Vegetation and Climate Change in Southwestern Australia During the Last Glacial Maximum

Abstract

The nature and duration of the Last Glacial Maximum (LGM) in Australia are poorly understood, with little regional agreement on the timing and direction of LGM climate changes. One reason for this is that Australian Late Pleistocene terrestrial sediments typically are both sparse and inorganic, inhibiting the development of detailed radiocarbon chronologies. To address this problem, we extracted fossil pollen from radiometrically dated stalagmites collected in southwest Western Australia. Our pollen record, supported by 30 U-Th dates, reveals the vegetation response to Late Pleistocene climates between ~34 and 14 ka, through the body of the LGM. Before ~28 ka, sclerophyll forests were more open than today, but at ~28 ka forest cover was essentially eliminated, and treeless conditions were maintained until progressive reforestation at ~17.5 ka. This ~10-ka-long full glacial episode correlates with other mid-high latitude Southern Hemisphere records, suggesting that LGM environmental changes were closely coordinated across the hemisphere.