Tainted ores and the rise of tin bronzes in Eurasia, c. 6500 years ago.

Radivojevic, Miljana ; Rehren, Thilo ; Kuzmanovic-Cvetkovic, Julka 等

[ILLUSTRATION OMITTED]

Introduction

From their earliest appearance in the third millennium BC to their widespread adoption during the second millennium BC, tin bronzes had a significant impact on Bronze Age societies in Eurasia, including major changes in the economic, political and social lives of consumer communities (e.g. Harding 2000; Anthony 2007; Kuz'mina 2008). Bronze is an alloy of copper and other metals with copper as the major component. Tin is the most common alloying agent but other bronzes may incorporate arsenic, aluminium, silicon or phosphorus (Caron et al. 2004). To avoid ambiguity it has become common practice in archaeology to call the alloy of copper with tin 'tin bronze' and the alloy of copper with arsenic 'arsenical copper'.

Extensive scholarship has been devoted to the 'tin question' in pursuit of the sources of tin, the evidence for its production and the trade routes by which it travelled across the Old World (Muhly 1973; Pigott 1999; Yener 2000; Giumlia-Mair & Lo Schiavo 2003). The earliest known tin bronze artefacts, mostly pins or flat axes, have been discovered in Mesopotamia and Anatolia, and date to the early third millennium BC (Stech & Pigott 1986; Weeks 1999; Begemann et al. 2003; Helwing 2009). These objects contain up to 10 weight per cent (wt%) tin, and this is commonly thought to be due to the intentional addition of tin ore (cassiterite, Sn[O.sub.2]) to copper ores (co-smelting) or copper metal (cementation) (e.g. Cleziou & Berthoud 1982). These areas of early tin bronze consumption, however, lack significant tin sources. A quest for the tin source in Anatolia prompted extensive research on archaeological, geological and textual evidence, and likely origins were announced and subsequently dismissed in heated academic debates (Muhly 1993; Yener et al. 1993). More recently, multiple cassiterite sources exploited during the Bronze Age have been identified in modern Iran, Afghanistan, Uzbekistan and Tajikistan (Weisgerber & Cierny 2002; Nezafati et al. 2006, 2011; Pigott 2011; Stollner et al. 2011).

Alongside the important issue of the sources is the question of how the early production of tin bronze fits into the traditional narrative of the evolution of Eurasian metallurgy. This narrative seeks to follow a relatively simple, unilinear model of the inception and development of metallurgy from a single region. It begins with copper minerals and the first working of native copper in the Neolithic, which led to small-scale copper smelting from oxidic ores in the Chalcolithic. By the end of this period and well into the Bronze Age, mixing of ores was practiced to produce arsenical copper, followed by the large-scale smelting of sulphidic copper ores. By the Middle to Late Bronze Age, pure copper was alloyed with tin metal to mass-produce tin bronze. Iron production eventually emerged by the end of the Late Bronze Age (e.g. Wertime 1964). While this narrative is sufficient for interpreting broader consumption patterns that did indeed evolve in this order, a higher-resolution regional perspective on metallurgical production and innovation modulates this established sequence considerably, as, for instance, in the Middle East (Thornton 2009), or in the Americas, where the evolutionary trajectory of metallurgy is entirely independent of its development in the Old World (Lechtman 1980; Ehrhardt 2009). Multiple origins must therefore be envisaged.

The hypothesis of a single origin for Eurasian metallurgy (most recently Roberts et al. 2009) has been challenged by the discovery of copper smelting evidence some 7000 years old at a location outside the Near East: Belovode, a Vinca culture settlement in eastern Serbia (Radivojevic et al. 2010). Here, smelting of metal continued for several centuries alongside substantial malachite bead production, exploiting multiple local copper sources. Compositional analyses indicate a clear distinction between the malachite deposits exploited for bead making and those for copper smelting. Pure green malachite was favoured for bead making, while black-and-green ores, a copper and manganese mineral paragenesis, were used for copper metal extraction. Such consistent selection indicates a good understanding of the technological properties of various raw materials. The manganese content in copper minerals, indicated by the black-and-green colour composite, had a decisive role in selecting the best copper source for making metal. The pure green bead minerals were, on the other hand, sought for the strong symbolism of their colour (cf. Bar-Yosef Mayer & Porat 2008). The colour dichotomy of the black-and-green ores used for smelting and of pure green minerals processed for bead making makes the former appear as stained or 'tainted' ores, which is how they are termed in our research.

[FIGURE 1 OMITTED]

Here we present analyses of a tin bronze foil, from the Vinca culture site of Plocnik in southern Serbia, that may have been used for wrapping a ceramic vessel (Figure lA). The site of Plocnik has been solely occupied by the Vinca culture, and no later cultural intrusions have, thus far, been documented (e.g. Sljivar et al. 2012). The tin bronze foil was excavated from an undisturbed context, on the floor of a dwelling structure next to a copper workshop (Sljivar & Kuzmanovic-Cvetkovic 2009; Sljivar et al. 2012: 33). It lay approximately lm from a fireplace, and was found among several late Vinca culture pottery vessels (Figure 2). This securely contextualised find comes from a single undisturbed occupation horizon that has been dated to c. 4650 BC (Boric 2009: 214). According to the field evidence, the date is a terminus ante quem for the Plocnik foil. The tin bronze foil from the site of Plocnik is therefore the earliest known tin bronze artefact anywhere.

