Trace elements and lead isotopic composition of copper deposits from the eastern part of the Internal Zone of the Betic Cordillera (SE Iberia): application to provenance of archaeological materials

Abstract

This paper presents trace element compositions and lead isotope analyses by MC-ICP-MS of 34 copper ore samples from the Internal Zone of the Betic Range, Southeast Spain. Samples were collected during a fieldwork campaign in the mines of Cerro Minado, Pinar de Bédar, Sierra Cabrera and Sierra Almagrera/Herrerías. Most samples are copper oxide minerals from the near surface alteration of the sulfide ore deposits. The aim of the study is to supplement the existing reference data bank on lead isotopic compositions of ancient copper mines from the Iberian Peninsula, complementing this data with trace element compositions. The latter can be useful for discriminating when isotopic overlaps occur. This characterisation will be of great usefulness for provenancing further archaeological materials. Lead isotope ratios range from 18.603 to 20.327 (206Pb/204Pb); from 15.685 to 15.779 (207Pb/204Pb) and from 38.728 to 39.702 (208Pb/204Pb). Data from the literature analysed by TIMS have been also considered for comparison although the larger analytical error is highlighted, especially for isotope 204Pb. The lead isotopic signature of the analysed samples shows three separate isotopic fields. These fields are also consistent with differences in compositions evidenced by principal component analyses.