Temporal, spatial and gender-based dietary differences in middle period San Pedro de Atacama, Chile: A model-based approach

Abstract

To explore the possible emergence and lived consequences of social inequality in the Atacama, we analyzed a large set (n = 288) of incredibly well preserved and contextualized human skeletons from the broad Middle Period (AD 500-1000) of the San Pedro de Atacama (Chile) oases. In this work, we explore model-based paleodietary reconstruction of the results of stable isotope analysis of human bone collagen and hydroxyapatite. The results of this modeling are used to explore local phenomena, the nature of the Middle Period, and the interaction between local situations and the larger world in which the oases were enmeshed by identifying the temporal, spatial, and biocultural correlates and dimensions of dietary difference. Our analyses revealed that: 1) over the 600-year period represented by our sample, there were significant changes in consumption patterns that may evince broad diachronic changes in the structure of Atacameño society, and 2) at/near 600 calAD, there was a possible episode of social discontinuity that manifested in significant changes in consumption practices. Additionally, while there were some differences in the level of internal dietary variability among the ayllus, once time was fully considered, none of the ayllus stood out for having a more (or less) clearly internally differentiated cuisine. Finally, sex does not appear to have been a particularly salient driver of observed dietary differences here. While we do not see any de facto evidence for complete dietary differentiation (as there is always overlap in consumption among individuals, ayllus, and time periods, and as isotopic analysis is not capable of pinpointing different foods items or preparations), there are broad aspects of dietary composition changing over time that are potentially linked to status, and foreignness. Ultimately, these stand as the clearest example of what has been termed "gastro-politics," potentially tied to the emergence of social inequality in the San Pedro oases.

Fig 1. Map of San Pedro de Atacama, with locations referenced in texts noted.

Fig 2. Correlation matrix of radiocarbon dates and sample quality metrics.

Fig 3. Correlation matrix of sample quality metrics and measured isotope values.

Fig 4. Scatterplot of δ¹³C and δ¹⁵N of foodgroups used in FRUITS paleodietary modeling.

Fig 5. Correlation matrix of measured isotope values and individual modeled foodgroup contributions.

Fig 6. Boxplot of average mean modeled contribution, by foodgroup.

Fig 7. Scatterplot matrix of modeled median calibrated radiocarbon dates and mean modeled contribution, by foodgroup.

Fig 8. Scatterplot of unmodeled and modeled median calibrated radiocarbon dates.

Fig 9. Violin plot matrix comparing pre- and post-600 calAD mean modeled foodstuff contributions.

Fig 10. MDS plot of FRUITS modeled foodgroup contributions, by ayllu.

Fig 11. Violin plot matrix of radiocarbon date-regressed modeled foodgroup contributions by ayllu.

Fig 12. MDS plot of radiocarbon date-regressed modeled foodgroup contributions by ayllu.

Fig 13. Violin plot of modeled median calibrated radiocarbon dates by sex.

Fig 14. Violin plot matrix of FRUITS mean modeled foodstuff contributions by sex.

Fig 15. MDS plot of FRUITS modeled foodgroup contributions, by ayllu and sex.

Fig 16. MDS plot of radiocarbon date-regressed modeled foodgroup contributions by ayllu and sex.

Fig 17. MDS plot of radiocarbon date-regressed modeled foodgroup contributions by ayllu and sex with “cluster” of female values and greater dispersion of male values noted by ellipses.