Strontium and stable isotope evidence for diet and mobility in Roman Gloucester, UK

This paper presents the results of a multi-isotopic (oxygen, strontium, carbon and nitrogen isotopes) investigation of population and dietary diversity in Roman Gloucester, focusing on individuals found in a late 2nd century AD mass burial pit at London Road, and comparing them to those found in the nearby cemetery. There were no statistical differences in isotopic composition between mass grave and cemetery burials, suggesting, in agreement with the osteological evidence, that the mass burial was the result of a catastrophic event, probably an epidemic disease. Strontium and oxygen isotope analysis demonstrated considerable diversity in the origins of the Gloucester population, with evidence for both UK and non-UK individuals. Diet was predominately terrestrial and similar to that of other Romano-British populations. Elevated δ13Cdentine ratios in some individuals are correlated with raised δ18Op values and are therefore probably due to childhoods spent in warmer climates, rather than dietary variation. Given the geological complexity of the Gloucester area, this study also provides new biosphere 87Sr/86Sr data for the wider region. A technical Appendix gives details of the analytical methods employed by the NERC Isotope Geosciences Laboratory (NIGL) for the measurement of oxygen stable isotope ratios in biogenic phosphate (δ18Op). It also evaluates different phosphate oxygen-drinking water conversion equations using data from Britain.