Testing the human factor: radiocarbon dating the first peoples of the South Pacific

Abstract

a b s t r a c tArchaeologists have long debated the origins and mode of dispersal of the immediate predecessors of all Polynesians and many populations in Island Melanesia. Such debates are inextricably linked to a chronological framework provided, in part, by radiocarbon dates. Human remains have the greatest potential for providing answers to many questions pertinent to these debates. Unfortunately, bone is one of the most complicated materials to date reliably because of bone degradation, sample pre-treatment and diet. This is of particular concern in the Pacific where humidity contributes to the rapid decay of bone protein, and a combination of marine, reef, C 4 , C 3 and freshwater foods complicate the interpretation of 14 C determinations. Independent advances in bone pre-treatment, isotope multivariate modelling and radiocarbon calibration techniques provide us, for the first time, with the tools to obtain reliable calibrated ages for Pacific burials. Here we present research that combines these techniques, enabling us to re-evaluate the age of burials from key archaeological sites in the Pacific.

Radiocarbon reservoir effects in human bone collagen from northern Iceland

“…The calibrated age ranges produced via the mixed terrestrial/marine calibration curve presented in this study must therefore be taken as minimum estimates due to the potential for the 14 C ages of these samples to be affected by a FRE that is not detectable via stable isotopic analyses. As previously highlighted, when a FRE is substantial, even a minor inclusion of dietary protein from this C reservoir is sufficient to shift the bone collagen and island lagoons (Spennemann and Head, 1998;Petchey et al, 2011 …”

“…The However, the potential for freshwater protein to also impact upon 14 C ages is now also increasingly recognized (Cook et al, 2001;Bayliss et al, 2004;Fischer et al, 2007;Shishlina et al, 2007;Petchey et al, 2011). To obtain appropriate calendar age ranges for affected samples requires an ability to quantify the proportion of reservoir-affected C in a sample.…”

The 2008-2009 Excavations at the Sac Locality, Reber-Rakival Lapita Site, Watom Island, Papua New Guinea

“…These were calibrated using OxCal v3.10 (Bronk Ramsey 2005). The radiocarbon determinations from all previous excavations have been thoroughly discussed in Anson et al (2005: 16-20, 37-39), and samples from Burials 1 and 3 were redated in 2009 (Petchey et al 2011). A full review of the past and current radiocarbon dates for the overall Reber-Rakival site will be undertaken in a future publication, and only the new dates and their contexts are discussed here.…”

“…The first occupation of the site remains undated, as the previous dates that were thought to be from the first visitations (WK 7370 and ANU 5339, which calibrate to before 2800 BP (Anson et al 2005)) are now within the cultural sequence. Recent redating of existing samples of human bone from Burials 1 and 3 by Petchey et al (2011) produced respective dates of 2800-2730 cal BP (Wk15567a and 15567b) and 2670-2640, 2610-2590, 2510-2350. A detailed reconsideration of the stratigraphic context of these burials is required, using the data presented in the present paper, before these dates can be fully interpreted.…”

Lapita diet and subsistence strategies on Watom Island, Papua New Guinea: New stable isotope evidence from humans and animals

“…However, with the exception of the burial ground on Watom and three cemeteries in Vanuatu (Teouma, Uripiv, and Vao) (Bedford et al, , 2011, most human skeletal remains associated with the Lapita people reflect single interments or scattered bone not associated with intact burials (e.g., Pietrusewsky et al, 1998;Katayama et al, 2007), some of which have been redated and found to postdate the Lapita period (Petchey et al, 2011). Recently, the stable isotope analysis of human skeletal remains has become a popular method to assess prehistoric diet in the Pacific islands (e.g., Leach et al, 2003;Valentin et al, 2006;Field et al, 2009;Jones and Quinn, 2009;Richards et al, 2009;Kinaston et al, 2013a,b,c).…”