Late Holocene climate change an d 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

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.