Abstract: The coastal plains of northern Australia are relatively recent formations that have undergone dynamic evolution through the mid to late Holocene. The development and use of these landscapes across the Northern Territory have been widely investigated by both archaeologists and geomorphologists. Over the past 15 years, a number of research and consultancy projects have focused on the archaeology of these coastal plains, from the Reynolds River in the west to the southern coast of the Gulf of Carpentaria in the east. More than 300 radiocarbon dates are now available and these have enabled us to provide a more detailed interpretation of the pattern of human settlement. In addition to this growing body of evidence, new palaeoclimatic data that is relevant to these northern Australian contexts is becoming available. This paper provides a synthesis of the archaeological evidence, integrates it within the available palaeo-environmental frameworks and characterises the cultural chronology of human settlement of the Northern Territory coastal plains over the past 10 000 years.
As pointed out recently by Ulm (2006:5), 'establishing secure regional chronologies remains a fundamental key to building meaningful accounts on intra- and inter-regional sequences in Australia'. This paper reports a comprehensive summary of radiocarbon dates from early to late Holocene Aboriginal coastal sites in the Northern Territory. It includes both new and previously reported dates from the Reynolds River in the west to the southern coast of the Gulf of Carpentaria in the east. More than 300 radiocarbon dates are now available and these enable more comprehensive comparisons of human settlement and resource use on the coastal plains of the Top End, including identification of phases of cultural change within these landscapes that broadly correlate with environmental and climatic phases.
Coastal site types that have been dated include shell mounds, shell middens, earth mounds, artefact scatters, rock-shelters, and Macassan, European and Chinese contact sites. Here we differentiate between shell middens and shell mounds based on their morphology. Shell middens conform to low, horizontally spread shell deposits over or just below the ground surface (Bourke 2000), whereas shell mounds are larger shell deposits greater than 30 centimetres in height, often occurring as conical or steep-sided ridges (Bourke 2000:60, Hiscock 2008:175-6). The site types identified above are located in five broadly defined regions (Figure 1, Table 1)--the west coast (Reynolds River); the Darwin region (Darwin Harbour, Hope Inlet, Adelaide and Mary Rivers); western Arnhem Land (Alligator Rivers, Magela Creek, Coburg Peninsula); central Arnhem Land (Blyth River, Milingimbi); and eastern Arnhem Land (Cape Arnhem, Port Bradshaw, Blue Mud Bay, Groote Eylandt, Sir Edward Pellew Island Group).
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Geomorphic evidence demonstrates that the north Australian coastal plains on which many of these sites are located are relatively recent formations, which have undergone dynamic evolutionary processes over the mid to late Holocene period. The evolutionary sequence of the coastal plains was similar right across the Territory, with variability related to regional topography and the timing of landscape change (Woodroffe 1995:80). Coastal progradation of this Top End low-energy coast is ongoing today in the context of a climate characterised by two major and clearly delineated seasons--an extended seven-month dry season from May to November, and a wet season from December to April featuring severe storms and cyclones that impact upon the coast.
Holocene evolution of the coastal plains
During the post-Pleistocene transgression, prior coastlines were flooded. Former peninsulas became islands; for example, Groote Eylandt and Vanderlin Island in the Sir Edward Pellew Island Group in the Gulf of Carpentaria were cut off from the mainland about 7000 years BP (Prebble et al. …