Measurement of anomalous fading for feldspar IRSL using SAR

Age underestimates and wide equivalent paleodose distributions are commonly observed in IRSL dating of feldspar minerals using both multiple and single aliquot methods. For well-bleached sediments, this is thought to be caused primarily by anomalous fading. This article explains how to assess a fading rate (g value), which can be used to correct the measured optical ages. It also shows how different fading rates are obtained on single-aliquots using different protocols. It is found that the g value deduced from delayed L_i/T_i measurements is strongly dependent on the timing of the preheat treatment. For the single-aliquot regenerative-dose protocol (SAR), best results are obtained using delayed L_i/T_i ratios if the samples are preheated before storage.