Isotopic evidence from human bones for declining maize consumption during the Little Ice Age in central western Argentina

GIL, A; VILLALBA, R.; UGAN, A.; NEME, G.; CORTEGOSO, V.; MICHIELI, C; NOVELLINO, P.; DURÁN, V.

San Rafael

Workshop; IAI; 2014

CCT Mendoza/AIANIGLA

This study examines changes in human diets over the last 2500 years in central-western Argentina. Maize enters the archaeological record at the beginning of this period. It quickly increases in dietary importance, stabilizing at approximately 50% of the overall diet between the AD 800 and 1400. These data suggest that the most significant increase in maize consumption predated Inka occupation, coinciding with a similar trend in central Chile. Presumably, favorable climatic conditions associated with the long-term warm period from AD 1150-1370 facilitated the cultivation of maize in the region. After this time, the onset of cold conditions associated with the Little Ice Age induced changes in human diets in Central western Argentina and Central Chile. Declining stable isotope values after AD 1400 indicate a decrease in C4 inputs and, by extension, a drop in maize consumption. We propose that climatic conditions associated with a two-century long period of warm summers followed by the Little Ice Age had a significant role in that change. Without doubt, the arrival of the Inka and the Spanish impacted the physical and social environment as well, but all of these factors should be understood within a broad, ecological framework in order to generate a productive explanation of this variable time in our history. The incorporation of new resources, a diversification in subsistence strategies, mostly from Europe, and the changing role of preexisting ones can each be explored as possible subsistence responses to a time of sharp climatic change, and were undoubtedly only one part of a sweeping social and behavioral adjustments occurring at this time.