Early tin bronzes in the Balkans: background

The Plocnik foil is not the only find of early tin bronze artefacts in the Balkans. Fourteen other early tin bronze artefacts were discovered during the last century, but these were either poorly dated or insufficiently contextualised beyond their broad 'Chalcolithic' assignation (Chernykh 1978; Ottaway 1979; Tasic 1982; Pernicka et al. 1993). A piece of copper-tin slag deposited in one of the burials in the late fifth millennium BC cemetery of Zengovarkony in Hungary (Glumac & Todd 1991) represents further evidence of tin use in this period; however, its context has been questioned (Pernicka et al. 1997). The Plocnik foil thus is the only securely dated artefact among the entire Balkan early tin bronze assemblage.

Twelve of the previously analysed Chalcolithic finds originate from Bulgarian sites (Ruse, Karanovo, Gradeshnica, Smjadovo, Zaminec and Bereketska Mogila), and two from Serbian sites (Gomolava and Lazareva Cave) (Figure 3). They consist of awls, rings, needles, borers and a rod and have tin concentrations from 1-10wt%, followed consistently by significant levels of lead, arsenic, nickel, cobalt, iron and gold (Table 1). Although the exact concentrations of these elements vary widely from sample to sample, they appear qualitatively similar, which suggests an origin from similar types of ores. They are typologically similar to contemporary copper finds, and some of them directly match counterparts in pure copper from the fifth millennium BC Balkans. All of the objects were discovered in multilayered sites within disturbed Chalcolithic occupations, except a ring from Ruse (ASM 10882) that is reported to come from a child's burial belonging to an undisturbed Chalcolithic horizon. The cultural and chronological attribution of these tin bronzes was tentatively assumed to be Chalcolithic on the basis of their distinctive composition, different from later bronzes, and their limited quantity (Chernykh 1978:81). Furthermore, no other tin bronze artefacts are known in the Balkans before the third and second millennia BC (Chernykh 1978; Schickler 1981; Pernicka et al. 1997; Pare 2000), making it very unlikely that these early finds are intrusions from later layers.

[FIGURE 2 OMITTED]

Results

Two artefacts were newly analysed for this study: the foil from Plocnik (no. 63) and the Gomolava ring (no. 212) (Figure 1B), previously studied by Ottaway (1979); our methodology is reported in the online supplementary material.

The Plocnik sample has on average 11.7wt% tin (Table 1), together with lead, nickel, and iron at levels of between one tenth and half of one per cent each. The Gomolava ring has only 8.5wt% tin, but significantly higher levels of lead, arsenic, antimony and nickel, all between a quarter of one per cent and one per cent. Sulphur and selenium concentrations are relatively high in both samples.

The high level of metallic iron in the Plocnik foil demonstrates that this is freshly smelted metal, not re-melted during alloying (Craddock & Meeks 1987), while the presence of significant levels of antimony and arsenic in Gomolava 212 is typical of copper smelted from fahlerz ores (or fahlores). Both objects have a completely homogenised structure (Figure 4), which for tin bronzes above 8wt% tin requires annealing temperatures in the range of 500-800[degrees]C (Scott 1991). The foil is fully recrystallised, with grain sizes of c. 0.2mm (Figure 5). A single annealing twin in the microstructure is probably a result of cold working and prolonged annealing, which left the foil soft enough to be wrapped around a (presumably) ceramic vessel.

The Gomolava ring has an incompletely recrystallised structure with much smaller grain size (c. 0.025mm) indicating several cycles of working and annealing (Figure 6). This is consistent with a high degree of cold reduction, estimated at between 60 and 80 per cent (Rostoker & Dvorak 1990) on the basis of elongated sulphur-rich inclusions. The incompletely recrystallised structure may indicate that the last annealing process before final working was not carried through to completion, leaving the metal in a work-hardened state, suitable for use as jewellery.

In summary, the samples consist of chemically complex copper metal rich in tin and a range of minor and trace elements. They were made using different working sequences, carefully adjusted to the different properties required by the two objects, and with considerably higher annealing temperatures than those used for pure copper. This demonstrates that the metal smiths understood clearly the specific properties and requirements of tin bronze, as opposed to the more commonly used copper.

[FIGURE 3 OMITTED]

Tin bronzes in the Balkans: comparative analysis

The Plocnik and Gomolava objects are similar in composition to 13 previously analysed early tin bronzes from Bulgaria and Serbia. Compared to contemporary Early and Middle Chalcolithic (EC/MC) Bulgarian copper artefacts, levels of iron, cobalt, nickel and arsenic are on average about one order of magnitude higher, and those of antimony and lead up to two orders of magnitude higher (Table 1). Such a trace element pattern is not found in later tin bronzes, and is unlikely to originate from the addition of tin metal or cassiterite to ordinary copper; most cassiterite deposits and the tin smelted from them are very low in these base metals. Instead, the trace element pattern indicates the use of other, more complex ores for the production of these objects.

[FIGURE 4 OMITTED]

The analyses fall into three groups (Table 1). Traditionally, copper with significant impurities of arsenic, antimony, silver and nickel is thought to originate from fahlore smelting (Otto & Witter 1952; Merkl 2010). Fahlore copper, however, does not normally contain more than a few tens of ppm tin. Instead, the tin in these early bronzes is thought to originate from stannite, [Cu.sub.2]FeSn[S.sub.4], a copper-tin mineral structurally similar to chalcopyrite, and visually a dark metallic grey like fahlore. The three compositional groups presumably originate from a copper ore containing varying amounts of fahlore and stannite, probably mixed with other metal-rich minerals. The association of primary copper deposits, such as chalcopyrite, with both stannite and fahlore is not uncommon in sulphidic ore bodies in tin-rich provinces (Ramdohr 1980: 549-62; see also online supplementary material), and tin deposits are widespread throughout the Balkans (Glumac & Todd 1991). Ore batches used as a charge in the smelting process, retrieved from such ore deposits, would inevitably vary in their relative proportions of chalcopyrite, stannite and fahlore, resulting in the variable composition of the alloys seen here. The high sulphur content in both of the samples that were studied microscopically further indicates the sulphidic nature of the primary ore source, even if the smelted charge may have been dominated by secondary minerals formed from these sulphides. Thus, the three groups are tentatively labelled stannite bronze, high-tin fahlore bronze and low-tin fahlore bronze, indicating the possible ore types that could have underpinned their production.

