Late Pleistocene palaeotemperature record from a Tasmanian speleothem

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Abstract
Multiple 230Th/234U age determinations on a uniform diameter calcite stalagmite from a Tasmanian cave show that it was deposited between 109 000 and 76 000 years BP at a constant rate of 4.3 cm per 100 years. Except for the first 9000 years, deposition occurred under conditions of oxygen isotope equilibrium enabling it to be used for palaeotemperature studies. Measurements of 18O/16O ratios of calcite and d/h ratios of fluid inclusions indicate that mean annual temperatures at the site were nearly always lower than at present from 100 000 to 76 000 BP. A positive relationship is found between mean annual temperature and the 18O/16O content of calcite. This is uncommon and represents the first such relationship recorded from the Southern Hemisphere. The stalagmite shows evidence of having grown during two distinct temperature phases. From 100 000 to 97 000 years BP mean annual temperatures were between 4°C and 6°C compared with a present day value of 9.5°C. At about 97 000 years BP there was a rapid transition to milder conditions with mean annual temperatures oscillating around 8°C until the record terminates at 76 000 years BP.