Thule whaling at Point Barrow, Alaska: The Nuvuk cemetery stable isotope and radiocarbon record

Coastal erosion on the Point Barrow, AK, spit necessitated salvage excavation of the Nuvuk cemetery. Purified bone collagen extracted from 54 Thule era burials was analyzed for stable carbon (δ13C) and nitrogen (δ15N) isotopes values and accelerator radiocarbon dated. The highly enriched nitrogen isotope chemistry of these burials indicates the Nuvuk were apex marine predators with heavy reliance on high trophic level marine taxa, primarily beluga whales and ringed and bearded seal. Bowhead whaling made a less significant contribution to sampled diets despite its social currency. In contrast, carbon isotope values suggest significant terrestrial inputs to Nuvuk diets. Comparative data from Aleutian and eastern Arctic marine foragers further confound what appear to be conflicting results. Yet modern polar bear along the Beaufort Sea shelf show isotopic patterning very similar to that of the Thule at Nuvuk. We suggest that depleted Nuvuk δ13C values result primarily from the discharge of riverine, terrigenous carbon into the Beaufort Sea during spring, freshwater runoff. The deposition of large amounts of terrigenous carbon prior to the melting of landfast ice contributes to an isotopically deleted estuarine-like, near-shore food web. A local ΔR correction to marine reservoir effect was used to calibrate AMS radiocarbon dates. Results are supported by paired two-sigma age ranges on burials and associated terrestrial grave materials.