Abstract
Finding the source or provenance of quartz grains occurring in a specific location allows us to constrain their transport pathway, which is crucial information to solve diverse problems in geosciences and related fields. The optically stimulated luminescence (OSL) sensitivity (light intensity per unit mass per unit radiation dose) has a high capacity for discrimination of quartz sediment grains and represents a promising technique for provenance analysis. In this study, we tested the use of quartz OSL sensitivity (ultraviolet emission) measured under different preheating temperatures and with blue light stimulation at room temperature (~20 °C) for sediment provenance analysis. Quartz OSL sensitivity measured at 20 °C is positively correlated with the sensitivity of an OSL signal measured using procedures (preheat at 190 °C for 10 s, blue stimulation at 125 °C and initial 1 s of light emission) to increase the contribution of the fast OSL component, which has been successfully applied for sediment provenance analysis. The higher OSL signal intensity measured without preheating and with light stimulation at room temperature allows the use of lower given doses, thus reducing measurement time. Additionally, the OSL sensitivity measured at 20 °C in polymineral silt samples of a marine sediment core is also suitable for provenance analysis, as demonstrated by comparison with other independent proxies. OSL signals obtained through light stimulation at room temperature have thus the potential to considerably expand measurement possibilities, including in situ measurements using portable OSL readers.
Highlights
Mineral grains resting on or near Earth’s surface can be dispersed through multiple ways, such as by landslides induced by earthquakes [1] or extreme rainfall events [2], winds [3], rivers [4], coastal waves, or tidal currents [5], soil-living insects [6], and diverse human activities [7]
Our experiments show that quartz optically stimulated luminescence (OSL) sensitivity measured without preheating and with optical stimulation at room temperature (~20 ◦C) can be used for provenance analysis in the same way as the OSL measured with preheating and light stimulation at 125 ◦C [21,22,23,28]
When quartz OSL is measured by using preheat (160–260 °C), blue stimulation at 125 °C, and light detection in the ultraviolet band, the initial 1 s of light emission is presumably dominated by the fast OSL component [26], which was intensely characterized for dating purposes [25,35]
Summary
Mineral grains resting on or near Earth’s surface can be dispersed through multiple ways, such as by landslides induced by earthquakes [1] or extreme rainfall events [2], winds [3], rivers [4], coastal waves, or tidal currents [5], soil-living insects [6], and diverse human activities [7]. Despite the fact that the increase of quartz OSL sensitivity due to bleaching–irradiation cycles is well demonstrated by laboratory experiments, e.g., [19,22], it is not conclusive if the sensitization is related with changes in the concentration of charge traps, recombination processes, or both [14,20] This condition does not hinder the use of quartz OSL sensitivity for sediment provenance analysis, e.g., [21]. Our experiments show that quartz OSL sensitivity measured without preheating and with optical stimulation at room temperature (~20 ◦C) can be used for provenance analysis in the same way as the OSL measured with preheating and light stimulation at 125 ◦C [21,22,23,28] This expands the measurements conditions of quartz OSL sensitivity to in situ measurements in sediment cores and outcrop sedimentary successions, as well as in thermally sensitive materials hosting quartz
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