Archaeology of fuel use in Northwestern Alaska: multi-proxy analyses to explore Birnirk and Thule culture fuel economy at Cape Espenberg

International audienceWe present a study regarding fuel availability at the sites of Cape Espenberg in northwestern Alaska, based on data from post-AD1000 archaeological sites. Our long-term goal is to explore fuel management patterns in a wood-poor arctic environment. Birnirk and Thule inhabitants at Cape Espenberg (AD XIth-XVth centuries) used driftwood as fuel, but often mixed it with nonwood fuel (bones, fat, etc.). Large burned areas are found associated with most house features, raising questions regarding the uses of fire, as well as the functions of these hearth and burnt areas for different time periods. We developed a multidisciplinary approach to explore fuel practices in this region using soil micromorphology, anthracology and experimental combustions. The complementarity of these approaches is key to providing information about the functions of combustion features. Under controlled laboratory conditions and outdoors with local conditions, we conducted experimental fires, using either wood fuel or mixed wood-fat fuel (either terrestrial or marine mammal fat). These experimental combustions provide information about the impact of fat on the temperature and duration of fire, the formation of soil crusts, and agglomerated organic residues. Analysis and identification of charcoal remains suggest strong contrasts in the representation of wood taxa and the preservation of charcoal between wood-only and fat-added experimental fires. The implication of these results are discussed in relation to the analysis of burnt areas at Cape Espenberg