Origin of French 14th to 16th century Alabaster Artwork from Ile-de-France assessed through multi-isotope Archaeometry (S, O, Sr)
Résumé
The trade roads of Medieval and Renaissance gypsum and anhydrite alabaster (CaSO4.2H2O and CaSO4) have so far been investigated mainly by art historians based on iconographic or stylistic comparisons. Unlikely to marble artwork, only few studies have so far addressed the mineralogical, geochemical and isotopic fingerprints of raw alabaster compared to those of alabaster sculptures [1-3]. A pilot study of isotope fingerprinting on French alabaster sculptures [4] has shown that sulphur and oxygen isotopes of gypsum can be used in combination with 87Sr/86Sr ratios to trace alabaster artwork back to the historical quarries from which the raw material was extracted. Samples of medieval and renaissance sculpture fragments of different provenance (Burgundy, Lorraine, Languedoc, Pyrenees) could be successfully and unambiguously linked to the ancient gypsum quarries from France (Jura, Alps, Provence, Burgundy, Lorraine), Spain (Aragon and Catalonia), England (Nottingham). Indeed the isotopic signatures of the different historical exploitations show high intra-group homogeneity and strong inter-group contrasts, main condition for forensic work on artwork provenance. Furthermore, the chosen analytical techniques (continuous flow IRMS, TIMS) permit the use of microsamples in the low mg range ensuring that damage to sculptures is minimal. The Louvre Museum currently undertakes an art-historical study on the provenance of its alabaster artwork of the Ile de France region and more generally of the North of France from the 14th to the 16th century and has included isotope characterization as a means to better constrain the hypotheses on alabaster trade during this period. The Louvre samples are completed by related alabaster artwork provided by the Cleveland Museum of Art and from the towns of Calais and Cluny. The data base of French historical raw alabaster is further extended, notably for the Burgundy region. Here we present first results on S, O and Sr isotope fingerprints of the Ile-de-France statuary and its relations with French, Spanish and English alabaster exploitations.