An updated petrographic and isotopic reference database for white marbles used in antiquity

The identification of the quarry of provenance of ancient marble artefacts is, on the one hand, of the utmost interest to archaeologists and art historians, on the other hand, one of the most debated problems of petro-archaeometry. Scholars of different disciplines (geosciences, chemistry, physics) have been trying for more than a century such identification by means of a unique or multiple laboratory analysis without totally positive results in absence of non-destructive techniques. To date, the best probabilities of success are obtained by combining together at least two analytical methodologies and jointly processing all the data obtained. In particular, the detailed minero-petrographic examination of a thin section and the determination of the C and O stable isotopic ratios on the same sample is currently the most widely used and reliable combination. Such a combination takes advantage of the most updated existing databases for the main Mediterranean marbles very commonly used in classical antiquity. On the basis of a complete scrutiny of the recent literature data published from 2002 to 2012, we propose here an upgrade and reorganization on a geographic base of the petrographic and isotopic databanks based on hundreds of analyses relative to the marbles from the major and some minor quarries active in Greek and Roman times. These new data allow to increase the statistical significance of the whole database and draw new global reference isotopic diagrams related to the maximum grain size (MGS) of the different marbles proving very useful to better determining the provenance of a given archaeological/historical marble objects.