Reconstructing Subneolithic and Neolithic diets of the inhabitants of the SE Baltic coast (3100-2500 cal BC) using stable isotope analysis

We present 9 accelerator mass spectrometry (AMS) dates and 41 carbon and nitrogen stable isotope measurements on bone and tooth collagen from the Sventoji Subneolithic/ Neolithic sites and the Benaiciai cemetery, both in NW Lithuania. These data have led to a revised chronology and to the creation of a comprehensive stable isotope baseline for the Subneolithic and Neolithic periods at the SE Baltic coast. The Benaiciai cemetery has been AMS redated from the Late Bronze Age to the Neolithic, i.e., 2600/2500 cal BC. After a freshwater radiocarbon effect (FRE)/marine radiocarbon effect (MRE) correction to the AMS dates of isolated human bones found at the Sventoji sites, a date range of 3100-600 cal BC was established. Stable isotope data obtained from isolated human bones from Subneolithic coastal sites indicate that these originated from a local "lagoonal" people who relied heavily on freshwater fish species despite the proximity to the Littorina Sea. Seals and terrestrial animals were only of secondary importance in terms of diet. A non- routed dietary model, with zooarchaeological priors included, created with the Bayesian package FRUITS gave results that were consistent with expected FRE/MRE offsets. Stable isotope data of two Benaiciai graves indicate a sharp dietary shift towards terrestrial protein that occurred between 2700 and 2500 cal BC in the Sventoji River basin. This is contemporaneous with the arrival of both Corded Ware Culture stockbreeders and the beginning of a natural and significant reduction in the productivity of lagoonal lake ecosystems.