The next horizon of bronzes in Serbia, dated to the third millennium BC, is characterised by significant arsenic (As) content (on average c. 1wt%, and reaching up to 4wt%), alongside traces of tin (Sn) (<400 ppm at most, with one exception ofc. 2wt%) (Pernicka et al. 1993: 12, tab. 3). In Bulgaria, the fourth millennium BC sites yielded only arsenical copper, with significant arsenic content (average c. 1wt%, and reaching up to 8.4wt%), and almost no tin (<0.1wt% at most, with one exception of c. 2.3wt%). Third millennium BC metal production in Bulgaria was mainly concentrated around pure copper and arsenical copper, save for a few artefacts containing variable tin (between 0.8wt% and 15wt%), alongside considerable arsenic levels (>lwt%) in some examples (Chernykh 1978: 368-69). Tin bronzes enter more regular circulation during the second millennium BC in Bulgaria (Late Bronze Age), with average concentrations of tin and arsenic at c. 5wt% and c. 0.3wt% respectively (Pernicka et al. 1997: 155-56, tab. A1). These LBA tin bronzes from Bulgaria come from different sites to those considered here, except for the awl from Gradeshnica, where three other tin bronze artefacts dated to the second millennium BC have also been found. The composition of these three LBA tin bronzes (all of which are stray finds) differs from the Gradeshnica awl (ASM 10686): one is more likely to be brass than tin bronze, the second shows the composition of a cassiterite bronze, while the third has half as much arsenic, and almost an order of magnitude more iron and nickel levels than the tin bronze awl in Table 1 (Pernicka et al. 1993:156). Hence these LBA objects differ significantly from the tin bronze awl under consideration here.

[FIGURE 5 OMITTED]

In summary, the unique compositional pattern of the 15 tin bronzes (Table 1) differs significantly from that of later metal artefacts in Serbia and Bulgaria. It is therefore reasonable to assume a temporal as well as geographical and technological connection among the 15 early complex tin bronzes that supports their attribution to the fifth millennium BC.

Noteworthy is a group of 25 tin bronze artefacts (tools and decorative items), which is compositionally similar to the 15 tin bronze artefacts we discuss here (Govedarica et al. 1995: 275-77, tab. 1, clusters 1, 2, 7, 9 and 11). These were discovered in several sites in Croatia (Dalmatia) and Bosnia and Herzegovina, and dated to the Early Bronze Age (early second millennium BC in this part of the Balkans), thus showing no temporal or spatial connection to the Chalcolithic tin bronzes. They are, however, very likely indicating a regional source of such a complex copper-tin-bearing ore that was used for their making, and possibly exploited even earlier, in the fifth millennium BC, for producing earlier examples of complex tin bronzes.

[FIGURE 6 OMITTED]

Discussion

The Vinca culture tin bronzes from Plocnik and Gomolava were carefully made artefacts smelted from complex ores, and worked with a combination of techniques well suited for the desired function. Their shape implies that they were used for decorative purposes; visual appearance played a significant role in their use. The foil from Plocnik was left in a soft annealed state so that it could be wrapped around a ceramic vessel, while the ring from Gomolava was left in the work-hardened state. The annealing temperatures used were much higher than those required for annealing the pure copper that was the dominant metal of the time, and indicates an understanding of the particular properties and requirements of these tin bronzes.

The early tin bronzes share strong qualitative and quantitative similarities in their minor and trace element patterns, implying their origin from broadly similar complex tin-bearing copper ores. They form three compositional groups: stannite bronze, high-tin fahlore bronze and low-tin fahlore bronze. All three groups of artefacts probably had primary and secondary copper minerals present in the smelting charge, as well as other accessory base metal minerals. The large variability in detail yet similarity in principle of the compositions indicate that the groups possibly originated from a single deposit with variable stannite and fahlore contents in different ore batches, or from a few geologically very similar ore deposits. Further research, including lead isotope and trace element analyses, will be necessary to address this issue of provenance.

The smelting of stannite for early tin bronze artefacts has already been hypothesised by Charles (1978) and Wertime (1978). Stannite is present in the Bronze Age mines of Mushiston in Tajikistan (Weisgerber & Cierny 2002), Deh Hosein in Iran (Nezafati et al. 2006), the Bolkardag mining district in Turkey (Yener & Ozbal 1987), as well as in Iberia (Rovira & Montero 2003). It has a metallic grey lustre, similar to fahlore with which it is easily confused, with an olive-green tint, particularly when it is partly weathered and intergrown with secondary copper minerals. The overall appearance then is one of tainted, black-and-green ores.

The selection of a self-fluxing ore comprising green copper minerals intergrown with black manganese minerals (as opposed to the pure green minerals used for malachite beads), may have been a key feature of Vinca copper smelting at the turn of the fifth millennium BC (Radivojevic et al. 2010). Visual appearance was also decisive in recognising copper minerals rich in stannite and/or fahlore. Weisgerber and Cierny (2002: 184) remark on the macroscopic appearance of the tin-copper paragenesis in Mushiston, Tajikistan: '... Mushistonite [(Cu,Zn,Fe)Sn[(OH).sub.6]] ... is trapped in a white quartz ... (as) the [hydrated] tin ore ... (and) stains it as black spots ... in fine grained yellow-greenish masses'. The black-and-green lustre of complex copper-tin ores could have been recognised as a desirable feature for tin bronze making well into the third millennium BC.

