A New Major Adze Quarry from Nānākuli, O‘ahu: Implications for Interaction Studies in Hawai‘i

Abstract

A major new basalt adze quarry at Nānākuli Valley, Hawaiian Islands is described which now ranks as one of the two largest on O‘ahu and aside from the Mauna Kea adze quarry complex on Hawai‘i island and the Haleakalā source on Maui, is one of the major quarries in the archipelago. We defined the approximate limits of the quarry complex, located the in situ geological source of the fine-grained basalt used for adze manufacture, report the petrographic and geochemical variability of the source rock, and describe the adze reduction strategies from analysis of adze blanks and
preforms, as well as hammerstones and debitage. The geochemical variation of the nine source rocks and artefacts were defined by a comprehensive array of 10 fully quantitative major element concentrations, 43 trace element abundances, and high-precision Sr-Nd-Pb isotopic ratios obtained using the state-of-the-art Thermal Ionization Mass Spectrometry (TIMS, for Sr isotopes), Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS, for Nd-Pb isotopes), quadrupole ICP-MS (for trace elements) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES, for major elements), respectively. A piece of branch coral was recovered from the surface of a rockshelter that provided a U-series date of possible quarry use in the mid-13th century. It is advocated that a comprehensive range of major and trace element concentrations and Sr-Nd-Pb isotopic ratios are required for geochemically characterising adze quarries to facilitate the long-term viability of sourcing studies.