Obsidian and volcanic glass artifact evidence for long-distance voyaging to the Polynesian Outlier island of Tikopia

Reconstructing routes of ancient long-distance voyaging, long a topic of speculation, has become possible thanks to advances in the geochemical sourcing of archaeological artifacts. Of particular interest are islands classified as Polynesian Outliers, where people speak Polynesian languages and have distinctly Polynesian cultural traits, but are located within the Melanesian or Micronesian cultural areas. While the classification of these groups as Polynesian is not in dispute, the material evidence for the movement between Polynesia and the Polynesian Outliers is exceedingly rare, unconfirmed, and in most cases, nonexistent. We report on the first comprehensive sourcing (using a portable X-ray fluorescence spectrometer) of obsidian and volcanic glass artifacts recovered from excavations on the Polynesian Outlier island of Tikopia. We find evidence for: (1) initial settlement followed by continued voyages between Tikopia and an island Melanesian homeland; (2) long-distance voyaging becoming much less frequent and continuing to decline; and (3) later voyaging from Polynesia marked by imports of volcanic glass from Tonga beginning at 765 cal yr BP (±54 yr). Later long-distance voyages from Polynesia were surprisingly rare, given the strong cultural and linguistic influences of Polynesia, and we suggest, may indicate that Tikopia was targeted by Tongans for political expansion.