Stable Lead Isotope Studies of Central Taurus Ore Sources and Related
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Yener, K. A., et al. "Stable Lead Isotope Studies of Central Taurus Ore Sources and Related Artifacts from Eastern Mediterranean Chalcolithic and Bronze Age Sites." Journal of Archaeological Science, v. 18, no. 5 (Sept. 1991), pp. 541-577. © Academic Press, Ltd. Journal ofArchaeological Science 1991 , 18, 541- 577 .,, Stable Lead Isotope Studies of Central Taurus Ore Sources and Related Artifacts from Eastern Mediterranean Chalcolithic and Bronze Age Sites K. A. Yenera ,E. V. Sayre,a E. C. Joel,a" H. Ozbal b ,1. L. Barnes c and R. H. Brilld (Received 1 March 1990, revised manuscript accepted 27 November 1990) This is the first paper in a series presenting stable lead isotope studies of geological and archaelogical specimens obtained in 7 years ofarchaeometallurgical surveys in Turkey. The geological specimens presented here are ore and slag samples taken from ancient mining sites in the Central Taurus mountain range. The archae logical specimens are metal objects, dating to the Chalcolithic and Bronze Ages, from Anatolia, Syria, Mesopotamia, Greece and the Aegean. The isotopic measurements on these speci mens have been made and statistically analysed as part ofa collaborative effort between the Smithsonian Institution Conservation Analytical Laboratory and the United States National Institute of Standards and Technology (NIST). A comprehensive data base of approximately 1000 stable lead isotope measurements on such Eastern Mediterranean specimens has been formed QY combining the accumulated measure ments at NIST with analyses published in the literature. The overlap between speci mens in the overall data bank and the Central Taurus source specimens provides a realistic evaluations of the effectiveness of the use of stable lead isotope measurements for metallic ore source characterization and for the recognition ofexchange patterns of metal and metal artifacts in the formative periods of metallurgy. Keywords: LEAD ISOTOPES, METALS, ARTIFACTS, CENTRAL TAURUS, EASTERN MEDITERRANEAN, CHALCOLITHIC, BRONZE AGE. Introduction It has long been acknowledged that the highland regions of Anatolia were among the earliest environments in which metallurgy developed (Craddock, 1985; Tylecote, 1987). Scholars studying the early urban agglomerations of the Levant, Anatolia and Iraq have often cited highland Turkey as a likely source of raw materials such as metal, minerals and wood, critical to the populations in these relatively poorer environments (Muhly, 1973, aConservation Analytical Laboratory, Smithsonian Institution, Washington, D.C. 20560, U.S.A. bFaculty of Arts and Sciences, Bogaziyi University, Istanbul, Turkey. 'National Institute of Standards and Technology, Gaithersburg, MD 20899, U.S.A. (Deceased). "The Corning Museum of Glass, Corning, NY 14830, U.S.A. 541 0305--4403/91 /050541 +37 $03 .00/0 © 1991 Academic Press Limited Rakow Research Library, The Corning Museum of Glass - http://www.cmog.org Yener, K. A., et al. "Stable Lead Isotope Studies of Central Taurus Ore Sources and Related Artifacts from Eastern Mediterranean Chalcolithic and Bronze Age Sites." Journal of Archaeological Science, v. 18, no. 5 (Sept. 1991), pp. 541-577. © Academic Press, Ltd. 542 K. A. YENER ET AL. 1976; Charles, 1985; Moorey, 1985). This article will present thecharacterization ofmetallic ore sources within the central area of the Taurus mountains in Turkey through the determination ofelemental concentrations and lead isotope ratios. Ores from other source zones in Turkey will be similarly analysed and reported in subsequent papers. Artifacts belonging to the late Chalcolithic through the Bronze Age, which correlate with the Taurus sources, will also be discussed. Theapplication ofmultivariate statistics onthe isotopic data has enabled an assessment of the degree to which the Taurus ore sources can be discrimi nated from other ore sources throughout the Eastern Mediterranean through lead isotope ratio measurement, and an evaluation of the degree to which such data might provide eventual assessment of intra-site metal distribution patterns and large scale exchange processes, when more comprehensive source and artifact data are considered (Figure 1). The Taurus data base at our disposal stems from ores and slag samples from surveys in the years 1983-8 of the Central Taurus area for which data are included in this paper. In addition to this, 49 artifact samples with isotopic ratios consistent with well-defined Taurus ore sources are reported here, as well as 34 additional artifacts that have isotope ratios similar to Taurus ores for which only a few specimens have been analysed. They were extracted from an accumulated data base of isotopic measurements made on approximately 