Abstract
There are two major problems commonly encountered when applying Optically Stimulated Luminescence (OSL) dating in the high dose range: (i) age discrepancy between different grain sizes, and (ii) age underestimation. A marked and systematic discrepancy between fine-grain (4–11 μm) and coarse-grain (63–90 μm) quartz single aliquot regeneration protocol (SAR) ages has been reported previously for Romanian and Serbian loess >40 ka (De of ∼100 Gy), generally with fine-grain ages underestimating the depositional age. In this paper, we show a similar age pattern for two grain size fractions from Chinese loess, thus pointing to a potential worldwide phenomenon. While age underestimation is often attributed to signal saturation problems, this is not the case for fine grain material, which saturates at higher doses than coarse grains, yet begins to underestimate true ages earlier. Here we examine the dose response curves of quartz from different sedimentary contexts around the world, using a range of grain sizes (diameters of 4–11 μm, 11–30 μm, 35–50 μm, 63–90 μm, 90–125 μm, 125–180 μm, and 180–250 μm). All dose response curves can be adequately described by a sum of two saturating exponential functions, whose saturation characteristics (D0 values) are clearly anticorrelated with grain diameter (φ) through an inverse square root relationship, D0 = A/√φ, where A is a scaling factor. While the mechanism behind this grain-size dependency of saturation characteristics still needs to be understood, our results show that the observation of an extended SAR laboratory dose response curve does not necessarily enable high doses to be recorded accurately, or provide a corresponding extended age range.
Original language | English |
---|---|
Pages (from-to) | 464-471 |
Number of pages | 8 |
Journal | Radiation Measurements |
Volume | 106 |
DOIs | |
State | Published - Nov 2017 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2017 The Authors
Funding
B. Guralnik was supported by the Netherlands Organisation for Scientific Research (NWO) VENI grant No 863.15.026. B. Guralnik was supported by the Netherlands Organisation for Scientific Research (NWO) VENI grant No 863.15.026 . A. Timar-Gabor, D. Constantin, V. Anechitei-Deacu have received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme ERC-2015-STG (grant agreement No [ 678106 ]). J-P. Buylaert has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme ERC-2014-STG (grant agreement No [ 639904 ]).
Funders | Funder number |
---|---|
European Union's Horizon 2020 research and innovation programme ERC-2014-STG | |
European Union's Horizon 2020 research and innovation programme ERC-2015-STG | |
VENI | |
Horizon 2020 Framework Programme | 678106, 639904 |
European Commission | |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek | 863.15.026 |
Keywords
- Dose response
- Grain size
- OSL
- Quartz
- SAR
- Saturation characteristics