APPLICATIONS OF HEAVY ISOTOPE RESEARCH TO ARCHAEOLOGICAL PROBLEMS OF PROVENANCE AND TRADE ON CASES FROM AFRICA AND THE NEW WORLD

Abstract

Applications of lead and strontium isotope analysis were made on archaeological materials from three different contexts in both the Old and New Worlds. These materials comprised pre-Hispanic glaze painted ceramics from Arizona, U.S.A., glass beads from late first millennium AD Igbo-Ukwu, Nigeria, and copper-based metals from early first millennium AD Kissi, Burkina Faso. All materials contain lead at major, minor, or trace concentrations, and lead isotope analysis was employed to determine a provenance for that lead. Strontium isotope analysis also was applied to glass beads from Igbo-Ukwu to determine provenance(s) for strontium found in the glass. Furthermore, application of elemental composition analysis was or had been employed on all samples for additional data comparisons within assemblages and with comparable archaeological materials.Results of these analyses determined, in most cases, regional provenance with high degrees of confidence for lead contained in the analyzed samples. Strontium and elemental composition analysis data also proved valuable in confirming the regional provenance of the raw glass used to produce the glass beads. Leads in the glaze paints from Arizona, which demonstrated a range of resources exploitation, were confidently restricted to a few regions for their procurement. Likewise leads in most glass beads from Igbo-Ukwu were confidently restricted to two main source regions, with a third strong contender also being identified. The elemental composition and strontium isotope data determined with confidence the production regions for the primary raw glasses used to make the glass beads. Finally, leads in copper-based metals from Burkina Faso also were restricted to a few regions, although some inconclusiveness in provenance determination was attributed to mixing of metals from difference sources.These results confirm the utility of heavy isotope analysis of archaeological materials for provenance determination. The combination of these data with elemental composition analyses further confirm the interpretive strength of combining independent but related sets of analytical data for exploring questions of archaeological provenance. With improvements in instrument technology and application in the past two decades, very high precision and high accuracy analyses can be made which eliminate some earlier concerns of heavy isotope applications in archaeology.