Significant tin mineralisations exist in western Serbia at Mount Cer and Bukulja, and at several localities in eastern Serbia, Bosnia, Croatia, Hungary and Romania; these are part of the extensive copper-sulphide-rich deposits within the Tethyan-Eurasian metallogenic belt (Glumac & Todd 1991; Jankovic 1997). The proximity of Plocnik and Gomolava to these deposits is remarkable, whereas no similar deposits have been reported in Bulgaria, where most of the tin bronzes have been found.

The characteristic composition of the tin bronze foil from Plocnik supports the fifth millennium BC date assumed for the other early tin bronzes that share this composition. That assumption is further strengthened by the absence of compositionally similar objects from later layers, and by the hiatus of more than a millennium before cassiterite tin bronzes appear in the Balkans. This makes it unlikely that these objects are intrusions from later levels. It also suggests that the particular deposit(s) yielding these ores were either exhausted or, more likely, were not the active cultural and technological choice of the Balkan Early Bronze Age cultural groups. The disappearance of the complex tin bronzes coincides with the collapse of large cultural complexes in north-eastern Bulgaria and Thrace in the late fifth millennium BC (Todorova 1995; Weninger et al. 2009). This suggests that these tin bronzes were 'cultural alloys', their production dictated by culturally embedded desires and preferences (Hamilton 1991), and not opportunistically or haphazardly made.

What were the advantages of tin bronzes? The presence of major impurities such as tin, arsenic and antimony improved their material properties: they melted at lower temperatures than pure copper objects and were easier to cast (Northover 1989; Lechtman 1996). These impurities also gave the artefacts a bright yellow colour. Colour has been recognised as crucial in the use of tin bronzes as an alternative to gold in central Asia (Kaniuth 2007), and for the early appearance of brasses (copper-zinc alloys also yellow in colour) from the early third millennium BC (Thornton 2007).

Colour is particularly interesting in light of the world's earliest gold objects, dated to the mid fifth millennium BC and deposited in the cemetery of Varna in Bulgaria to display social prestige (Renfrew 1986; Higham et al. 2007). Similar artefacts have been discovered in several mid to late fifth millennium BC settlements in Bulgaria (Makkay 1991). The colour and social significance of gold can be related to the emergence of the early tin bronzes, and the opportunities the latter might have offered as an imitation of gold. Tin bronze production in the Balkans during the fifth millennium BC may not only be intimately connected to copper, but to gold as well. To the visual similarity of gold and tin bronze we may add the relatively limited production of both metals, which stands in stark contrast to the massive production of contemporary copper metal implements (c. 4.7 tonnes extant) (Chernykh 1978). Access to gold and tin bronzes may have been reserved only for highly ranked individuals, as indicated by the Varna cemetery; it could also explain why so few yellow metal artefacts were in circulation at the time.

The polymetallic (r) evolution of the fifth millennium BC

Our study provides archaeological and analytical evidence for the independent emergence of tin bronze production, from complex copper-tin ores, some 1500 years before the first tin bronze alloys of south-western Asia. They also preceded by almost half a millennium the earliest use of natural alloys of arsenical copper (Roberts et al. 2009). Thus the fifth millennium tin bronzes fundamentally challenge the established sequence of the evolution of metallurgy in western Eurasia.

The selection of ores for these natural alloys was probably facilitated by their black-and-green colouration, similar to the black-and-green manganese-rich copper minerals already exploited in the initial stages of copper metallurgy in the Balkans. Tin bronze production was thus initiated by smelting ores that macroscopically resembled those already used for copper extraction.

The application of specific working techniques implies that the Vinca smiths were aware of the particular material properties of this new metal. Moreover, the colour of the final products could have been a key feature in their demand, particularly since it developed in parallel with the rise of gold production in the area. Hence the fifth millennium tin bronzes from the Balkans might have been produced to imitate gold.

Copper, tin bronzes and gold are not the only metals used in the Balkans at this period. There is evidence of mid fifth millennium BC use of both lead and galena from the Vinca culture sites of Selevac, Opovo, Autoput and Donja Tuzla (Glumac & Todd 1987). In the wider Balkan region the use of silver is attested by the hoard of more than 100 silver artefacts from the Alepotrypa Cave in Greece, and dated to the mid fifth-early fourth millennia BC (Muhly 2002). The near-contemporary use of tin bronze, gold, lead/galena and, most likely, silver in addition to the dominant copper in the Balkans during the mid to late fifth millennium BC defies the conventional narrative of a slow unilinear evolution of metallurgy. Quite the reverse, the early trajectory of metallurgy in the Balkans emerges almost from the very beginning as polymetallic in nature.

This 'polymetallism' has hitherto been considered exceptional, supported only by the evidence for smelting polymetallic (copper) ores from the late fifth millennium BC Bulgarian sites of Dolnoslav and Chatalka (Ryndina et al. 1999). The 15 tin bronze artefacts presented here demonstrate that the use of complex copper-tin bearing ores was more common than has been supposed. The polymetallic character of early Balkan metallurgy does not appear to be driven by the need for functional metals, but by demand for desirable visual properties in the final products. Thus, the co-occurrence of three, or possibly four, different metals next to copper with distinctive material properties requiring specific working techniques follows one common principle: their visual appearance. The visual appeal of new metals has been suggested before as the driving force behind their introduction (Lechtman 1977; Smith 1981; Hosler 1994; Kaniuth 2007; Thornton 2007); this research takes the argument further back in time to the very early stages of metallurgy in Eurasia.

