preliminary systematic characterisation of OSL sensitivity, with respect to sediment history, of single grains of Australian quartz from a variety of source rocks and depositional contexts. Samples from two distinct lithologies and with relatively short modern sedimentary histories were compared in an examination of the influence of rock type on OSL sensitivity. Sediments derived from weathered sandstone were found to be brighter than those from metamorphosed schists, suggesting that sensitivity may be inherited from the source rock and its earlier sedimentary history. Secondly, quartz from the same source, but different modes of deposition, was compared to assess the effect on sensitivity of nature of exposure to light during the most recent bleaching event. Quartz grain sensitivity appears not to vary depending on the mode of sediment deposition, suggesting that the nature of exposure to light during deposition is less important in the sensitisation process. This study highlights the complexity and variety of natural sedimentary quartz, demonstrating the limitations of an investigation based solely on OSL sensitivity. Further systematic investigation into the physical, geological and geomorphological characteristics of sediments is proposed to better understand the mechanisms of luminescence sensitisation in quartz.

Multi-method luminescence investigations on quartz grains of different sizes extracted from a loess section in Southeast Romania interbedding the Campanian Ignimbrite ash layer

“…This corresponds to 15% and 14% of the total measured grains. This proportion is consistent with observations from other single grain studies from a range of contexts, from aeolian to fluvial and cave deposits (Jacobs et al, 2006;Fitzsimmons, 2011). However, the majority of sand-sized grains measured from Valea cu Pietre were categorised as dim (yielding <20 counts in the initial channel of the natural signal).…”

“…However, the majority of sand-sized grains measured from Valea cu Pietre were categorised as dim (yielding <20 counts in the initial channel of the natural signal). Aeolian sediments in general have been thought to yield relatively high sensitivities (Fitzsimmons et al, 2010;Fitzsimmons, 2011;Li and Wintle, 1992), as have sediments which have undergone long-distance transport within rivers (Pietsch et al, 2008). Therefore the Romanian loess-forming, sand-sized grains, which are not only assumed to be aeolian but have undergone longdistance fluvial transport (Smalley and Leach, 1978), may reasonably have been assumed to exhibit a high efficiency of charge transfer between traps and luminescence centres.…”

Attaining provenance proxies from OSL and TL sensitivities: Coupling with grain size and heavy minerals data from southern Brazilian coastal sediments

“…Fitzsimmons et al, 2010;Fitzsimmons, 2011;Notenboom, 2013;Pietsch et al, 2008;Preusser et al, 2006;Sawakuchi et al, 2011a, b;Sawakuchi et al, 2012;Westaway, 2009;Lü et al, 2014). These studies evaluate the contribution of source rocks and suggest increases in sensitivity with multiple cycles of burial and light exposure in nature that can be reproduced in laboratory conditions with sequences of irradiation, heating and bleaching.…”

Realizing the potential of fluvial archives using robust OSL chronologies

“…Samples from any environment can show poor sensitivity (e.g. Fitzsimmons, 2011;Lukas et al, 2007), and highly-skewed sensitivity distributions (Duller, 2008). It is not uncommon for 95% of the combined OSL signal to come from less than 5% of the grains.…”