Species-specific reservoir effect estimates: A case study of archaeological marine samples from the Bering Strait

Due to the marine reservoir effect, radiocarbon dates of marine samples require a correction. Marine reservoir effects, however, may vary among different marine species within a given body of water. Factors such as diet, feeding depth and migratory behaviour all affect the C-14 date of a marine organism. Moreover, there is often significant variation within single marine species. Whilst the careful consideration of the Delta R values of a single marine species in a given location is important, so too is the full range of Delta R values within an ecosystem. This paper illustrates this point, using a sample pairing method to estimate the reservoir effects in 17 marine samples, of eight different species, from the archaeological site of Ekven (Eastern Chukotka, Siberia). An OxCal model is used to assess the strength of these estimates. The marine reservoir effects of samples passing the model range from Delta R (Marine20) = 136 +/- 41-Delta R =460 +/- 40. Marine reservoir effect estimates of these samples and other published samples are used to explore variability in the wider Bering Strait region. The archaeological implications of this variability are also discussed. The calibrating of C-14 dates from human bone collagen, for example, could be improved by applying a dietary relevant marine reservoir effect correction. For humans from the site of Ekven, a Delta R (Marine20) correction of 289 +/- 124 years or reservoir age correction of 842 +/- 123 years is suggested.