Circumventing possible inaccuracies of the single aliquot regeneration method for the optical dating of quartz

摘要

A simple method of assessing the reliability of the single aliquot regeneration method is presented, based on the repeated measurement of identical regeneration doses. It is shown that for the majority of the samples measured the requirement of a constant repeal point in each cycle is not met. The ability to maintain a constant repeat point is shown to be dependent upon preheating conditions, the requirements for which were found to vary at both intersample and inter-aliquot levels. The expected effect on estimated values of D-e is calculated and shown to be significant. Three possible means of circumventing these inaccuracies are presented: (i) adjustment of the measurement procedure (specifically the preheat conditions); (ii) modelling and correcting for the effect, and (iii) stabilising the response prior to construction of the regenerated growth curve. It is suggested that much of the variation in D-e observed between individual aliquots and between individual grains from well-bleached sediments may possibly be attributed to differences in preheating requirements, and that such differences may also account for some of the spread in D-e for partially bleached sediments. (C) 2000 Elsevier Science Ltd. All rights reserved. [References: 7]