Duff's adze typology versus Polynesian adze exchanges

The inter-archipelago exchange of adzes after colonisation was not considered in the widely referred to culture historical Polynesian adze typology developed by New Zealand archaeologist, Roger Duff. This portable x-ray fluorescence (pXRF) geochemical study re-examined the assemblage of the adzes in museum collections that were classified into Duff Types by archaeologists Gonzalo Figueroa and Eduardo Sanchez. This paper investigates the geochemical patterning of the Polynesian basalt adze types found on the Pitcairn and Gambier Islands by (1) identifying volcanic rock type of the artefact (2) matching the geological sources used to make the artefacts using a Discriminant Function Analysis (DFA) and, (3) comparing an artefact's identified source to its recorded find spot. The results of the analyses conducted in this paper identified that 16 (8%) adzes had originated from different island groups than where they were collected from in the twentieth century. These adze exchanges provide more evidence of long-distance Polynesian connections that occurred after people initially colonised central east Polynesia and thus further refutes the idea that these islands were occupied in isolation – a critical re-evaluation of Duff's typology is therefore required.