Stable Oxygen Isotope Analyses and Paleoenvironmental Reconstructions from Mollusks in Palau, Micronesia


Abstract. In Palau, Micronesia, marine resources such as shellfish played a vital role in subsistence for millennia. At the Chelechol ra Orrak site, nearly 100 shellfish species have been identified in archaeological assemblages, but there is a dearth of data on nearshore paleoecology or prehistoric shellfish foraging practices. To address these issues, we employed stable oxygen isotopes (δ18O) on select shellfish species, which has been successfully applied in many coastal regions to reconstruct paleoenvironments and sea-surface temperature (SST). In this study, modern shellfish samples were collected from intertidal zones near the site and ambient SST recorded. We then used X-ray diffraction on the samples to identify the skeletal biomineralogical composition, which provides the necessary information to select the proper isotope-to-SST conversion formula. Calcium carbonate samples were milled from modern shells and the δ18O results paired with ambient water temperatures using several δ18O-SST conversion equations. Using the most appropriate formula, these equations were then applied to δ18O samples from several prehistoric shells to reconstruct a high-resolution SST. Results provide useful baselines for examining a host of issues related to prehistoric subsistence strategies in Palau and how environmental changes may have influenced the availability and productivity of various molluscan taxa through time.

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Stable Oxygen Isotope Analyses and Paleoenvironmental Reconstructions from Mollusks in Palau, Micronesia. Taylor Dodrill, Mila Lassuy, Nicholas Jew, Scott Fitzpatrick. Presented at The 81st Annual Meeting of the Society for American Archaeology, Orlando, Florida. 2016 ( tDAR id: 404731)

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min long: 111.973; min lat: -52.052 ; max long: -87.715; max lat: 53.331 ;