Balkan polymetallism may have evolved from the aesthetic preferences of the consumer elite at the time. The black-and-green ores that gave rise to the tin bronzes were not the only ones being experimented with in this period. Exploitation of the material properties of other metals such as silver or gold indicates that metalworkers were actively pursuing various technological solutions. Their emergence marks both a polytechnological and polymetallic horizon. Interestingly, these polytechnologies were not utilised for the active alloying of two metal components; that only appears half a millennium later with arsenical copper and c. 1500 years later in the case of tin bronzes. The absence of alloyed metals in these early stages of Eurasian metallurgy has been traditionally ascribed to a lack of technological skills, but the evidence presented here challenges that conventional narrative by showcasing the significant level of metal craftsmanship in the fifth millennium BC. The reluctance to produce alloyed metals may well have been rooted in cultural as well as technological choices, for instance in the demand for a specific colour rather than advantageous material properties.

The production of complex tin bronzes in the Balkans declined towards the end of the fifth millennium BC. Significantly, this coincided with the collapse of the gold-using cultures in Bulgaria. Explanation could be sought in population dynamics, which were a powerful mechanism for both the generation and decline of innovations in prehistoric societies (Henrich 2004; Powell et al. 2009). Tin bronzes only re-appeared some 1500 years later, based on cassiterite tin. This alloy was widely adopted across central and south-western Asia but in a different cultural climate, when its production, consumption and trade acted as one of the driving forces behind the intensification of the economic, social and political lives of Bronze Age communities across Eurasia.

Acknowledgements

We thank S.J. Shennan, B.W. Roberts, C.P. Thornton and V.C. Pigott for constructive comments, and Lj. Radivojevic, J. Pendic, S. Zivanovic and M. Milinkovic for assistance with the illustrations. The authors are grateful to D. Sljivar for his kind help and support and to E. Chernykh and E. Pernicka for fruitful discussions that improved this article. This research is part of MR's PhD project, funded by EPSRC jointly with the Freeport McMoRan Copper and Gold Foundation through the Institute for Archaeo-Metallurgical Studies (IAMS) in London.

References

ANTHONY, D.W. 2007. The horse, the wheel, and language: how Bronze-Age riders from the Eurasian steppes shaped the modern world. Princeton (NJ): Princeton University Press.

BAR-YOSEF MAYER, D.E. & N. PORAT. 2008. Green stone beads at the dawn of agriculture. Proceedings of the National Academy of Sciences of the USA 105: 8548-51.

BEGEMANN, F., S. SCHMITT-STRECKER & E. PERNICKA. 2003. On the composition and provenance of metal finds from Besiktepe (Troia), in A. Wagner, E. Pernicka & H.-P. Uerpmann (ed.) Troia and the Troad: scientific approaches: 173-201. Berlin: Springer.

BORIC, D. 2009. Absolute dating of metallurgical innovations in the Vinca culture of the Balkans, in T.L. Kienlin & B.W. Roberts (ed.) Metals and societies. Studies in honour of Barbara S. Ottaway: 191-245. Bonn: Dr. Rudolf Habelt.

CARON, R.N., R.G. BARTH & D.E. TYLER. 2004. Metallography and microstructures of copper and its alloys, in G. F. Vander Voort (ed.) Metallography and microstructures: 775-88. Cleveland (OH): ASM International.

CHARLES, J.A. 1978. The development of the usage of tin and tin-bronze: some problems, in A.D. Franklin, J.S. Olin & T.A. Wertime (ed.) The search for ancient tin: 25-32. Washington, D.C.: Smithsonian Institution Press.

CHERNYKH, E.N. 1978. Gornoe Delo i Metallurgiya v Drevneishei Bolgarii. Sofia: Bulgarian Academy of Sciences Press.

CLEZIOU, S. & T. BERTHOUD. 1982. Early tin in the Near East: a reassessment in the light of new evidence from Afghanistan. Expedition 25: 14-19.

CRADDOCK, P.T. & N.D. MEEKS. 1987. Iron in ancient copper. Archaeometry 29: 187-204.

EHRHARDT, K. 2009. Copper working technologies, contexts of use, and social complexity in the Eastern Woodlands of Native North America. Journal of WorldPrehistory 22: 213-35.

GIUMLIA-MAIR, A. & F. LOSCHIAVO (ed.). 2003. The problem of early tin (British Archaeological Reports international series 1199). Oxford: Archaeopress.

GLUMAC, P. & J. TODD. 1987. New evidence for the use of lead in prehistoric south-east Europe. Archeomaterials 2: 123-45.

-- 1991. Early metallurgy in southeast Europe: the evidence for production, in P. Glumac (ed.) Recent wends in archaeometallurgical research: 9-19. Philadelphia: University of Pennsylvania.

GOVEDARICA, B., E. PERNICKA & K.F. ROTTERSHOFER.

1995. Neue Metallanalysen ans dem Westbalkangebiet, in P. Petrovi4 & S. Duroekanovic (ed.) Ancient mining and metallurgy in southeast Europe: 265-79. Belgrade: Archaeological Institute Belgrade; Bor: Museum of Mining and Metallurgy Bor.

HAMILTON, E. 1991. Metallurgical analyses and the Bronze Age of Bohemia: or, are cultural alloys real? Areheomaterials 5: 75-89.

HARDING, A.E 2000. European societies in the Bronze Age. Cambridge: Cambridge University Press.

HELWING, B. 2009. Rethinking the Tin Mountains: patterns of usage and circulation of tin in greater Iron from the 4th to the 1st millennium BC. Turkiye Bilimer Akademisi Arkeoloji Dergisi 12: 209-21.

HENRICH, J. 2004. Demography and cultural evolution: how adaptive cultural processes can produce maladaptive losses, the Tasmanian case. American Antiquity 69: 197-214.