1000 specimens of Turkish, Greek, Cypriot, Caucasian, Syrian, Mesopotamian, Egyptian and Iranian ores and artifacts obtained by combining some 250, as yet unpublished measurements made in the Smithsonian-National Institute of Standards and Technology collaboration with the accumulated data in the published literature. A number of procedures were used to separate the Central Taurus source specimens into isotopically consistent groups, including the calculation ofordered isotopic similarity matrices, the generation of clustering dendrograms and correlation plots and the calcu lation ofmultivariate probabilities ofspecimens belonging to groups (Sayre, 1975; Barnes et at., 1988). When a group ofadequate size for statistical characterization was formed, the multivariate probabilities that other geological or archaeological specimens might belong to this group were calculated, with and without the Hotelling's T correction for small sample sizes. A surprising diversity oflead isotope ratios characterized the ores and slags taken from the Central Taurus region. Sufficient data are now in hand to define, reason ably well, four source areas with consistent ratios. These have been designated Taurus lA, Taurus lB, Taurus 2A, and Taurus 2B. Two specimens from the site ofEsendemirtepe had unique ratios similar to each other and four additional specimens of ores and a slag specimen were neither consistent with these data sets nor with each other. A map of the region showing sites from which specimens were obtained is shown in Figure 2. Each specimen has been given a technical examination. The examination usually included both compositional analysis by atomic absorption spectrometry and lead iso tope ratios by means of mass spectrometry. In some instances, samples were analysed by means of the scanning electron microscope (SEM), including X-ray emission measure ment, and by X-ray diffraction. Overall visual examination was made with a binocular microscope. Some of the ores were experimentally smelted (Ozbal & Ibar, 1990). The technical examination ofartifacts and ores was initially undertaken by K. Aslihan Yener, then with Bogazi<,;i University, Istanbul, and Hadi Ozbal, who did all the elemental analysis ofthe samples in the Chemistry Department ofthe same University. The isotopic measurements were carried out at the National Institute of Standards and Technology (NIST, formerly the National Bureau of Standards) by Emile Joel of the Conservation Analytical Laboratory of the Smithsonian Institution working with 1. L. Barnes of the Center for Analytical Chemistry at NIST. Edward V. Sayre of the Conservation Analyti cal Laboratory ofthe Smithsonian Institution collaborated with K. Aslihan Yener on the statistical analyses ofthese data. Before the inception ofthe Turkish ore project, R. J. Brill Rakow Research Library, The Corning Museum of Glass - http://www.cmog.org Yener, K. A., et al. "Stable Lead Isotope Studies of Central Taurus Ore Sources and Related Artifacts from Eastern Mediterranean Chalcolithic and Bronze Age Sites." Journal of Archaeological Science, v. 18, no. 5 (Sept. 1991), pp. 541-577. © Academic Press, Ltd. en ~ l'to l'tTl tTl o;1> -oen o>-l '"0 tTl en >-l oc:::: tTl -en Z >-l c:::: i'::l ~ ~ Vl Figure I. Map of relevant Eastern Mediterranean archaeological sites. W"'" Rakow Research Library, The Corning Museum of Glass - http://www.cmog.org Yener, K. A., et al. "Stable Lead Isotope Studies of Central Taurus Ore Sources and Related Artifacts from Eastern Mediterranean Chalcolithic and Bronze Age Sites." Journal of Archaeological Science, v. 18, no. 5 (Sept. 1991), pp. 541-577. © Academic Press, Ltd. 544 K. A. YENER ET AL. of the Corning Museum of Glass and 1. L. Barnes ofNISTwere collaborating on a study of lead isotope ratios of ores and objects from the Near East, some of the data of which have been incorporated into this study. The Lead Isotope and Elemental Analyses A sizeable number of chemical analyses, lead isotope analyses, and other laboratory studies have been carried out on Mesopotamian, Aegean, Anatolian, Syrian and other Near Eastern copper, bronze, lead and silver objects. Atomic absorption spectrometry was used to determine both major and trace elemental components. However, these data were used only to characterize the deposits and the artifacts in terms of their basic compositions because, in most instances, it was not possible to obtain samples free of corrosion products and surface contamination, which might have grossly altered the trace component levels. Very few earlier analyses of prehistoric silver metal objects or of silver ores in Turkey have been published. The use of isotope ratios of lead to characterize sources and objects depends upon the fact that lead ores occurring in different mining regions differ from one another in their isotopic