Trace element variations and dating of a Late Pleistocene Tasmanian speleothem
Abstract A calcitic stalagmite from Lynds Cave, a limestone cave near Mole Creek in northern Tasmania, Australia, has been dated and shows continuous deposition at a uniform rate from 15.0 to 11.7 ka B.P. (ionium dates) or 12.6 − 8.8 ka B.P. (radiocarbon dates). The age difference obtained by comparing the two dating methods is highly significant and strongly supports recent work by Bard et al. (1990) on Barbados corals. The speleothem was found to be unsuitable for palaeotemperature estimation by oxygen isotope analysis but the time of deposition is known to have been one rapidly rising temperatures. Trace element composition was determined by neutron activation analysis (NAA) for fifteen samples spaced along the stalagmite core. All elements present in measurable quantities showed significant temporal variation in concentrations which are in part believed to be due to environmental change. A significant positive trend in Mg/Sr content and a negative trend in Br content appear to be temperature related. The halide content is shown to be of terrestrial origin.