Non-destructive magnetic and chemical characterization of granite column shafts traded in the Mediterranean area: the case of Piazza dei Miracoli in Pisa (Italy) and Basilica of Saint-Martin d'Ainay in Lyon (France)

International audienceWe present a scheme for non-destructive provenancing of granite shafts dating from the Roman to the medieval period using a combination of visual, magnetic, and chemical determinations. Our results on two monumental medieval complexes in Europe, in Pisa and Lyon, shows both oriental provenance, most likely spolia, and shaft from the quarries within the influence zone of the Pisa Republic (Elba, Corsica and Sardinia) that possibly correspond to shafts newly obtained in the quarries, particularly for the large diameter shafts of Ainay in Lyon (from Corsica) and Piazza dei Miracoli (from Elba and Sardinia). pXRF appears to be an efficient way to discriminate Corsican from Egyptian grey coarse grained granite provenance