RECENT STABLE ISOTOPE STUDIES OF THE MOUNT PENTELIKON AND PARIAN WHITE MARBLE QUARRIES: A CALL FOR RIGOROUS GEOLOGIC FIELD WORK IN MARBLE PROVENANCE STUDIES

Stable isotope analysis of δ¹³C and δ¹⁸O is the primary analytical method for determining the provenance of white marbles used in the ancient Mediterranean. Since the publication of Herz's stable isotope database of ancient white marble quarries in 1985, many white marble monuments and sculptures have been sourced to their original quarries by matching their stable isotope ratios of carbon and oxygen to quarry signature fields within the database. To address potential gaps in the database North American and European researchers have undertaken field campaigns to collect and analyze additional samples from the same as well as newly discovered quarries. This work has increased the validity of the database; yet it has also broadened the range of stable isotope signature fields in δ¹³C – δ¹⁸O space causing overlaps of quarry signature fields and leading to less secure provenance assignments. A review of the published datasets of marble quarries reveals that very few, if any, of the sample collecting campaigns have undertaken detailed geologic field mapping. This paper shows that with detailed geologic field mapping the broad signature fields of some ancient quarries can actually be used to increase the resolution of the database and assign signature fields to specific subregions within a quarry region. This increased resolution can then be used to assign more precise provenance to marble artifacts. Two case studies will highlight the benefits of incorporating rigorous field mapping into sampling campaigns. In the first study, a high-resolution geologically correlated database of the Mount Pentelikon quarries in Greece reveals that marble was extracted from the very upper quarries of the northwest slope for the architectural sculptures of the Parthenon. The second study examines the current state of the Parian marble database and suggests that an apparent gap between the Lychnites and Choradaki marble types can be addressed through detailed geologic field work and analysis.