Mapping Strontium Isotope Geographical Variability as a Basis for Multi-regional Human Mobility: The Sybaris Region (S Italy) in the Early 1st Millennium BC

Abstract

ABSTRACT Archaeological findings from the 8th c. BC settlement at Francavilla Marittima (CS) and its necropolis on the nearby Macchiabate plateau point to multi-regional interactions and the emergence of new identities in connection with the establishment of the Greek colony Sybaris. Strontium isotope analysis (87Sr/86Sr) is an efficient method to reconstruct human mobility and provides new insights into the Iron Age and Archaic period in the Calabria region. A successful interpretation of Sr isotope compositions in human tissues requires a baseline of the bioavailable strontium in the landscape of Francavilla Marittima and its surroundings. This study presents 87Sr/86Sr values of modern vegetation and water from North Calabria to establish the first finely resolved Sr isotope baseline map of this region. Sr isotope compositions vary between 0.7082 and 0.7127 and reflect the geological and lithological diversity of the study region. The regional 87Sr/86Sr variability exceeds the baseline of bioavailable 87Sr/86Sr at Francavilla Marittima and enables the integration of past regional interaction in data interpretation of the human remains. Several mapping and prediction methods were tested to produce surface models of the isotopic landscape, and the isotope group map is proposed as a suitable representation of the bioavailable Sr in the studied region.