Isotopic ecology and human palaeodiets in the lower basin of the Colorado River, Buenos Aires province, Argentina

Abstract

Results of stable isotope analyses are presented for the study of human subsistence in the lower basin of the Colorado River, Buenos Aires province, Argentina. This paper provides the most current state of knowledge concerning isotopic research in the study area, which in turn sheds new light on such a significant region as the Pampa-Patagonia transitional zone, spatially related to the Atlantic coast. In addition, information from the middle basin of the Negro River is incorporated in the analysis and discussion. Both the construction of an isotopic ecology and the prehistoric human diets derived from δ 13C and δ15N human isotope values for the area are explored. Stable isotope analysis of modern plants indicates a C3 plant-based environment. Animal resources have δ13C values that indicate a diet based mainly on C3 products. Nevertheless, they have highly variable δ 15N values. Human isotopic values have the following mean values: -18.8%‰±1.08%‰ for δ 13CCOL (n=25), and 11.98%‰±1.34%‰ for δ15N (n=25). As a general trend, the results obtained from both C and N isotopic signals indicate a diet based on the consumption of protein provided by meat of terrestrial herbivores (e.g. artiodactyls) with the complement of fish. These results are in agreement with the data obtained from the zooarchaeological record for the Late Holocene.