Lead isotopes in Celtiberian denarii from Turiasu and Roman asses minted in cities of the Conventus Caesaraugustanus (Hither Spain)

Abstract

Isotope analysis is a flexible and powerful tool for provenance studies of archaeological objects. In the present study, lead isotopic analysis was used in order to gain insight into the origin of the mineral sources of coins minted in the Celtiberian mint of Turiasu and in six coloniae and municipia of the Conventus Caesaraugustanus (Hither Spain) under Augustus and Tiberius (27 BC-37 AD). In the case of Turiasu denarii, argentum from the Iberian Range mines was used, and in the Roman asses coined in civitates of the middle Ebro River, the copper minerals had a diverse origin (Pyrenean, from the Iberian Range, from the southeastern Iberian Peninsula and from the Central Iberian Zone). Differences in ore provenance and in bulk composition (investigated through X-ray fluorescence) were not only detected among the early Augustan, late Augustan and early Tiberian periods, but also among the mints under study. Moreover, differences were also detected among the mints of the Conventus Caesaraugustanus and the official mint of Rome, evidencing that the former enjoyed autonomy in terms of the choice of ore origin and processing.