Using post-IR IRSL and OSL to date young (≺ 200 yrs) dryland aeolian dunedeposits
Determining the most appropriate luminescence protocol, coupled with suitable data processing methods, for dating recently deposited sediments (<200 years) is important for identifying episodes of sediment movement and interpreting historical landscape dynamics. Issues of partial bleaching, d...
| Main Authors: | , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
Elsevier
2019
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| Summary: | Determining the most appropriate luminescence protocol, coupled with suitable data processing methods, for dating recently deposited sediments (<200 years) is important for identifying episodes of sediment movement and interpreting historical landscape dynamics. Issues of partial bleaching, dim luminescence signals and the incorrect application of rejection criteria, can lead to inaccurate and imprecise ages of recent sediment deposition. This study first compares the performance of quartz optically stimulated luminescence (OSL) and K-feldspar post-IR IRSL (pIRIR) measurements in a series of dose recovery preheat plateau, bleachability and remnant dose tests. Sediments of known historical age are used to identify the most suitable aliquot size and age model choice for further application on near-surface aeolian dune sediments from the Nebraska Sandhills. Results show that the ideal conditions for measuring these aeolian sediments are small aliquots (2 mm) of either quartz or K-feldspar coupled with the relevant protocols (OSL130 pIRIR170) and the unlogged-CAM and unlogged-MAM respectively. Results of 4 ± 7 years (quartz) and 4 ± 8 years (K-feldspar) are in excellent agreement with aeolian sediments of known age 5–6 years. Additionally, we find a revised set of rejection criteria is useful for accurately identifying the appropriate aliquots or grains for reliable age estimation. Sensitivity testing of recuperation rejection criteria highlights the caution that should be taken to avoid arbitrarily applying rejection criteria and biasing towards age overestimations. |
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