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Bronze coins coming from the area of the Mediterranean basin, dated back the II–X Cent. A.D., were analyzed using different physical analytical techniques. Characteristic X-ray fluorescence was used with electrons and photons, in order to investigate the elemental composition of both the surface layers and bulk. Moreover, the quadrupole mass spectrometry coupled to laser ablation (LAMQS technique) in high vacuum was used to analyse typical material compounds from surface contamination. Mass spectrometry, at high resolution and sensitivity, extended up to 300 amu, allowed measuring the 208 Pb/ 206 Pb and 207 Pb/ 206 Pb isotopic ratios into the coins. Quantitative relative analyses of these isotopic ratios identify the coin composition such as a “fingerprint” depending on the mineral used to extract the lead. Isotopic ratios in coins can be compared to those of the possible minerals used to produce the bronze alloy. A comparison between the measured isotope ratios in the analyzed coins and the literature database, related to the mineral containing Pb as a function of its geological and geophysical extraction mine, is presented. The analysis, restricted to old coins and the mines of the Mediterranean basin, indicates a possible correlation between the coin compositions and the possible geological sites of the extracted mineral. [ABSTRACT FROM AUTHOR]

Abstract: Ancient silver coins of different historical periods going from IV cent. B.C. up to recent XIX century, coming from different Mediterranean countries have been investigated with different surface physical analyses. X-ray photoelectron spectroscopy (XPS) analysis has been performed by using electron emission induced by 1.4keV X-rays. X-ray fluorescence (XRF) analysis has been devoted by using 30keV electron beam. Scanning electron microscopy (SEM) has been employed to analyze the surface morphology and the X-ray map distribution by using a 30keV microbeam. Techniques were used to investigate about the patina composition and trace elements as a function of the sample depth obtained coupling XPS to 3keV argon ion sputtering technique. [Copyright &y& Elsevier]