Wetting and drying of Australia over the past 300 ka

Abstract

Alternately dry and wet climatic episodes across central and eastern Australia during the past 300 ka have greatly affected Australia9s rivers, lakes, and dune fields. Evidence of widespread climate and flow-regime changes has been provided by 75 thermoluminescence (TL) dates and 18 U/Th dates from alluvial and eolian sediments. Fluvial conditions dominated part of the last two interglacials (stage 5 and 7), resulting in large sand loads in rivers in the present Simpson Desert and southeastern Australia. During the last interglacial, fluvial activity in central Australia peaked at ∼110 ka (stage 5 pluvial), probably ∼5-10 ka behind world temperature and sea-level maxima. Following the last late interglacial wet phase, aridity associated with dune building spread from central Australia toward its margins, achieving greatest intensity during the last glacial maximum. A less widespread wet phase, identified at about 55-35 ka (stage 3 subpluvial), is associated with high lake levels and paleochannel activity in southeastern Australia. This TL record of variable continental aridity in Australia correlates well with global changes, including the variable eolian dust flux into central China, the northern Pacific Ocean, and Antarctica.