Defining a ‘reasonable geographic framework’: Path Distance as native copper provenance in the Arctic, Subarctic, and Northwest Coast

The relative purity of geologic native copper, compared to other raw materials such as obsidian, creates challenges for conducting provenance research. Accurate provenance also depends upon a robust dataset of trace element variation within geological sources. These challenges combine in Northwest North America where three native copper source regions (Central Arctic, Western Subarctic, Northwest Coast) supplied multiple technological traditions in native copper through time. This paper utilizes Path Distance models of human mobility and interaction with the landscape as a proxy for geochemical provenance to estimate a ‘reasonable geographic framework’ (sensu Rapp et al., 2000:96) of the geologic origins of copper artifacts spread across Northwest North America. Generated Path Distance values often link archaeological sites with geologic sources different than when using simple Euclidean distances. Because of their generation using real-world variables to estimate mobility, these values can also be considered a proxy for ‘acquisition cost’ – the cost in time, energy, and social capital spent to acquire raw material – that can frame the analysis of variation in copper and other materials-based technologies in the future.