Late quaternary environmental changes in eastern and central Australia, and their climatic interpretation

The march of environmental changes in eastern Australia, from the Last Interglacial to the Holocene, is reviewed. Palynologic evidence suggests that forest composition fluctuated substantially during Oxygen Isotope (OI) Substages 5a to 5e, but physical evidence for this period is as yet poorly defined. During OI Stage 3 and possibly part of 4, inland lakes were larger and the hydrologic balance was wetter than at any time since. Conditions were coldest, and dune activity was maximal throughout the continent, during OI Stage 2, but driest conditions as judged from lake levels occurred at the termination of the Pleistocene, when temperatures were rising rapidly. Lags between changes of boundary conditions and responses of natural systems are clearly seen in Holocene behaviour of coasts and reefs, and the effects of extreme events rather than climatic changes are seen in some sedimentary sequences. Establishment of the chronology of deposits older than about 35 ka, and forging links between the terrestrial and deep-sea records, are major challenges for future research.