Are feldspar SAR protocols appropriate for post-IR IRSL dating?

• The validity of using a SAR protocol for post-IR IRSL dating is tested.
• SAR protocol is appropriate for high temperature post-IR signals (>100 °C).
• IR signals <100 °C may show sensitivity change between natural and first test dose.
• Trapping probability change during first preheat can cause underestimation of De.
• Preheats >260 °C should not be combined with IR stimulation <100 °C.

Recently proposed post-infrared infrared stimulated luminescence (post-IR IRSL or pIR) dating protocols have largely overcome problems associated with anomalous fading and have become increasingly important for age determination of Quaternary sediments. Here, we investigate the suitability of the proposed post-IR IRSL protocols for accurate equivalent-dose estimation on K-feldspar extracts. Our research focuses on potential sensitivity changes between the natural signal and the first test dose signal in single-aliquot regenerative dose (SAR) procedures that are not detected and thus not corrected using test-dose responses.For these investigations, we employed the Single Aliquot Regeneration and Added dose (SARA) procedure, which combines equivalent-dose estimation with a dose recovery test. Results indicated that high-temperature preheats (>260 °C for 60 s) may induce a trapping sensitivity change in IRSL signals measured at low temperature (<100 °C). As this sensitivity change cannot be detected through test dose responses in the SAR protocol, it may result in an invalid equivalent-dose estimation. However, trapping sensitivity changes were not observed after low temperature preheats (<260 °C for 60 s), nor in pIR signals measured at elevated temperature (>100 °C) after a high temperature preheat. Our results indicate that the SAR protocol is appropriate for equivalent-dose determination using elevated-temperature pIR signals (e.g. pIR at 290 °C or multiple elevated temperature pIR at 250 °C). The SAR protocol may also be appropriate for equivalent-dose determination using low temperature pIR signals, provided that the combination of preheat and measurement temperature is carefully chosen to avoid the unwanted effects of sensitivity change during the first preheat.