Tuesday, August 26, 2014

Was Vanuatu Settled 3,000 Years ago?

Radiocarbon dating of burials from the Teouma Lapita cemetery, Efate, Vanuatu


Petchey et al


The discovery of a cemetery at Teouma on the island of Efate in Vanuatu dated to c. 3000 years ago increased the number of early Pacific human remains available for study by nearly an order of magnitude and provided for the first time the ability to study the population dynamics of these early colonizers. The cemetery also provided an opportunity to investigate the chronological development of such a unique site. Although identified short-lived plant materials are favoured for dating archaeological sites, the reality of research in the Pacific region is that such materials are often rare, difficult to identify to species because of an absence of suitable reference collections, and dates on other materials often have greater potential to refine and focus 14C chronologies that deal with specific research questions. At Teouma, dates on the burial remains themselves are the best means to answer questions about the age and duration of the burial ground. Human bone, however, is one of the most complicated materials to date reliably because of dietary 14C offsets and bone preservation. One commonly used methodology for calibrating dates on human bone from Pacific human skeletal remains, based on linear interpolation between δ13C endpoints and δ15N values, is complicated by the wide range of foods available (marine, reef, C4 and C3), and remains largely untested in Pacific contexts. Radiocarbon dating of the Teouma site, including 36 Lapita-age burials, 5 dates on Conus sp. ring artefacts, and dates from the associated midden deposit, has enabled further evaluation of 14C dietary offsets and the reliability of calibrated radiocarbon ages on human bone. Bayesian evaluation of the 14C dates suggests the burial ground was in regular use by c. 2940–2880 cal BP, with the last interments occurring c. 2770–2710 cal BP. A number of burials could indicate possible earlier use, perhaps as early as 3110–2930 cal BP as indicated by the calibrated age range of Burial 57. This cannot be independently substantiated using other radiocarbon dates or context at the present time. Overall, these results suggest the burial ground was in use over a possible 150–240 years during the formative phase of Lapita expansion into Remote Oceania.

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