Discontinuity in the Fijian Archaeological Record Supported by a Bayesian Radiocarbon Model

Abstract

The Fijian archaeological record is segmented into a series of phases based on distinctive transformations in ceramic forms. Interpretations of the mid-sequence (~1500-1300 cal BP) transition between the Fijian Plainware phase and the Navatu phase are contentious, with alternative explanations of population replacement versus internal processes of culture change. We present and analyze a series of Fijian Plainware and Navatu phase AMS radiocarbon dates acquired from superimposed but stratigraphically separated occupation floors at the Sigatoka Sand Dunes site on the southwest coast of Viti Levu. Employing an OxCal Bayesian sequential model, we seek to date the temporal span for each occupation as well as the interval of time occurring between occupation floors. The latter is estimated to be 0-43 calendar years at 2s probability. The magnitude of ceramic and other differences between the Fijian Plainware and Navatu phase occupations at Sigatoka is substantive. We conclude that the abruptness of this change can be explained only by exogenous replacement at the Sigatoka site.

Bayesian Modeling and Chronological Precision for Polynesian Settlement of Tonga

“…Recent analyses of radiocarbon chronologies in Oceania, whether at the site, island group or regional meta-analysis scale, emphasize and apply Bayesian analysis as a means to identify outlier dates, refine understanding of depositional events or develop chronological models for archaeological sequences [ 7 ], [ 22 ], [ 23 ]. OxCal software for radiocarbon date calibration and analyses considerably facilitates this scholarship.…”

Recent Progress, Trends, and Developments in Island and Coastal Archaeology

“…Because of the voluminous amounts of shell that often occur in coastal sites and the relatively clear association of these materials with human activities, archaeologists working on islands and coastal zones have continued to refine and build on local reservoir corrections for a variety of areas (e.g., Petchey and Clark 2010;Rick et al 2012a;Thomas et al 2013). The refinement of corrections and calibrations for marine samples has also helped fuel the increasing application and use of Bayesian statistics to conduct a wide range of analyses, to help narrow the standard deviation of a particular range of dates, to help determine the presence of outliers, and to conduct other chronological analyses within a statistical framework (see Allen and Morrison 2013;Burley and Edinborough 2014;Kennett et al 2012;Rieth et al 2008). The Bayesian platform provided in Oxcal has been a prime mover of much of this research (see Bronk Ramsey 2009).…”

Radiocarbon test for demographic events in written and oral history

“…First, the calibrated radiocarbon results were examined for visually obvious gaps in Prince Rupert Harbour settlement history that may correspond to the oral historical record. A battery of models using OxCal radiocarbon calibration software (Dataset S2) was used to construct two groups (phases) of dates around the most obvious candidate gap following a well-established research protocol derived from two recent exceptional archaeological cases, sequenced using ideally dated and stratified radiocarbon material from Fiji and Tonga in Polynesia (36,37). Only one OxCal model gave a sufficiently good agreement index that allowed the data to be sequenced into two phases.…”