Some remarks on the use of geochemical tracers for metal provenancing

If properly used, geochemical tracers represent a powerful tool for metal provenance studies. Their discriminatory potential depends upon several factors, including the geological nature of the ore deposits, the availability of a comprehensive reference database, the nature of the artefact and, for trace elements, the evolution of manufacturing techniques. In some cases, an artefact can be traced back to its original metal source (an ore deposit or district) with very high confidence. In other cases, the interpretation may remain ambiguous, owing to geochemical overlaps between the different potential sources, use (or recycling) of metals of mixed origin, or scarcity of adequate reference data. In many cases, the geochemical analysis may at best allow one to reduce the number of possible sources by testing their geochemical compatibility with the investigated object. Combining various types of tracers, such as different isotopic ratios and trace elements, may significantly enhance the discriminant potential of the method. In any case, a correct geological understanding of the geochemical signatures of the different metal deposits is essential to avoid over-interpretations of the results and to constrain more effectively the area of metal provenance.