A wiggle-match date for Polynesian settlement of New Zealand

Dating initial colonisation and environmental impacts by Polynesians in New Zealand is controversial. A key horizon is provided by the Kaharoa Tephra, deposited from a eruption of Mt Tarawera, because just underneath this layer are the first signs of forest clearance which imply human settlement. The authors used a log of celery pine from within Kaharoa deposits to derive a new precise date for the eruption via 'wiggle-matching'--matching the radiocarbon dates of a sequence of samples from the log with the Southern Hemisphere calibration curve. The date obtained was 1314 +/- 12 AD (2 sigma error), and the first environmental impacts and human occupation are argued to have occurred in the previous 60 years, i.e. in the late 13th-early 14th centuries AD. This date is contemporary with earliest settlement dates determined from archaeological sites in the New Zealand archipelago.