HIGHAM, T., J. CHAPMAN, B. GAYDARKSA, V. SLAVCHEV, N. HONCH, Y. YORDANOV & B. DIMITROVA. 2007. New perspectives on the Varna cemetery (Bulgaria)--AMS dates and social implications. Antiquity 81: 640-54.

HOSLER, D. 1994. The sounds and colors of power. Cambridge (MA): MIT Press.

JANKOVIC, S. 1997. The Carpatho-Balkanides and adjacent area. Mineralium Deposita 32: 426-33.

KANIUTH, K. 2007. The metallurgy of the Late Bronze Age Sapalli culture (southern Uzbekistan) and its implications for the 'tin question'. Iranica Antiqua 42: 23-40.

KUZ'MINA, E.E. 2008. The prehistory of the Silk Road. Philadelphia: University of Pennsylvania Press.

LECHTMAN, H. 1977. Style in technology--some early thoughts, in H. Lechtman & R.S. Merrill (ed.) Material culture: styles, organization and dynamics in technology: 3-20. St Paul (MN): West.

--1980. The central Andes: metallurgy without iron, in T.A. Wertime & J.D. Muhly (ed.) The coming of the age of iron: 267-334. New Haven (CT): Yale University Press.

--1996. Arsenic bronze: dirty copper or chosen alloy? A view from the Americas. Journal of Field Archaeology 23: 477-514.

MAKKAY, J. 1991. The most ancient gold and silver in central and south-east Europe, in J.-P. Mohen & C. Eluere (ed.) Decouverte du metal: 119-28. Paris: Picard.

MERKL, M.B. 2010. Bell Beaker metallurgy and the emergence of fahlore-copper use in Central Europe. Interdisciplinaria Archaeologica 1 : 19-27.

MUHLY, J.D. 1973. Copper and tin. New Haven: Connecticut Academy of Arts and Sciences.

--1993. Early Bronze Age tin and the Taurus. American Journal of Archaeology 97: 239-53.

--2002. Early metallurgy in Greece and Cyprus, in U. Yalcin (ed.) Anatolian metal II: 77-82. Bochum: Deutsches Bergbau-Museum.

NEZAFATI, N., E. PERNICKA & M. MOMENZADEH. 2006. Ancient tin: old question and a new answer. Antiquity 80. Available at: http://www.antiquity.ac.uldprojgall/nezafati308/ (accessed 5 June 2013).

--2011. Early tin-copper ore from Iran, a possible clue for the enigma of Bronze Age tin, in U. Yalcin (ed.) Anatolian metal V: 211-30. Bochum: Deutsches Bergbau-Museum.

NORTHOVER, J.P. 1989. Properties and use of arsenic-copper alloys, in A. Hauptmann, E. Pernicka & G.A. Wagner (ed.) OM World archaeometallurgy: 111-18. Bochum: Deutsches Bergbau-Museum.

OTTAWAY, B.S. 1979. Analysis of the earliest metal finds from Gomolava. Rad Vojvodanskih Muzeja (Novi Sad) 25: 53-59.

OTTO, H. & W. WITTER. 1952. Handbuch der altesten vorgeschichtlichen Metallurgie in Mitteleuropa. Leipzig: J.A. Barth.

PARE, C. 2000. Bronze and the Bronze Age, in C. Pare (ed.) Metals make the world go round: 1-38. Oxford: Oxbow.

PERNICKA, E., E BEGEMANN & S. SCHMITT-STRECKER. 1993. Eneolithic and Early Bronze Age copper artefacts from the Balkans and their relation to Serbian copper ores. Prahistorische Zeitschrift 68: 1-54.

PERNICKA, E., F. BEGEMANN, S. SCHMITT-STRECKER, H. TODOROVA & I. KULEFF. 1997. Prehistoric copper in Bulgaria. Its composition and provenance. Eurasia Antiqua 3:41-180.

PIGOTT, V.C. 1999. The development of metal production on the Iranian Plateau: an archaeometallurgical perspective, in V. C. Pigott (ed.) The archaeometallurgy of the Asian world: 73-106. Philadelphia: University of Pennsylvania Museum of Archaeology and Anthropology.

--2011. Sources of tin and the tin trade in southwest Asia: recent research and its relevance to current understanding, in P.P. Betancourr & S.C. Ferrence (ed.) Metallurgy: understanding how, learning why. Studies in honor of James D. Muhly: 273-91. Philadelphia (PA): INSTAP Academic Press.

POWELL, A., S. SHENNAN & M.G. THOMAS. 2009. Late Pleistocene demography and the appearance of modern human behavior. Science 324:1298-301.

RADIVOJEVIC, M., TH. REHREN, E. PERNICKA, D. SLJIVAR, M. BRAUNS & D. BORIC. 2010. On the origins of extractive metallurgy: new evidence from Europe. Journal of Archaeological Science 37: 2775-87.

RAMDOHR, P. 1980. The ore minerals and their intergrowths. Oxford: Pergamon.

RENFREW, C. 1986. Varna and the emergence of wealth in prehistoric Europe, in A. Appadurai (ed.) The social life of things: commodities in a cultural perspective: 141-68. Cambridge: Cambridge University Press.

ROBERTS, B.W., C.P. THORNTON & V.C. PIGOTT. 2009. Development of metallurgy in Eurasia. Antiquity 83: 1012-22.

ROSTOKER, W. & J.R. DVORAK. 1990. Interpretation of metallographic structures. San Diego (CA): Academic Press.

ROVIRA, S. & I. MONTERO. 2003. Natural tin-bronze alloy in Iberian Peninsula metallurgy: potentiality and reality, in A. Giumlia-Mair & E LoSchiavo (ed.) The problem of early tin (British Archaeological Reports international series 1199): 15-22. Oxford: Archaeopress.

