Challenging typology: Re-evaluating historical and prehistoric exchanges of Polynesian adzes and pounders with pXRF

Abstract

Collecting artefacts for Western museums was central to the beginnings of archaeological practice in the Pacific. As part of the Collective Biography of Archaeology in the Pacific - A Hidden History (CBAP) ARC Laureate project, this PhD contributes towards an understanding of the history of Polynesian archaeology by re-visiting early museum collections (pre-1960). This research is a process of uncovering Polynesian agency that uses current archaeological methods and knowledge to re-evaluate and re-examine museum objects collected more than half a century ago. Basalt adze typology was one of the first methods Pacific archaeologists developed to investigate the initial human migrations into Polynesia - one of the last regions of the world to be occupied by humans. Over the decades, numerous flaws and shortcomings were highlighted in using adze typology to determine initial migration routes - not least because the adzes used in many of these studies were surface collected and lacked any chronological control. The main issue however, is that Polynesian adze typology was a tool for colonial archaeology, which implied that Polynesian societies were static. Yet adze typology was retained for ease of description and to group the different adze varieties by shape. More recently, following the development of geochemical provenance techniques, Polynesian adzes have been the focus of exchange studies in archaeology. The ability to source basalt adzes found in one location back to a source at a different location, sometimes an island thousands of kilometres away, allows archaeologists to infer past social networks, which can contribute to our understanding of the non-static prehistoric economic and socio-political structures in Polynesia. Polynesian stone pounders are an object-class less studied by archaeologists, but they were nonetheless collected alongside adzes and are now common within museum collections. Pounders are also crafted from basalt but are considered a much more recent invention and thus provide evidence that Polynesians were not a static culture. Stone pounders likely replaced wooden ones sometime in late prehistory and the tradition persisted into the historical period (post Western contact). To date very few decorated basalt pounders have been found in excavated contexts. Pounders have been included in this research to compare and contrast with the adzes, which are often assumed to be prehistoric. Stone pounders were and are still used in everyday contexts for preparing food, pigments and medicine. In the past, some stone pounders crafted by specialists were valuables that served functions in social networks. In order to source basalt objects to their geological origin, this research has employed non-destructive portable energy dispersive X-ray fluorescence (pXRF) elemental data with a new proxy method, the Pearce W-F diagram, for determining volcanic rock type, in combination with multivariate statistics - discriminant function analysis (DFA) in JMPTM. This method for distinguishing basalts from different islands in the Pacific presents a viable alternative to the destructive sampling of basalt objects to obtain major element concentrations. The pXRF technique is thus enhanced for the sourcing analysis of archaeological artefacts and museum objects. Overall, the results from sourcing adzes and pounders reveal that different types of exchanges occurred in Polynesia over time and that the Western colonisation of the region had measurable impacts on these exchange practices. Identifying exchanged adzes in these museum assemblages has implications for the original archaeological interpretations and for the typological distribution of adzes in Polynesia. The analysis of adzes and pounders recovered from the Pandora shipwreck demonstrates how an assemblage-based archaeological approach to museum collections can reveal the plurality of past exchanges in a dynamic Polynesian society.