Provenance and recycling of ancient silver. A comment on Iridium to provenance ancient silver by Jonathan R. Wood*, Michael F. Charlton, Mercedes Murillo-Barroso, Marcos Martinon-Torres. J. Archaeol. Sci. 81, 1-12

It is argued that it is unlikely that iridium can be used as tracer for the provenance of ancient silver for geochemical reasons. Instead it is suggested that the observed low but measurable iridium concentrations may be due to silver produced from argentiferous gold by cementation. It is furthermore argued that the calculation of geological model ages from lead isotope ratios does not provide any additional information compared with the use of conventional three-isotope diagrams. (C) 2017 Published by Elsevier Ltd.