Bioavailable Strontium in the Southern Andes (Argentina and Chile): A Tool for Tracking Human and Animal Movement

Abstract

Strontium isotopes allow tracking the scale and pattern of movements of people and animals. With the ultimate goal of reconstructing human mobility in the southern Andes (Argentina and Chile), we present isotopic values for rodent samples selected from the main geological units, thus contributing to building a macro-regional framework of bioavailable strontium. The results show an important variation between geological units with little isotopic overlap between the young western Principal Cordillera (0.70393 ± 0.0005), Eastern Principal Cordillera (0.70563 ± 0.0001), Frontal Cordillera (0.70670 ± 0.00087), and the old Precordillera (0.70946 ± 0.00073) east of the Andes. This substantiates the potential of this approach for archaeological and paleoecological analyses in the southern Andes. We also present the first set of isotopic results for wild and domesticated camelids from the southern Andes, suggesting that home ranges were similar. We reconsider published results for human samples from the last 2000 years in Mendoza Province (Argentina), a period characterised by intense socio-economic change. The observed pattern suggests little systematic human mobility between geological regions across the Andes. While this may not necessarily indicate low mobility, it clearly goes against scenarios of high residential mobility, as suggested on the basis of other isotope systems.