Late Holocene Climate Change And Human Behavioural Variability In The Coastal Wet-Dry Tropics Of Northern Australia: Evidence from a pilot study of oxygen isotopes in marine bivalve shells from archaeological sites

Abstract

Previously it has been argued that midden analysis from three geographically distinct coastal regions of tropical northern Australia (Hope Inlet, Blyth River, Blue Mud Bay) demonstrates that changes through time in Aboriginal mollusc exploitation reflect broader coastal environmental transformations associated with late Holocene climatic variability (Bourke et al. 2007). It was suggested that, while a direct link between environmental change and significant cultural change in the archaeological record has yet to be demonstrated unambiguously, midden analysis has the potential to provide the as-yet missing link between changes in climate, environment and human responses over past millennia. We test this hypothesis with a preliminary sclerochronological analysis (i.e. of sequential stable isotopes of oxygen) of archaeological shell samples from all three regions. Our findings suggest the existence of variations in temperature and rainfall indicative of an increasing trend to aridity from 2000 to 500 cal. BP, consistent with previous palaeoenvironmental work across northern Australia.

Sclerochronological analysis of archaeological mollusc assemblages: methods, applications and future prospects

“…Specifically, studies that collect samples at arbitrary distributions (usually 0.5-2 mm) are of the greatest concern (e.g. Aguirre et al 1998;Bailey et al 1983;Brockwell et al 2013;Culleton et al 2009;Voorhies 1995, 1996). Arbitrarily spaced sampling can facilitate the latent mixing of seasonally derived growth features within individual samples, potentially introducing inaccuracies which may significantly alter interpretations.…”

“…While robust sampling strategies and careful selection of proxies can assist in minimising the effects of these issues, the literature indicates that many studies are unsuccessful in incorporating such measures (e.g. Brockwell et al 2013;Kennett and Voorhies 1996;Lightfoot and Cerrato 1988;Stephens et al 2008). Thus, many datasets are potentially poorly calibrated or do not operate at the resolution required for meaningful interpretation.…”

“…Brockwell et al 2013;Burchell et al 2013c;Hallmann et al 2013;Hiscock 1999;Nunn 2003;Rowland 1999;Sim and Wallis 2008). Gaining increased understandings of the environments with which past populations engaged is therefore an integral first step towards more accurate interpretations of human behaviour.…”

“…Yet, many archaeological studies instead rely upon regionally scaled or geographically removed environmental reconstructions (e.g. Brockwell et al 2013;Stephens et al 2008), potentially subjecting associated interpretations to latent biases and inaccuracies.…”

Journeys into the Rainforest (Terra Australis 43)

“…The theme of exploring human-environment interactions and cultural change in response to environmental variability in the Holocene period has also been a focus of more recent research (e.g. Bourke et al 2007;Brockwell et al 2013;Haberle and David 2004). To further resolve the relative importance of climatic, environmental, and cultural changes on human activity and the archaeological record, highresolution palaeoenvironmental sequences, studied in association with fine-resolution archaeological sequences, are clearly required.…”