Conceptual Model of Permafrost Degradation in an Inuit Archaeological Context (Dog Island, Labrador): A Geophysical Approach

Abstract

Characterizing permafrost is crucial for understanding the fate of arctic and subarctic archaeological archives under climate change. The loss of bio-physical integrity of archaeological sites in northern regions is still poorly documented, even though discontinuous permafrost is particularly vulnerable to global warming. In this study, we documented the spatial distribution of the permafrost-supported Inuit archaeological site Oakes Bay 1 on Dog Island (Labrador, Canada) while employing a novel approach in northern geoarchaeology based on non-invasive geophysical methods. ERT and GPR were successfully used to estimate active layer thickness and image permafrost spatial variability and characteristics. The results made it possible to reconstruct a conceptual model of the current geocryological context of the subsurface in relation to the site topography, hydrology, and geomorphology. The peripherical walls of Inuit semi-subterranean sod houses were found to contain ice-rich permafrost, whereas their central depressions were identified as sources of vertical permafrost degradation. The geophysical investigations were used to classify the permafrost at Oakes Bay 1 as climate-driven, ecosystem-protected permafrost that cannot regenerate under current climate conditions. This work highlights how the permafrost at Oakes Bay 1 is currently affected by multi-point thermal degradation by both conduction and advection, which makes it highly sensitive to climate warming.