THE PB-210 CHRONOLOGY OF LATE HOLOCENE DEPOSITION IN AN EASTERN AUSTRALIAN LAKE BASIN

We report here the results of detailed (210)pb analysis of a sequence of lake sediments from Little Llangothlin Lagoon on the New England Tablelands of New South Wales, Australia. (210)pb dating has been rarely employed in Australia and prior to this work no attempt had been made to evaluate the method using independent dating techniques. The chronology of deposition in the lake has been modelled using the Constant Initial Concentration (CIC) and Constant Rate of Supply (CRS) methods. Changes in the palynology and geochemistry of the sediments can be closely matched with well-documented historic events in the lake catchment. The dates of these events have been used to assess the modelled chronologies. Within the limits of resolution of the sampling interval, there is good agreement between the chronology modelled using the CRS approach and the dates inferred for geochemical and palynological events in the sequence. The CIC method provides a less successful match with the historical record, although the differences between the dates derived by the two models are small.