Improved methodology and new thermoluminescence ages for the dune sequence in south-east South Australia

Our thermoluminescence dating technique for quartz extracted from late Pleistocene sediments has been improved by the addition of a 33 h 160 degreesC preheat before measurements. This yields better plateaux, which now encompass the region known as the 325 degreesC TL peak; this is consistent with the prediction, from isothermal decay studies, of the lifetime at ambient temperature of the traps responsible for this peak. The preheat does not help resolve problems associated with dose responses above 600 Gy. Some details of the dose response are shown to be better understood with the aid of 3-D TL spectra. The improved method has been applied to one former and seven new samples from the stranded beach-dune sequence in south-east South Australia. The five ages obtained for the main dune sequence range from 95 +/- 6 to 725 +/- 100 ka and all are consistent with the expected ages. (C) 2000 Elsevier Science Ltd. All rights reserved.