Scale of human mobility in northwestern Patagonia: An approach based on regional geology and strontium isotopes in human remains

Strontium isotopes facilitate the study of human paleogeography and have widened the scope of archaeological enquiries on mobility. We present an approach based on strontium isotopes (Sr-87/Sr-86) to study the mobility of hunter-gatherer societies from northwestern Patagonia (Neuquen, Argentina). The analysis is developed on the basis of a macro-regional geological framework that guides the sampling and interpretation of results. We also present results for fauna to begin building a landscape of bioavailable strontium to be utilized in the interpretation of results from human samples. These first results conform to general expectations and show the most radiogenic Sr-87/Sr-86 values for the oldest geological provinces, while low values are recorded for recent substrates. Additionally, we provide results for human samples from archaeological sites spanning the last 4000 years, a period during which a number of important socio-demographic changes occurred. The results in human samples indicate overall isotopic fidelity to the values recorded in the local geology, suggesting a relatively restricted spatial scale of mobility during the late Holocene. This discussion is situated in a biogeographic research framework assessing topographic variation and landscape seasonality, and contributes toward understanding the movements of people, flow of material objects, and circulation of information in the Patagonian Andes.