Strontium-scapes, cultural change, and human life histories in the southern Andes

BARBERENA, RAMIRO; LE ROUX, PETRUS; TESSONE, AUGUSTO; GASCO, ALEJANDRA; NOVELLINO, PAULA; LLANO, CARINA; LUCERO, GUSTAVO; CORNEJO, LUIS; DURÁN, VÍCTOR; CORTEGOSO, VALERIA; FALABELLA, FERNANDA; FRIGOLÉ, CECILIA; MARSH, ERIK; MÉNDEZ, CÉSAR; NUEVO DELAUNAY, AMALIA; SANHUEZA, LORENA; SANTANA-SAGRADO, FRANCISCA; TRONCOSO, ANDRÉS; BENÍTEZ, ANAHÍ; WINOCUR, DIEGO

Dublin

Congreso; International Union for Quaternary Research; 2019

The main goal of this paper is to reconstruct the spatial scales and patterns of organization of human mobility across a diverse array of ecological and altitudinal settings across the southern Andes (32o-34o S) during the last 2500 years. This project is designed to sample different biogeographic regions from the Pacific coast in Chile to the eastern Andean lowlands in Argentina (Figure 1). To achieve this long-term goal, we present advances in the following two specific goals of the project.Firstly, we seek to build a framework of bioavailable strontium isotopes (87Sr/86Sr) as expressed in the main Andean geological units, which span from the Pliocene to the Lower Paleozoic: a) marine Sr in the Pacific coast; b) Coastal Cordillera (Cretaceous); c) Western Principal Cordillera (Miocene-Oligocene); d) Eastern Principal Cordillera (Cretaceous-Jurassic); e) Frontal Cordillera (Permian-Triassic); f) Precordillera (Lower Paleozoic); and e) Active Foreland (Quaternary) (Figure 2). To achieve this goal, we analyze plants and rodent samples from modern and archaeological contexts. This is the first attempt to apply such an approach in the southern Andes.Secondly, by analyzing strontium isotopes in human bone and teeth samples from archaeological contexts, we reconstruct place of origin and death, providing an analytical window for the study of individual life histories, combining the realms of quotidian ranges of human movement and social processes, such as conflict and migration, which disrupt this pattern of daily life. We focus on the analysis of human remains from the last 2500 years, witnessing the most intense processes of socio-demographic and economic change, including an apparent reduction in the intensity of mobility, first presence of archaeological cemeteries, the origins of agro-pastoral economies, and the geographic expansion of the Inka Empire.From a methodological perspective, we develop a preliminary comparison of strontium and oxygen isotopes (18O/16O), revealing a divergent pattern: while oxygen isotopes for human samples from distant regions in western Argentina overlap widely, there are important differences in strontium isotopes, hence suggesting that strontium provides a finer tracer of human mobility across this geologically complex Andean landscape. Our strontium results will be briefly compared to those produced by colleagues for the south-central Andes of southern Peru, northern Chile, and western Bolivia, in an attempt to learn about the spatial resolution achievable in different Andean geological settings. In synthesis, by integrating the results for bioavailable strontium and human tissues in the context of a biogeographic framework, this project (National Geographic HJ-136R-17) presents the first assessment of sociocultural variation, scales of human territories, and patterns of social interaction across the southern Andes.