Geochemistry of Stone Tools Reveals the Crossroads of East Polynesia

ABSTRACT Geochemical studies of basalt quarries, rock sources and stone adzes and their biproducts found at distant habitation sites have increasingly allowed archaeologists to track the direction of island colonisation and post‐settlement interaction and proffer explanations for the development of social complexity in Polynesia. The Tuamotu Archipelago is unrivalled for studying inter‐archipelago transfer of stone tools in East Polynesia, as the islands consist of coral sand and limestone with no local sources of volcanic rock. Indeed, with at least 155 imported stone adzes known from the Tuamotus weighing ∼75 kg—more than any other archipelago in Polynesia—the challenge is to determine artefact origin. Using museum collections, we geochemically analysed 25 basalt adzes and preforms (in addition to 19 analyses from a previous study), to track intra‐and inter‐archipelago transfer of these stone tools. Artefacts analysed by inductively coupled mass spectrometry (ICP‐MS) were demonstrated to have originated from the Hawaiian Islands, some 4000 km distant, Marquesas Islands, Pitcairn Island, Austral Islands, the Society Islands and possibly Sāmoa. As almost all artefacts were from known atolls, but not dated archaeological sites, we used Duff adze types to assign broad temporal control to the assemblage. We acknowledge that the importance of long‐curated museum collections cannot be overstated.