THE STRANDED BEACH DUNE SEQUENCE OF SOUTH-EAST SOUTH AUSTRALIA - A TEST OF THERMOLUMINESCENCE DATING, 0-800 KA

The remarkable sequence of stranded beach dunes in south-east South Australia deposited during the past 800 ka has provided us with a rare set of samples for testing thermoluminescence sediment-dating methods. Here we report thermoluminescence ages obtained from quartz separated from the dunes, and compare them with accepted ages for the high sea-levels responsible for the dunes. The independent ages of the dunes were obtained from earlier work by Schwebel which has been extended and refined by modelling the dune formation using sea-level variations derived from the oceanic deltaO-18 record. The work is unusual in extending thermoluminescence dating to an 800 ka sequence with modest geological control of the age. The agreement' between thermoluminescence and geological ages is satisfactory for eight dunes with ages in the range 120-800 ka. Quartz is not usually thought to be useful for thermoluminescence dating in this time span; two factors contribute to our success. The first is that the dose rates are low, about 0.5 Gy ka-1, or one quarter of that typical of sediments. The second is that the thermoluminescence vs. dose response continues to rise monotonically above the saturation region at doses above 300 Gy.