Deltaic and estuarine environments and their Late Quaternary dynamics on the Sunda and Sahul shelves

Deltaic and estuarine environments have been, and continue to be, some of the most rapidly changing environments. Those associated with the Sunda shelf generally receive large volumes of sediment and were characterised by a diverse and productive vegetation before much of it was cleared and converted for agriculture, silviculture or urban development. By contrast estuaries in northern Australia receive far less sediment supply, and record a much less modified pattern of landform change during the Holocene. Three periods of change are discussed: first, the long-term geological development and response of deltaic-estuarine plains to eustatic cycles of sea-level change, particularly postglacial sea-level rise to present; second, Holocene development of deltaic-estuarine environments, dominated by patterns of coastal progradation and distributary migration, under relatively stable sea level; and third, the impact of human modifications. These observations provide a framework within which response of the deltaic-estuarine environments to future, anticipated environmental change can be assessed. (C) 2000 Elsevier Science Ltd. All rights reserved.