Progress in luminescence dating of Chinese loess by single-aliquot regenerative-dose (SAR) protocol

Here we reported the improvements in luminescence dating from fine grains of Chinese loess. For isolating fine quartz from polymineral grains in Chinese loess, it is more valuable to use ultrasonic bathing during etching the feldspar by H2SiF6, because of the aggregates of fine grains. IR detection confirmed the purity of OSL signals from fine quartz for luminescence dating purposes. Single-aliquot regenerative-dose (SAR) protocol was used to determine the equivalent dose (DE) for fine quartz OSL, polymineral IRSL and Post-IR OSL in Chinese loess during the last glacial-interglacial. Linear modulation technique was used to identify the characteristic of Post-IR OSL from polymineral grains. It is confirmed that characteristic of Post-IR OSL after long time of IR stimulation is similar to those of fine quartz OSL. In order to obtain reliable DE value from Post-IR OSL of polymineral grains, it is necessary to determine a sufficient IR stimulation time by the plateau test of Post-IR OSL DE v.s. IR stimulation duration, as did for preheating condition in previous luminescence dating. The performance of IRSL and Post-IR OSL in determining the DE value with ranges of 0-300 Gy was also discussed by comparing to fine quartz OSL DE. (authors)