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For each graph, individual ranges (68% probability) of Class 1 calibrated radiocarbon dates are shown as black horizontal lines; circles represent median (bottom axis). The high proportion of unidentified charcoal in Class 3 shows this category of dated materials in the dataset also tends to have large measurement errors. Age estimates for initial colonization of the Gambier archipelago are unusually broad (167-y difference between the EAEM and LAEM, i.e., between A. ∼11) compared with all other islands (average difference of 55 y between earliest and latest estimates). ∼1219–1266, respectively), some 200–500 y later than widely accepted (16, 17), placing them in close agreement with both New Zealand and Rapa Nui.
Red dashed line indicates sum of probability distributions (left axis). 1200 based on the assumption that we have 100% confidence that colonization had occurred by this time; and for the remaining islands with Class 1 dates, this was set to A. The distribution of calibrated age ranges for all classes of radiocarbon dates shows a clear pattern across the entire region (Fig. 1025 to 1520, in contrast to those of Class 2–3 dates, which extend back to 500 B. This pattern reflects the higher precision and accuracy of the reliable targets that make up Class 1 dates (i.e., short-lived materials with SEs and Fig. Using our models, we can show a robust and securely dated two-phase sequence of colonization for East Polynesia: earliest in the Society Islands A. ∼1025–1120, four centuries later than previously assumed, and significantly before (by ∼70–265 y) all but one (Gambier) of the remote island groups with Class 1 dates. This is caused by one date in the Gambier group [Beta-271082: 970 ± 40 BP on carbonized ), leaving initial colonization age ambiguously between that of the central and marginal East Polynesian islands. ∼1200–1253, respectively) but with much larger sets of Class 1 dates. They are also in close agreement with age estimates for initial colonization on the remaining island groups, with Class 1 dates including Line, Southern Cooks, and the sub-Antarctic Auckland Island, which all show remarkably contemporaneous chronologies within radiocarbon dating error (Fig. The unity in timing of human expansion to the most remote islands of East Polynesia (encompassing the triangle made between Hawaii, Rapa Nui, and Auckland Island) is even more extraordinary considering these islands span a vast distance of both longitude and latitude (Fig. Collectively, these results, based on only the most reliable samples, provide a substantially revised pattern of colonization chronology for East Polynesia, which shortens the age for initial colonization in the region by up to 2,000 y, depending on various claims asserted for earlier chronologies (3, 9, 10).
For example, some of the oldest dates for the Auckland Islands are based on small-diameter (2-cm) wood from long-lived trees (), which, despite the size of twigs, may still contain inbuilt age and create an artificial tail to the probability distributions (19).
The narrow age distribution of colonization through remote East Polynesia is not explained as merely a function of analyzing smaller subsets formed by Class 1 dates.
In a meta-analysis of 1,434 radiocarbon dates from the region, reliable short-lived samples reveal that the colonization of East Polynesia occurred in two distinct phases: earliest in the Society Islands A. ∼1025–1120, four centuries later than previously assumed; then after 70–265 y, dispersal continued in one major pulse to all remaining islands A. Our empirically based and dramatically shortened chronology for the colonization of East Polynesia resolves longstanding paradoxes and offers a robust explanation for the remarkable uniformity of East Polynesian culture, human biology, and language.
It is no longer reasonable to argue that evidence of earlier settlements is “missing” or archaeologically invisible through sampling or taphonomic problems [Discussion in (4)], or that particular radiocarbon dates upon specifically unidentified samples, or samples with weak stratigraphic connections to cultural remains make a case for earlier ages of colonization (9, 10).Existing Customers: Sign in for help with placing your order.Sign into My Verizon to get help selecting the right product.This allows radiocarbon dates, irrespective of stratigraphic context, to be categorized according to accuracy and precision, and for patterns of age and distribution of colonization to be sought accordingly upon the most reliable dated materials.Here accuracy is defined based on those samples that can provide a date that is the “true” age of the sample within the statistical limits of the date.To accomplish this, it is necessary to be conservative in evaluating the usefulness of data.That is, to accept only those dates that () are capable of providing a calibration that is close to the “true” age of the actual target event (i.e., human activity).The consistent, contemporaneous nature of East Polynesian age distributions is better explained by extraordinarily rapid migration from the centrally positioned East Polynesian islands in the 13th Century.Migration into eastern Polynesia began after a 1,800-y pause since the first settlement of Samoa, ∼800 B. (12), which implies a relatively sudden onset of whichever environmental or cultural factors were involved.One approach is to evaluate dates within their individual and comparative stratigraphic levels according to criteria of “chronometric hygiene” (11, 12) and build from those results toward a regional overview; but this method can be subjective, and it is impractical when dealing with very large databases, as is the case here.Instead we have chosen a “top-down” approach to evaluate the entire archaeological radiocarbon database for East Polynesia as a single entity.