N. H. Gale

Bronze Age Copper Sources in the Mediterranean: A New Approach

Efforts by scientists to locate the sources of copper used in ancient Mediterranean and Near Eastern cultures through comparative chemical analyses of copper ores and archeological artifacts have largely failed for various mineralogical and metallurgical reasons. The isotopic composition of lead, an element present in a minor amount in many copper ores and bronze objects, is unchanged through metallurgical processes and may in principle be used to determine the sources of the copper used in Bronze Age artifacts. Results suggest that for Late Bronze Age Crete the Laurion region in Attica, Greece, may have been a more important copper source than Cyprus.

A lead-selective extraction chromatographic resin and its application to the isolation of lead from geological samples

Abstract A novel extraction chromatographic resin comprised of a 0.75 M solution of the macrocyclic polyether bis-4,4′(5′)-[tert.-butylcyclohexano]-18-crown-6 in isodecanol supported on an inert, polymeric substrate for the separation and preconcentration of lead from acidic media is described. The material is shown to retain lead efficiently and selectively over a wide range of nitric acid concentrations. Sorbed lead is readily recovered using any of a variety of complexing agents. The resin is demonstrated to be sufficiently stable to handle large sample volumes or to permit reuse. Application of the resin to the isolation of lead from geological samples for subsequent mass spectrometric determination of isotopic ratios is described.

Natural variations detected in the isotopic composition of copper: possible applications to archaeology and geochemistry

Abstract Copper isotopic compositions have been measured both in natural copper minerals from supergene/oxidation zones and in some ancient metal artefacts using two different instruments. Measurements were first made using a low temperature thermal ionisation technique with a thermal ionisation mass spectrometer (TIMS); independent data was obtained using a commercial inductively coupled plasma (ICP) magnetic sector multiple collector mass spectrometer. Significant variations of isotopic composition were found in both types of material, suggesting that there may be considerable potential for copper isotope analyses in metal provenance studies, at the least as a supplement to lead isotope studies. For minerals, δ values ranging from −1.63 to +7.71 were obtained, whilst archaeological artefacts had δ values from +0.22 to +4.32. This study also made a preliminary examination which suggests that fractionation of the isotopic composition of copper does not occur during smelting and fire refining processes thought to have been used in ancient times.

Cycladic Lead and Silver Metallurgy

Interest in the prehistory of the Cyclades may fairly be said to have been awakened in the middle of the nineteenth century when travellers like Walpole or Fiedler were intrigued by what we now regard as one of the characteristic products of ECII times in the Cyclades—the marble folded-arm figurines whose harmony, balance, and economy of artistic expression appeal so much to the admirers of twentieth-century artists such as Mondrian or Modigliani. Reports of other prehistoric material from the Cyclades soon followed from J. T. Bent, U. Kohler, and F. Dummler, whilst more systematic explorations began with the work of Edgar in Pelos, and Atkinson and others at Phylakopi on Melos.

A new method for extracting and purifying lead from difficult matrices for isotopic analysis

Abstract A new low blank separation scheme for lead is presented for the preparation of ultrapure lead samples for isotopic analysis by thermal ionisation mass spectrometry. The method benefits from the selectivity and high capacity of a new extraction Chromatographic material: Sr.Spec TM . The use of this material in HCl media, rather than the more usual HNO 3 media, affords a straightforward separation of Pb from complex metal ores with high yield, good purity and satisfactory blank levels on very small (0.1 ml) columns using small volumes of solutions of a single mineral acid. It has the advantages that it also separates Pb from Bi in the same column that separates Pb from matrix elements and that, unlike other low blank methods for Pb, it is directly applicable to the separation of traces of Pb from tin metal samples.

The Sources of Mycenaean Silver and Lead

Abstract Lead-isotope and neutron-activation analyses are reported for Greek Bronze Age lead and silver artifacts from the Shaft Graves of Mycenae, from the Athenian Acropolis and Agora, from Vapheio, Thorikos, Menidi, and Perati, and for lead-silver ores from Laurion, Attica. The analyses prove that mines at Laurion were being exploited for silver, lead being produced as a byproduct, from at least as early as Middle Helladic times, continuing into the Late Helladic IIICI period. The analyses show that the Laurion was the dominant, almost exclusive, source of these metals for the Mycenaean cultures, and they provide an estimate of the minimum silver content necessary in argentiferous lead to make it economically or technically possible to extract the silver by cupellation in Bronze Age Greece.

The Provenance of Lead Used at Ayia Irini, Keos

JN 1980, the authors of this paper began a study of the sources of lead and litharge recovered in the University of Cincinnati excavations at Ayia Irini on the Cycladic island of Keos.1 Our principal goal was to determine where the people of Keos obtained silver and lead in prehistoric times and to ascertain whether, over the long history of occupation at the site, there had been major changes in the sources exploited.2

Silver sources of archaic Greek coinage

We report on new chemical and lead isotopic results and interpretations of archaic Greek silver coins from the Asyut hoard which was buried around 475 B.C. Aeginetan coins were of central interest in this study. Possible ancient silver mines were explored in the Aegean region in the course of several geologic expeditions, and chemically and isotopically investigated. Some of the silver sources in Greece were traced by combination of the analytical methods and questions of provenance were solved. In addition, processes of silver smelting and refining were studied. Results and implications of this work are summarized in the final section on Conclusions.