Isotopic composition of lead for raw material tracing: the case of Roman lead-glazed ceramic

Numerous studies of glazed coatings on ancient ceramics aimed at understanding the ancient production process, how it changed and developed through the centuries (Tite et al., 1998; Özçatal et al., 2014). In addition, investigating the provenance of the raw materials involved in glaze production is important to reconstruct the main trade routes that disseminated this technology. Stable lead isotope analyses, using secondary ion mass spectrometry (SIMS), was applied to trace the provenance of lead minerals involved in the production of Roman lead-glazed ceramics. The fragments analyzed here were unearthed in different archaeological contexts of ancient Rome (Testaccio Market, Magna Mater sanctuary and Domus Tiberiana on the Palatine Hill, Forum of Caesar and Forum of Nerva), spanning the period from the 2nd Century AD to the Middle Age. The ceramics analyzed clustered within the distribution patterns of several deposits including Bulgaria, Italy (Sardinia), Greece and Britain. However, the comparison with the lead isotope data of ores by statistical treatment of the data (PCA) shows that the deposits from England were important sources of lead used for the production of glazed ceramics since the second Century AD. A comparison of our lead isotopic results obtained using SIMS with data collected from previous works by ICP-MS and TIMS (Wolf et al., 2003; Walton & Tite, 2010) shows that SIMS can be used for lead isotope provenance research. In addition, SIMS micro-analytical technique includes easy sample preparation, quick acquisition times, and is minimally destructive, which are advantages in the field of cultural heritage (Hull et al., 2014). Furthermore, the acquisition of accurate and precise isotopic measurements on a micrometer scale with the possibility to choose the location of each analysis point avoids the inclusions especially in the case of ceramic materials