A palaeodietary investigation of carbon (13C/12C) and nitrogen (15N/14N) in human and faunal bones from the Copper Age cemeteries of Varna I and Durankulak, Bulgaria

Stable isotope analyses have been applied to human and faunal bone collagen from the Varna I and Durankulak cemeteries to explore palaeodietary adaptations in the Neolithic and Eneolithic (Copper Age). The results suggest both populations primarily utilised terrestrial, C3-based diets, despite their proximity to the Black Sea. The wider δ15N range of the Durankulak humans likely indicates the differential utilisation of terrestrial meat sources, which is probably related to the degree to which primary and/or secondary ovicaprid products were consumed, particularly since ovicaprid δ15N values differ from other herbivores. The isotopic distribution of Varna I reflects a linear relationship between δ15N and δ13C, suggesting that a minority of individuals enriched in both isotopic parameters supplemented their diets with marine resources. These burials include the well known ‘chieftain’ (burial 43) and show notable material wealth by way of grave goods. At the population level, however, there is no significant correlation between stable isotope values and material wealth at Varna I, a fact with implications for theories regarding emergent social/economic hierarchies in Balkan prehistory. Five burials at Durankulak were found to have relatively enriched δ13C and δ15N values with respect to the rest of the population. These burials reflect a prominently marine-based or mixed terrestrial C3-based diet that included C4 inputs, possibly from millet, for which the limitations of stable isotope analysis on bulk collagen are not able to differentiate. AMS dating has shown that these burials belong to a much later period.