Sr isotopic composition as a tool for unraveling human mobility in the Campania area

Recent strontium isotope ( 87 Sr/ 86 Sr) analyses of bones and teeth have provided useful archeological results for reconstructing past human migration and diet. We report 87 Sr/ 86 Sr ratios and DNA analyses of tooth enamel from individuals buried in some necropolises in Nola town, near Napoli (Campania, South Italy). These individuals lived in the period between the Avellino (1925 years BCE) and CE 472 Pollena Vesuvian eruptions and are dated on archeological basis to the time span between the sixth and second century BCE. Tooth enamel 87 Sr/ 86 Sr ratios (0.70788–0.70864) are higher than baseline values in the necropolises (0.70756–0.70792): this can be explained by assuming either that all the analyzed individuals are not local—an unlikely possibility—or that they ate both local and foreign food (within about 50 km), including 87 Sr-rich seafood. An explanation for such a varied diet might be that the individuals from Nola were living near the Ancient Appia and Popilia ways and not far from the coastline. Whatever its origin, the 87 Sr/ 86 Sr ratios represent the isotopic signature of the local community living on the slopes of Mt. Somma-Vesuvius between the sixth and second centuries BCE. This knowledge will support future isotope studies on volcanic eruptions as possible causes of human migration.