Holocene climate change in arid Australia from speleothem and alluvial records

Abstract

New high-resolution MC-ICPMS U/Th ages and C and O isotopic analyses from a Holocene speleothem in arid south-central Australia provide evidence for increased effective precipitation (EP) relative to present at c. 11.5 ka and c. 8-5 ka, peak moisture at 7-6 ka, and onset of an arid climate similar to present by c. 5 ka. δ18O and δ13C time-series data exhibit marked (>+1%) contemporaneous excursions over base-line values of -5.3% and -11.0%, respectively, suggesting pronounced moisture variability during the early middle Holocene 'climatic optimuma'. Optically stimulated luminescence and 14C ages from nearby terraced aggradational alluvial deposits indicate a paucity of large floods in the La..