RYNDINA, N., G. INDENBAUM & V. KOLOSOVA. 1999. Copper production from polymetallic sulphide ores in the northeastern Balkan Eneolithic culture. Journal of Archaeological Science 26: 1059-68.

SCHICKLER, H. 1981. 'Neolithische' Zinnbronzen, in H. Lorenz (ed.) Studien zur Bronzezeit: Festschrift fur Wilhelm Albert v. Brunn: 419-45. Mainz am Rhein: von Zabern.

SCOTT, D.A. 1991. Metallography and microstructure of ancient and historic metals. Marina del Rey (CA): Getty Conservation Institute.

SLJIVAR, D. & J. KUZMANOVIC-CVETKOVIC. 2009. Plocnik, archaeology and conservation. Diana (Belgrade) 13: 56-61.

SLJIVAR, D., J. KUZMANOVIC-CVETKOVIC & J. ZIVKOVIC. 2012. Belovode, Plocnik: on copper metallurgy in the Vinca culture. Zbornik Narodnog Muzca (Belgrade) 20: 27-46.

SMITH, C.S. 1981. On art, invention and technology, in C.S. Smith (ed.)A search for structum 325-31. Cambridge (MA): MIT Press.

STECH, T. & V.C. PIGOTT. 1986. The metals trade in southwest Asia in the third millennium BC. Iraq 48: 39-64.

STOLLNER, T., Z. SAMASCHEV, S. BERDENOV, J. CIERNY, M. DOLL, J. GARNER,

A. GONTSCHAROV, A. GORELIK, A. HAUPTMANN, H. RAINER, G.A. KUSCH, V. MERZ, T. RIESE, B. SIKORSKI & B. ZICKGRAF. 2011. Tin from Kazakhstan--steppe tin for the West? in U. Yalcin (ed.) Anatolian metal V: 231-51. Bochum: Deutsches Bergbau-Museum.

TASIC, N. 1982. Naselje bakarnog doba u istocnoj Srbiji. Zbornik radova Muzeja rudarstva i metalurgije u Boru (Serbia) 2: 19-36.

THORNTON, C.P. 2007. Of brass and bronze in prehistoric southwest Asia, in S. La Niece, D. Hook & 12. Craddock (ed.) Metals and mines: studies in archaeometallurgy: 123-35. London: Archetype.

--2009. The emergence of complex metallurgy on the Iranian Plateau: escaping the Levantine paradigm. Journal of World Prehistory 22:301-27.

TODOROVA, H. 1995. The Neolithic, Eneolithic and Transitional period in Bulgarian prehistory, in D.W. Bailey, I. Panayotov & S. Alexandrov (ed.) Prehistoric Bulgaria: 79-98. Madison (WI): Prehistory Press.

WEEKS, L. 1999. Lead isotope analyses from Tell Abraq, United Arab Emirates: new data regarding the 'tin problem' in Western Asia. Antiquity 73: 49-64.

WEISGERBER, G. & J. CIERNY. 2002. Tin for ancient Anatolia? in rd. Yalgin (ed.) Anatolian metal II: 179-87. Bochum: Deutsches Bergban-Museum.

WENINGER, B., C. LEE, E. ROHLING, O. BAR-YOSEF, U. BOHNER, M. BUDJA, M. BUNDSCHUH, A. FEURDEAN, H.G. GEBE, O. JORIS, J. LINS'YADTER, P. MAYEWSKI, T. MOHLENBRUCH, A. REINGRUBER, G. ROLLEFSON, D. SCHYLE, L. THISSEN, H. TODOROVA & C. ZIELHOFER. 2009. The impact of rapid climate change on prehistoric societies during the Holocene in the eastern Mediterranean. Documenta Praehistorica 36: 7-59.

WERTIME, T.A. 1964. Man's first encounters with metallurgy. Science 146: 1257-67.

--1978. The search for ancient tin: the geographic and historic boundaries, in A.D. Franklin, J.S. Olin & T.A. Wertime (ed.) The search for ancient tin: 1-6. Washington, D.C.: Smithsonian Institution Press.

YENER, K.A. 2000. The domestication of metals: the rise of complex metal industries in Anatolia. Leiden: Brill. YENER, K.A. & H. OZBAL 1987. Tin in the Turkish Taurus mountains: the Bolkardag mining district. Antiquity 61: 220-26.

YENER, K.A., P.B. VANDIVER & L. WILLIES. 1993. Reply to J.D. Muhly, 'Early Bronze Age tin and the Taurus'. American Journal of Archaeology 97: 255-64.

Received: 12 November 2012; Accepted: 24 January 2013; Revised: 12 February 2013

Supplementary material is provided online at http://antiquity.ac.uk/projgall/radivojevic338/

Miljana Radivojevic (1,2), Thilo Rehren (3), Julka Kuzmanovic-Cvetkovic (4), Marija Jovanovic (5) & J. Peter Northover (6)

(1) UCL Institute of Archaeology, 31-34 Gordon Square, London WC1H OPY, UK (Email: m.radivojevic@ucl.ac.uk)

(2) National Museum in Belgrade, Trg Republike la, 11 000 Belgrade, Serbia

(3) UCL Qatar, a partner of Hamad bin Khalifa University PO Box 25256, Doha, Qatar (Email: th.rehren@ucl.ac.uk)

(4) Museum of Toplica, Ratka PavloviLa 11, 18 400Prokuplje, Serbia (Email:jkcvet@yahoo.com)

(5) Museum of Vojvodina, Dunavska 35, 21 000 Novi Sad, Serbia (Email: mv.marijajovanovic@gmail.com)

(6) Department of Materials, University of Oxford, Begbroke Science Park, Oxford OX5 1PE UK (Email: peter, northover@materials.ox.ac, uk)

Table 1. Compositional data for early tin bronze artefacts from the
Balkans, given in wt%. Data for artefacts other than Plocnik (63)
and Gomolava (212) taken from Chernykh (1978: 112, 339-52) and
Pernicka et al. (1993: 10, tab. 3; 1997: 121-26, tab. A1).
Compositional patterns distinguished three separate groups, based
on the potential ores used for their production: predominant
stannite; fahlore with stannite (high-tin fahlore); and fahlore
with some stannite (low-tin fahlore). The bottom row represents an
average of 40 contemporary copper metal artefacts from the Early
(EC) and Middle Chalcolithic (MC), based on data from Pernicka et
al. (1993: 190, tab. 3; 1997: 147-48, tab. A1), demonstrating that
the trace element signature of the bronzes is unlikely to originate
from the copper.

