Social stratigraphy in Late Iron Age Switzerland: stable carbon, nitrogen and sulphur isotope analysis of human remains from Munsingen

The Iron Age cemetery of Munsingen in Switzerland with 220 abundantly equipped burials marked a milestone for Iron Age research. The horizontal spread throughout the time of its occupancy laid the foundation for the chronology system of the Late Iron Age. Today, skulls of 77 individuals and some postcranial bones are still preserved. The aim of the study was to obtain information about diet, mobility and social stratification of the individuals. Stable isotope ratios of carbon, nitrogen and sulphur were analysed for 63 individuals. For all of them, C-3 plants were found to be the staple food. There are significant differences between males and females in delta C-13 and delta N-15 values. This points to a gender restriction in the access to animal protein with males probably having more access to meat and dairy products. Differences in delta N-15 values were also observed for different age classes. delta S-34 values indicate a terrestrial-based diet with no significant intake of marine or freshwater fish. Seven adults with enriched delta S-34 values might have immigrated to Munsingen, four of which were found in the oldest part of the cemetery. Furthermore, possible changes of the vegetation are indicated by the more positive stable carbon ratios in the later phases. The results lead to the suggestion that especially males buried with weapons might have played a special role in the Iron Age society.