“The material for boring the greenstone”: characterization and archaeological distribution of the Pahautane chert, West Coast, South Island, New Zealand

Phil Moore; Andrew La Croix

doi:10.70460/jpa.v15i1.383

Authors

Phil Moore Peninsula Research https://orcid.org/0009-0001-2782-091X
Andrew La Croix Sedimentary Environments and Analogues Research Group, Earth & Environmental Sciences, School of Science, University of Waikato, Hamilton 3240, New Zealand https://orcid.org/0000-0002-9716-9501

DOI:

https://doi.org/10.70460/jpa.v15i1.383

Keywords:

chert, Pahautane, petrography, artefacts, South Island

Abstract

The Pahautane chert, which occurs as isolated pockets within Oligocene bioclastic limestone on the West Coast of the South Island, New Zealand, was exploited by indigenous Māori communities over a period of at least 500 years. Thin-section petrography of samples from two localities reveals that the chert is composed predominantly of quartz (85-90% SiO₂) and calcite (10-15% CaCO₃) with common silicified fossil remains, mainly of benthic foraminifera and sponge spicules, but including a variety of other fauna. Wavelength-dispersive XRF analyses indicate a slightly higher silica content (91-95 weight % SiO₂), and very low concentrations of all other elements except calcium. The visually similar Gordon’s Valley chert in South Canterbury, some 260 km to the south, has an almost identical composition.

Examination of artefact collections at Canterbury Museum, and other records, shows the Pahautane chert was more widely dispersed than previously thought, and distributed along the western coast of the South Island over a total distance of at least 300 km. This distribution pattern reflects the use of well-established communication routes for the export of nephrite (pounamu) from the West Coast, probably beginning in the late 13th or early 14th century. On the West Coast, Pahautane chert was being used for drilling holes in nephrite up until the middle 1840s.

Author Biography

Andrew La Croix, Sedimentary Environments and Analogues Research Group, Earth & Environmental Sciences, School of Science, University of Waikato, Hamilton 3240, New Zealand

Senior Lecturer

School of Science

University of waikato

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