This project entails accelerator radiocarbon dating (AMS) and stable isotope analysis of human remains from the Nuvuk Cemetery site at Point Barrow, Alaska. It is complimentary to genetic research directed by Dennis O'Rourke and M. Geoffrey Hayes (OPP-0732846) designed to establish the relationship between burials from this prehistoric cemetery, which are rapidly eroding into the Arctic Ocean, and modern groups now living both along the North Slope of Alaska and in the eastern Arctic. Previous research suggests that eastern Arctic groups originated at Point Barrow; however Nuvuk Cemetery lacks the chronological control necessary to anchor prehistoric genetic variability and provide the temporal framework needed to reconstruct migratory events. Here, the research team will extract and purify bone collagen from 100 individuals for AMS dating and stable carbon and nitrogen isotope analysis. The former procedure will establish much needed temporal control while the latter will allow the investigators to examine dietary patterning over the temporal span of the study. The research at Nuvuk is in collaboration with the community of Barrow, including the participation of Barrow high school students in research activities.
Proposal ARC-0820790 was funded by Arctic Social Sciences to accelerator radiocarbon date and analyze the stable isotope bone chemistry of human remains from the Nuvuk cemetery site at Point Barrow, Alaska. This request compliments research funded by the Office of Polar Programs: "Reconstruction of Human Genetic History Along the North Slope," with principle investigators Dennis H. O’Rourke and Geoffrey Hayes. ARC-0820790 funding was used to: 1) accelerator radiocarbon date the Nuvuk mortuary assemblage 2) and documents dietary patterning using the stable isotope chemistry of bone collagen (protein) and the mineral component of bone (apatite). 3) In addition, oxygen isotope signatures in bone apatite can serve as indicators of climate change by reflecting the temperature of drinking water. Of particular interest was detecting the Medieval Warm Period at ca. AD 950-1350, thought to be the impetus for Thule expansion into the Canadian high Arctic, one of the last great migrations in North American prehistory. Research Background In the summer of 2005, Dennis O’Rourke and students from the University of Utah began working with a Point Barrow archaeological team to recover and relocate prehistoric burials from the Nuvuk cemetery site. The Inupiaq village of Nuvuk is located at Point Barrow, the northernmost site in Alaska at the interface of the Chuckchi and Beaufort Seas. The cemetery site is currently eroding into the sea at a rate of 15-30m/yr threatening the loss of this ancient burial ground to storm surges and high sea levels. Elders of the Inupiaq community expressed interest in and gave permission for a scientific study of these remains and the possibility that they represent an ancestral population. Approximately 50 burials have been recovered. Isotope studies and radiocarbon dating on 32 of these burials is complete. Prehistoric Background: The Thule The Classic Thule coincide with the Medieval Warm Period, ca. AD 1000-1350, and are distinguished from later Thule adaptive strategies by greater winter sedentism, technological advances in weaponry, marked investment in residential structures and a distinctive material culture. This period saw the expansion of Thule material culture as far south as the Alaska Peninsula and the migration of Thule people into the eastern Arctic coincident with the opening of sea-lanes through the Canadian archipelago for summer-feeding whales, walrus and bearded seal. Post-dating the Classic Thule, Modified Thule material culture appears to indicate a reduction in the importance of whaling. Winter villages decline suggesting depopulation perhaps driven by a return to cooler temperatures. A reduction in the encounter rate of whales may have undermined Classic Thule social structure, organized under whaling captains, contributing to an overall decrease in population size. Foraging groups were more mobile and residential sites both more numerous and less complicated. Modified Thule subsistence patterns were much like those observed at European contact. Changes in Thule diet and settlement pattern vary regionally but generally coincide with the onset of Neo-boreal cooling, culminating in the "little ice age" (ca. AD 1550-1850). Radiocarbon Dating Results Nuvuk burials (n=32) have a two-sigma age range of AD 1066-1663 with confidence interval median values between AD 1189-1579; thus Nuvuk burials date from the Classic Thule through the Modified Thule period. Importantly, some of these burials date to the era of Thule migrations into the eastern Arctic. Thus, their genetic signatures provide information regarding the origins of eastern Arctic and Greenland Thule populations and are consistent with an exclusive Thule ancestry for modern Inupiat/Inuit groups. Radiocarbon dates also indicate that these burials spanned the Medieval Warm period to Neo-boreal cooling, with a few individuals dating as late as the Little Ice Age. However, Nuvuk oxygen isotope values do not co-vary with these broad patterns of climate change. Instead, results suggest that the small number of burials analyzed is not adequate to reflect gradual but fluctuating reductions in the temperature of precipitation. Dietary Results Nuvuk stable isotope values on bone collagen show diets high in high trophic level marine mammals such as seal. Whales, walrus, fish and sea birds were also important in these diets and marine foods made up an average of 70 % of caloric intake, similar to the diets of Thule foragers from archaeological sites along the Hudson Bay in the eastern Arctic. Prehistoric Arctic forages typically lack a carbohydrate staple, which makes up the energy component of most diets. Instead Arctic foragers relied upon the blubber of sea mammals to provide energy and micronutrients, like vitamin C, missing from high meat diets. Accordingly, the use of sea mammal lipids for energy is also reflected in the bone chemistry of Nuvuk burials. Dietary patterning is in keeping with the archeological and historic record for Point Barrow. For more than a millennium these high Arctic foragers exploited both marine and land-based animal resources persisting in a challenging environmental setting at one of the northern-most occupied sites in North America.
