Abstract Australian climate and vegetation, known from marine and lacustrine sediments and fossils, varied dramatically throughout the Cenozoic Era, with several warm reversals superimposed on overall drying and cooling. A suite of landforms, including stony deserts, dunefields and playa lakes, formed in response to the advancing aridity but their age generally remained uncertain until fairly recently, owing to a lack of suitable dating methods. Within the last 5 years, the chronology of Late Quaternary fluctuations of lakes, dunes and dust-mantles has been established by luminescence dating methods, and mid-Pleistocene onset of playa conditions in a few closed basins has been estimated using palaeomagnetic reversal chronology. Only recently has it been shown, by cosmogenic isotope dating, that major tracts of arid landforms including the Simpson Desert dunefield, and stony deserts of the Lake Eyre Basin, were formed in early Pleistocene and late Pliocene times, respectively. These landscapes represent a stepwise response to progressive climatic drying and, speculatively, were accompanied by biological adaptations. Recent molecular DNA studies indicate that Australia's arid-adapted species evolved from mesic-adapted ancestors during the Pliocene or earlier, but whether speciation rapidly accompanied the development of stony deserts and other arid geomorphological provinces awaits further studies of arid landscape chronology.

Abstract A new map, the first based on interpretation of satellite imagery, reveals both the complexity of Australia's dunefields and their relationships with topography, climate and substrate. Of the five main sand seas, the Mallee, Strzelecki and Simpson in eastern Australia cover Quaternary sedimentary basins whereas the Great Victoria and Great Sandy dunefields in the west are formed by reworking of valley and piedmont sediments in a non-basinal landscape of low-relief ridge and valley topography. These dunefields cover large areas of the arid zone and semi-arid zone and small areas of dunes in sub-humid areas around the margins of the continent reflecting past expansion of arid climates during glacial stages of the last several glacial cycles. Several areas of low relief stand out as being largely dune-free: the limestone Nullarbor Plain, clay plains of the Georgina Basin and floodplains of rivers in the Carpentaria, Lake Eyre and Murray–Darling drainage basins where sand is rare or not transported by diminished Late Quaternary rivers. The Yilgarn Block of southwestern Australia is also surprisingly free of dunes, possibly as a result of long, deep weathering. Everywhere the history of climate change is evident in dune morphology and distribution, including large areas where the sand dune orientations are markedly divergent from modern sand moving wind directions.