New perspectives on the Australian deserts

Recent research on the evolution of Australian desert landforms is reviewed, beginning with the macro-landscapes of Western Australia which have changed little for 200 million years, and the desert river courses of that State which have not been active for about 14 million years. Inland Australia in the early Tertiary was characterized by a near-planar landscape subjected to weathering in a hot, very humid climate, resulting in silcrete duricrust development and subsequent lateritization. Late Oligocene diastrophism warped the landsurface into the structural topographic units of today, including the Lake Eyre Basin, and fractured the duricrust which survived as cappings to relict plateaux and mesas. Lateritization ceased in mid-Miocene c. 14 million years ago, and the late Miocene and Pliocene experienced progressive desiccation. The present desert dunefields formed in the late Pleistocene c. 17 000 years ago. The desert has undergone little change over the last 10 000 years, apart from a minor mid-Holocene phase of relative humidity.