Atoll Archaeology in the Pacific

As islands formed by biogenic agents (unconsolidated carbonate sediments deposited by waves on reef platforms), atolls and table reefs, or low coral islands without lagoons, can be regarded as especially constraining habitats for human settlement. The challenges faced by people, both past and present, include low soil fertility, absence of perennial surface freshwater, and extreme vulnerability to flooding by stormsurge and sea-level rise due to low elevation of the highly fragmented landmass, only a few meters above mean sea level. There are about 300 atolls and low coral islands in the Pacific and thousands of individual islets (motu). Several archipelagoes are dominated by these limestone islands, such as the Tuamotus, the Central and Eastern Carolines, the Marshall Islands, Kiribati, and Tuvalu. Because of their small size, limited and at time fluctuating resources, and relative isolation, atolls are often perceived as marginal environments. While some human communities did not endure (Di Piazza and Pearthree 2001), a remarkable number were sustainable for centuries, taking advantage of opportunities many atolls provided and indicating a long history of resilience to environmental variability (Fitzpatrick et al. 2016). Despite these achievements, atolls have received relatively little coverage by Pacific archaeologist

High Precision U/Th Dating of First Polynesian Settlement

Previous studies document Nukuleka in the Kingdom of Tonga as a founder colony for first settlement of Polynesia by Lapita peoples. A limited number of radiocarbon dates are one line of evidence supporting this claim, but they cannot precisely establish when this event occurred, nor can they afford a detailed chronology for sequent occupation. High precision U/Th dates of Acropora coral files (abraders) from Nukuleka give unprecedented resolution, identifying the founder event by 283868 BP and documenting site development over the ensuing 250 years. The potential for dating error due to post depositional diagenetic alteration of ancient corals at Nukuleka also is addressed through sample preparation protocols and paired dates on spatially separated samples for individual specimens. Acropora coral files are widely distributed in Lapita sites across Oceania. U/Th dating of these artifacts provides unparalleled opportunities for greater precision and insight into the speed and timing of this final chapter in human settlement of the globe

Language trees support the express-train sequence of Austronesian expansion

Languages, like molecules, document evolutionary history. Darwin(1) observed that evolutionary change in languages greatly resembled the processes of biological evolution: inheritance from a common ancestor and convergent evolution operate in both. Despite many suggestions(2-4), few attempts have been made to apply the phylogenetic methods used in biology to linguistic data. Here we report a parsimony analysis of a large language data set. We use this analysis to test competing hypotheses - the "express-train''(5) and the "entangled-bank''(6,7) models - for the colonization of the Pacific by Austronesian-speaking peoples. The parsimony analysis of a matrix of 77 Austronesian languages with 5,185 lexical items produced a single most-parsimonious tree. The express-train model was converted into an ordered geographical character and mapped onto the language tree. We found that the topology of the language tree was highly compatible with the express-train model