Simulating archaeological landscape formation to understand late Holocene population dynamics and mobility in arid Australia

Benjamin Davies, Simon Holdaway, Patricia Fanning


Archaeological interpretation depends on the formation of patterns in the material record, but patterns are not always discernible as the outcomes of a single set of processes. In Australia’s desert regions, interpretations of patterning in late Holocene deposits range from intermittent occupation by bands of hypermobile foragers to growing semi-resident populations of complex hunter-gatherers. In particular, archaeologists have focused on the temporal distribution of radiocarbon dates that show trends and gaps consistent with interpretations of population dynamics, periodicity in occupation, and time-dependent preservation. We constructed an exploratory agent-based model around the concept of the palimpsest to evaluate the ability of the coupled processes of cultural and sedimentary deposition and erosion to form these patterns in a surface record of heat-retainer hearths. Initial results suggest that explanations invoking population dynamics or geomorphic processes have the capacity to produce qualitatively similar outcomes. Models are then reconfigured to evaluate a second proxy: optically-stimulated luminescence dates obtained from hearth stones, in order to evaluate the differential influence of these formational processes on these two proxies. The results of the modelling exercises are discussed in relation to patterning observed in the archaeological landscape at Rutherfords Creek, New South Wales, and are used to argue that the record is consistent with neither intermittent occupation or appreciable population growth, but instead indicates regular visitation by groups performing a fairly consistent set of activities during the period of interest. This study demonstrates the suitability of agent-based models for studying archaeological formation, but also how simulations can be used as both ‘tools to think with’ and as mechanisms for developing tests of theoretical ideas.