Single-grain dating of potassium-rich feldspar grains: Towards a global standardised growth curve for the post-IR IRSL signal

Abstract

Potassium-rich feldspar (K-feldspar) grains were extracted from 28 sediment samples from sites in Asia, Europe and Africa and the dose response curves-or growth curves-were constructed from the postinfrared infrared stimulated luminescence (pIRIR) signals emitted by individual grains. The samples exhibit large between-grain variation in both pIRIR signal intensity and the shape of the corresponding growth curves; the latter can be largely explained as a result of measurement uncertainties, including counting statistics and instrumental irreproducibility. This between-grain variation can be reduced by applying a least-squares normalisation (LS-normalisation) procedure, which allows a common growth curve-or global standardised growth curve (gSGC)-to be established for individual K-feldspar grains from the range of samples investigated. Equivalent dose (D e) values for single grains can be estimated using the fitting parameters of the gSGC, together with measurements of the natural signal (L n), one regenerative-dose signal (L x) and their corresponding test-dose signals (T n , T x). The D e values obtained using the gSGC approach are consistent at 2σ with those obtained from the individual growth curves constructed for each of the grains. The establishment of a gSGC greatly reduces the time required to measure a large number of grains for old samples, and it also overcomes the problem of D e underestimation that can occur using a full single-aliquot (or single-grain) regenerative-dose (SAR) procedure when a large number of grains are rejected due to issues of 'saturation'. The construction of a gSGC may, therefore, potentially extend the dating range of pIRIR signals beyond the reliable limit of D e estimation using the standard SAR method.

Establishing a common standardised growth curve for single-aliquot OSL dating of quartz from sediments in the Jilantai area of North China

“…x /T x data and that obtained from the SGC in a radial plot in Fig. 5e and f. There is no systematic dose dependency of the ratios for these two SGC methods, which is consistent with the observations on K-feldspar SGC (Li et al, 2018). In the radial plots in Fig.…”

Review of the Post-IR IRSL Dating Protocols of K-Feldspar

“…Usually, the D 0 would increase when the maximum regenerative dose is larger [107]. When using the same D t , the identical pIRIR signal from K-feldspar has quite similar saturation behavior between different samples [78,102,105]. Individual growth curves of different K-feldspar grains or aliquots from different continents become very close to each other after re-normalization or re-scaling, which indicates the existence of a global SGC of K-feldspar [102,105].…”

“…A least-squares normalization procedure ('LS-normalization') was proposed to establish the SGCs for quartz from Haua Fteah cave, Libya [76]. Later, this LS-normalization procedure has also been applied in constructing SGCs for K-feldspar [92,105]. The 'LS-normalization' can further reduce the inter-grain and inter-aliquot variation of individual growth curves.…”

Methods in Dating and Other Applications using Luminescence

“…A least-squares normalization procedure ('LS-normalization') was proposed to establish the SGCs for quartz from Haua Fteah cave, Libya [76]. Later, this LS-normalization procedure has also been applied in constructing SGCs for K-feldspar [92,105]. The 'LS-normalization' can further reduce the inter-grain and inter-aliquot variation of individual growth curves.…”