Accurate-parametric SAR-TL dating protocols for older sediments using quartz

Abstract

Thermoluminescence (TL) dating is one of the most significant chronological tools used in Quaternary research. However, for changes in the characteristics of quartz, the larger deviation is still a problem in TL dating, especially with the single-aliquot regeneration-does (SAR) procedure. In the SAR-TL protocol, changes in the characteristics of quartz inevitably cause a shift in the TL peak position and a reduction in the sensitivity of the TL peak during repetitive thermal treatment. In this paper, we studied the optimal TL parameters to minimize the effect of the above problems for TL dating. Based on the optimization experiment combining OSL and TL measurements, the optimal preheat temperature was found to be 300 °C for both silt-sized grains and sand-sized grains, which eliminates the remainder of the 325 °C TL signals and inhibits the 375 °C TL peak position shift. Referring to the test does in SAR-OSL dating protocol, the optimal test doses, 200 Gy and 250 Gy for the silt-sized grains and sand-sized grains respectively, were determined to correct the reduction in TL sensitivity, and they were added to improve the SAR-TL protocol. The improved SAR-TL protocol with the optimal measurement parameters, which we called the accurate-parametric SAR-TL protocol, improves the accuracy of quartz TL dating and expands the range of accurate TL dating. For the experimental doses of 400 Gy and 700 Gy, the relative error of De obtained by the accurate-parametric SAR-TL protocol was less than ±5.5% for both silt-sized grains and sand-sized grains. In addition, we discussed the application conditions of the accurate-parametric SAR-TL protocol and the method that obtains the same level of thermal lag for different luminescence measurement equipment.