Luminescence studies of dunes from North-Eastern Tasmania

Northern Tasmania has a geographically extensive cover of Quaternary aeolian features and although the morphology and stratigraphy of many of these have been studied it is difficult to assign a reliable chronology because of the lack of material suitable for radiocarbon dating. The dunes are primarily composed of quartz and hence are ideally suited for the application of luminescence dating. In this paper a variety of luminescence techniques are applied to samples from the area. Analysis of the multiple aliquot OSL measurements showed that a higher precision could be obtained using the signal from the initial 6 mJ.cm^-2 of the optical stimulation rather than the total light sum. The initial near exponential decay of the OSL signal is highly reproducible from one sub-sample to another, but the later part of the OSL decay curve, which is dominate by retrapping effects, is highly variable. The multiple aliquot OSL results are consistent with single aliquot additive dose results. The luminescence ages show that the Ainslie Linear Dunes were initially deposited by 44 ka. were mobile again at 30 ka and have been subject to reworking within the last 100-200 years. It appears that the Quaternary history of aeolian activity in this area has been more complex than was previously thought.