Trade routes across the Mediterranean: a Sr/Nd isotopic investigation on Roman colourless glass

In this study analysis of major elements and Sr-Nd isotopes is performed on 33 colourless glass fragments from two Roman shipwrecks discovered in the Northern Mediterranean Sea, the Julia Felix (first half of the third century AD) and the Ouest-Embiez (end of the second beginning of the third century AD). Two compositional groups are defined based upon the major elements analysis, suggesting the use of different raw materials, and possibly the production of the glass samples in two separate factories. Sr-Nd isotopes, promising indicators for provenancing geological resources used as raw materials in glass manufacturing, confirm the compositional groups. The Sr-87/Sr-86 signature is very close to the modern sea water signature (0.7092) for all samples, likely due to the use of shell as glass raw material. The Nd signature further subdivides the compositional groups, suggesting the use of three different sand raw materials for the production of glass.