Migration, violence, and the “other”: A biogeochemical approach to identity-based violence in the Epiclassic Basin of Mexico

Abstract

Bioarchaeological studies are highly successful in accessing multivalent past social identities. This study applies social identity theory to contexts of violence, developing a theoretical framework to investigate identity-based violence at the Epiclassic (600–900 CE) central Mexican shrine site of Non-Grid 4, where at least 180 individuals were ritually sacrificed and interred. Ethnohistoric and archaeological data indicate that geographic origin was a culturally significant indicator of social difference in pre-Hispanic Mesoamerica. This study therefore reconstructs the residential histories of sacrificed individuals (n = 73), analyzing radiogenic strontium (87Sr/86Sr) and stable oxygen (δ18O) isotopes to consider how the perception of social difference, inferred from geographic origins, contributed to the selection of victims of ritual violence. Biogeochemical results demonstrate that 70% of sampled sacrificed individuals were born and lived their early lives outside of the Basin of Mexico, migrating into the region later in life. In contrast, only 22% of individuals were born and lived in the Basin their entire lives. Observed paleomobility patterns among sacrificial victims thus suggest that they were targeted for identity-based violence based on their divergent geographic origins in the volatile socio-political landscape of the Epiclassic Basin of Mexico.