Provenance study on coins minted at Elea/Velia (Italy). Pb isotope and Archaeometallurgy

The aim of this study is to trace the provenance of 20 Athena/Tripod bronze coins, coming from the Greek colony of Elea/Velia dating from 1st century BC (late Republic). The extensive use of lead, since ancient times, is due to its good malleability and relatively low melting point. It is well known from literature that lead, contained in the alloy of ancient coins, is useful for provenance study because it is not significantly affected by isotopic fractionation actions during manufacturing and coining processes. Both elemental and isotopic analyses were carried out at the Laboratori Nazionali del Gran Sasso (LNGS-INFN) in Assergi (AQ) by using ICP-MS (Inductively Coupled Plasma Mass Spectrometry), and TIMS (Thermal Ionization Mass Spectrometry) techniques. The concentration of lead in the samples under investigation ranges from fractions to tens of percentage units so a lead purification/preconcentration step by chromatographic resin columns was needed prior to TIMS analysis in order to assure reliable measurements. Lead isotopic ratios ranging from 1.170 to 1.197 and 2.076 to 2.082 for 206Pb/207Pb and 208Pb/206Pb, respectively, combined with archaeological and historical considerations have been used to identify the geographical origin of the raw materials used to produce these coins and to trace ancient trade routes and socio-economic relationships involving the city of Elea/Velia.