Site of origin Sample label Object Cu wt% Sn wt%

Smjadovo HDM 2720 borer 90.5 8.6
Karanovo ASM 12043 ring 92.5 7.0
Bereketska Mogila ASM 12103 needle 92.9 6.0
Bereketska Mogila ASM 12105 awl 89.6 10.0
Karanovo ASM 12051 needle 92.1 7.0
Lazareva pecina HDM 1330 borer 98.0 7.1
Plocnik Plocnik 63 sheet 87.4 11.7

First group Average 91.8 8.2
 (stannite)

Gomolava Gomolava 212 ring 89.4 8.5
Ruse ASM 10853 awl 89.2 6.0
Ruse HDM 2046 borer 86.0 7.3
 (ASM 10875)
Ruse ASM 10863 borer 88.4 10.0
Ruse ASM 10882 ring 92.1 7.0

Second group Average 89.0 7.8
 (high-tin fahlore)

Bereketska Mogila ASM 12138 rod 96.8 1.0
Gradeshnica ASM 10686 awl 94.3 4.5
Zaminec HDM 2733 borer 95.9 3.1

Third group Average 95.8 2.9
 (low-tin fahlore)

Typical ECIMC 100 0.005
 (n=40)

Site of origin Sample label As wt% Fe wt% Co wt%

Smjadovo HDM 2720 0.34 0.44 0.01
Karanovo ASM 12043 0.20 0.05 0.02
Bereketska Mogila ASM 12103 0.35 0.70 0.012
Bereketska Mogila ASM 12105 0.01 0.30 0.04
Karanovo ASM 12051 0.07 0.20 0.01
Lazareva pecina HDM 1330 0.02 0.06 0.0003
Plocnik Plocnik 63 0.03 0.12 0.07

First group Average 0.15 0.27 0.02
 (stannite)

Gomolava Gomolava 212 0.35 0.005 0.025
Ruse ASM 10853 0.60 0.20 0.015
Ruse HDM 2046 0.35 0.31 0.016
 (ASM 10875)
Ruse ASM 10863 0.40 0.07 0.02
Ruse ASM 10882 0.50 0.07 0.04

Second group Average 0.44 0.13 0.023
 (high-tin fahlore)

Bereketska Mogila ASM 12138 0.06 0.02 nd
Gradeshnica ASM 10686 0.35 0.01 0.003
Zaminec HDM 2733 0.26 0.04 0.002

Third group Average 0.22 0.02 0.003
 (low-tin fahlore)

Typical ECIMC 0.04 0.04 0.001
 (n=40)

Site of origin Sample label Ni wt% Ag wt% Sb wt%

Smjadovo HDM 2720 0.02 0.016 0.020
Karanovo ASM 12043 0.15 0.004 0.005
Bereketska Mogila ASM 12103 0.02 0.002 0.010
Bereketska Mogila ASM 12105 0.06 0.002 nd
Karanovo ASM 12051 0.50 0.0003 nd
Lazareva pecina HDM 1330 0.004 0.007 0.013
Plocnik Plocnik 63 0.16 nd nd

First group Average 0.13 0.005 0.01
 (stannite)

Gomolava Gomolava 212 0.25 0.08 0.45
Ruse ASM 10853 0.20 0.04 0.20
Ruse HDM 2046 0.28 0.03 0.30
 (ASM 10875)
Ruse ASM 10863 0.40 0.03 0.50
Ruse ASM 10882 0.10 0.03 0.06

Second group Average 0.25 0.04 0.30
 (high-tin fahlore)

Bereketska Mogila ASM 12138 0.008 0.02 0.07
Gradeshnica ASM 10686 0.04 0.05 0.50
Zaminec HDM 2733 0.06 0.108 0.33

Third group Average 0.036 0.06 0.30
 (low-tin fahlore)

Typical ECIMC 0.01 0.04 0.01
 (n=40)

Site of origin Sample label An wt% Pb wt%

Smjadovo HDM 2720 0.002 0.05
Karanovo ASM 12043 0.001 0.02
Bereketska Mogila ASM 12103 0.003 0.005
Bereketska Mogila ASM 12105 0.003 0.004
Karanovo ASM 12051 0.003 0.15
Lazareva pecina HDM 1330 0.004 0.006
Plocnik Plocnik 63 0.016 0.40

First group Average 0.004 0.09
 (stannite)

Gomolava Gomolava 212 0.002 0.82
Ruse ASM 10853 0.001 3.5
Ruse HDM 2046 0.003 0.05
 (ASM 10875)
Ruse ASM 10863 0.030 0.18
Ruse ASM 10882 0.003 0.05

Second group Average 0.008 0.92
 (high-tin fahlore)

Bereketska Mogila ASM 12138 0.0029 2.0
Gradeshnica ASM 10686 0.0030 0.2
Zaminec HDM 2733 0.0014 0.14

Third group Average 0.002 0.78
 (low-tin fahlore)

Typical ECIMC 0.001 0.013
 (n=40)