Modelling the palimpsest: An exploratory agent-based model of surface archaeological deposit formation in a fluvial arid Australian landscape

Abstract

Archaeologists make inferences about past human behaviour based on patterned material residues in various depositional contexts, including existing landsurfaces. These deposits are generated by processes that may obscure patterns at some observational scales while highlighting others, and interpretive differences can arise from a lack of explicit models of deposit formation. Here, an exploratory agent-based model based on the concept of the palimpsest is used to examine the effects of episodic sediment transport on the visibility and preservation of surface archaeological deposits in a fluvial context. Outcomes from the model indicate that the compound influences of preservation and visibility are capable of transforming a static radiocarbon record into one of increasing intensity towards the present, while simultaneously displaying periodic chronological gaps – features that have been used in our Australian study area to argue for demographic change driven by social or environmental factors. To differentiate between interpretations, expectations derived from the model are assessed against a second proxy from the same study area: Optically Stimulated Luminescence dates from hearth stones in surface contexts. Results indicate that patterns in the chronometric proxies from the study area are more consistent with episodic geomorphic change than explanations invoking changes in the local organization of human activity.

Spatio-temporal approaches to archaeological radiocarbon dates

“…For the EUROEVOL case, independent lines of evidence such as the juvenility index of cemetery data have already confirmed the broad trends depicted by the SPDRDs (Downey et al 2014). Ultimately the direction to take is to compare multiple proxies of population change and to make a more explicit definition of biases (Davies et al 2016) and confounding variables (c.f. Kramer-Schadt et al 2013 in species distribution modelling) either to calibrate (as in Downey et al 2014) or to test specific hypotheses of demographic changes.…”

Weaving the Common Threads of Simulation and Formation studies in Archaeology

“…A simulation was produced to explore the effects of episodic erosion and deposition on the distribution of ages in visible surface hearths (Davies et al, 2016). In the simulation (Figure 2), agents move randomly from point to point within a gridded space, constructing hearths at a constant rate per annual time step.…”

El Palimpsesto Como Una Puerta De Acceso a Diferentes Temporalidades: El Caso De Río Las Salinas 2 (Tucumán, Argentina)

“…Por definición, una superficie estable es aquélla que existe por un espacio significativo de tiempo y, por lo tanto, es capaz de contener o representar un agregado de ocupaciones distintas (Davies et al 2015;Dibble et al 2016). Para que esto sea así, la exposición de materiales arqueológicos a determinadas condiciones debe darse durante un lapso prolongado (Borrero 2006;Borrazzo 2006, entre otros).…”

“…Esta perspectiva no apunta a la pérdida y destrucción de la evidencia, sino a la valoración de las propiedades acumulativas y transformadoras del registro arqueológico (por ejemplo Binford 1981;Schiffer 1987;Bailey 1981Bailey , 2008Wandsnider 1998;Barton 2003;Borrero 2014;Barrientos et al 2014;Davies et al 2015). Desde esta mirada, los palimpsestos son concebidos como la consecuencia de procesos que crean, a escalas variables, un patrón espacial en el registro factible de ser identificado e interpretado (Bailey 2007: 209) Nº 55 / 2017 Estudios Atacameños Arqueología y Antropología Surandinas .…”