The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)

Integrating 87Sr/ 86Sr and δ18O values of archaeological enamel with geological and environmental water baseline isotopic data: A case study in geographic origins from Nasca, Peru


1Department of Anthropology, The University of Western Ontario, 2School of Human Evolution and Social Change, Arizona State University, 3Department of Earth Sciences, The University of Western Ontario

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Coastal South America is an environmentally and geologically complex region. Although both strontium and oxygen isotopic studies of geographic origins and residential mobility are becoming increasingly common, data interpretation is often hampered by a limited understanding of natural isotopic variation in the study region. Here, strontium-isotope data from soil and archaeological and modern fauna, and oxygen- and hydrogen-isotope data from environmental water samples from the Nasca drainage, are used to characterize baseline isotopic variability in the region. Strontium- and oxygen-isotope analyses of enamel from twenty individuals buried at the Nasca ceremonial centre Cahuachi are then used to explore childhood place of residence. We hypothesized that enamel strontium-isotope ratios would allow identification of extra-regional childhoods, and oxygen-isotope data would enable assessment of the intra-regional place(s) of origin for individuals buried at the site. Three individuals have enamel strontium-isotope ratios outside of the local range established in this paper, which suggests that they may have spent their childhoods outside of the Nasca region. Of the seventeen individuals local to the Nasca region, eleven have oxygen-isotope compositions consistent with a place of residence in the Southern Nasca Region middle valley (i.e., in the vicinity of Cahuachi), and six individuals most likely spent their childhood in other parts of the Nasca drainage. This study demonstrates that a more informative integration of strontium and oxygen isotopic data is possible through the use of regional environmental baselines to guide the interpretation of tissue isotopic compositions.

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