Smelting and recycling evidences from the Late Bronze Age habitat site of Baiões (Viseu,Portugal)

Many aspects of bronze production during Late Bronze Age in Western Europe are so far unknown. In the present study selected artefact fragments and metallurgical debris, which include a slag fragment, from the emblematic Late Bronze Age habitat site of Castro da Senhora da Guia de Baiões (Viseu, Portugal) have been studied by optical microscopy, micro-EDXRF, SEM–EDS and XRD. Evidences were found for bronze production involving smelting and recycling. Compositional analysis showed that the artefacts are made of a bronze with 13 ± 3 wt.% Sn (average and one standard deviation) and a low impurity pattern, namely <0.1 wt.% Pb, being comparable with the composition of other bronzes from the same region (the Central Portuguese Beiras). This alloy is generally different from elsewhere Atlantic and Mediterranean bronzes, which show frequently slightly lower Sn contents and higher impurity patterns, namely Pb which is often present as an alloying element. The present study gives further support to early proposals suggesting the exploration of the Western Iberian tin resources during Late Bronze Age, and besides that, it indicates that metalworking and smelting could have been a commonplace activity requiring no specific facilities, being bronze produced at a domestic scale in this Western extreme of Europe.     

Technological continuity in Early Iron Age bronze metallurgy at the South-Western Iberian Peninsula – a sight from Castro dos Ratinhos

A collection of 54 bronze artefacts recovered from the inland settlement of Castro dos Ratinhos (Portugal) and belonging mainly to the 9th–8th centuries BC, was studied by the use of non-invasive and micro analytical techniques. EDXRF, Micro-EDXRF, SEM-EDS and Optical Microscopy were used to determine the alloy composition and to identify the different thermo mechanical operations applied in the production of the artefacts. Results show that the collection is entirely composed of good quality binary bronzes (with an average tin content of 10.1 ± 2.5%). Alloys with higher tin contents were kept in as-cast condition and used in the making of ornaments, while tools were often finished with forging and annealing operations. Despite the existence of some Orientalising features in the Castro dos Ratinhos, e.g. rectangular habitat structures, wheel-turned ware and amphorae, the exclusive use of binary alloys with a narrow range of tin content seems to be associated with an indigenous metallurgical tradition inherited from the Late Bronze Age. This may indicate that the Phoenician interaction within the inland indigenous communities was a slow and selective process, probably dependant on the social-economic and cultural development of local communities.     

Early Imports in the Late Bronze Age of South‐Western Iberia: The Bronze Ornaments of the Hypogea at Monte da Ramada 1 (Southern Portugal)

The composition and manufacture of Late Bronze Age metallic artefacts from funerary and domestic contexts of southern inland Portugal was studied. The prevailing trend comprises binary bronzes (10.3 ± 2.1 wt% Sn) showing deformed equiaxial grains, annealing twins and slip bands. The alloy composition is somewhat independent of artefact type, while the manufacture seems to rely on artefact function and the skilfulness of the metallurgist. The technological characteristics were linked with archaeological and chronological features, disclosing some artefacts of uncommon composition, such as low‐tin bronze bracelets (4.3–7.1 wt% Sn) associated with ornaments of exotic materials (glass and Egyptian faience beads, and also ostrich egg shell beads). The assemblage testifies to an archaic trade with the Mediterranean region before the establishment of the first Phoenician colonies on the southern Iberian coast.     

Technical Studies on the Bronze Age Metal Artefacts from the Graveyard of Deh Dumen,South‐Western Iran (Third Millennium BC)

During the excavations of the graveyard at the site of Deh Dumen in south‐western Iran, 15 graves from the Early/Middle Bronze Age were uncovered that contained a variety of metallic artefacts. This paper reports on the analysis of nine metal artefacts, including eight broken vessels and a decorative strip that covered the handle of a dagger. The ICP–MS results showed that the bodies of the vessels are made of tin bronze alloy with variable amounts of tin, while the internal piece of the base of one vessel is made from an arsenical copper alloy. Further, the metallic strip is a thin sheet manufactured with partially pure silver. Microanalytical and microstructural information yielded by SEM–EDS revealed elongated Cu–S inclusions and lead globules as various phases formed in bronze solid solution. This study presents some information about the transition from arsenical copper to bronze metallurgy in the third millennium bc in south‐western Iran.     

Fuel Efficiency of Ancient Copper Alloys: Theoretical Melting Thermodynamics of Copper,Tin and Arsenical Copper and Timber Conservation in the Bronze Age Levant*

The melting of pure or alloyed copper, tin and arsenical copper ingots or recycled objects was a drain on the timber and dung fuel resources of many cultures. This paper suggests formulae grounded in thermodynamic principles in an attempt to estimate the energy requirements necessary to melt copper alloys common to both Old and New World cultures, with the goal of identifying consumption and conservation patterns. It has been suggested that tin bronze metallurgy was first adopted in the Levant during the Early Bronze Age (EB) IV, at the onset of the Late Holocene climate episode (c.2300–2000 bc ), becoming the most desired alloy by the Middle Bronze Age (MB) II (2000–1530 bc ) due to the ease of melting tin. To test this hypothesis, the formulae are applied here to all published Levantine EB IV – MB II copper alloys. Fuel conservation rates are proposed based on the thermodynamic formulae. Tin bronze is demonstrably more fuel efficient than pure copper. Due to the inherent difficulties in predicting the behaviour of arsenical copper compounds, it is suggested that melting experiments with representative alloys are conducted to further test and refine these energy relationships.     

Middle Bronze Age Arsenical Copper Alloys in Southern Portugal

In the Iberian Peninsula, the copper metallurgy from the Chalcolithic to the Middle Bronze Age (MBA) was mostly characterized by low arsenic contents. A collection of 53 MBA artefacts from southern Portugal was analysed by micro‐EDXRF, optical microscopy, SEM–EDS and Vickers to investigate the metal composition and manufacture. No technological distinction was found between artefacts from domestic and funerary contexts, which were radiocarbon‐dated to 2000–1500 cal bc . The arsenic contents of almost 100 MBA artefacts from this region, including the above‐mentioned set, have a Gaussian distribution with a high average (3.9 wt% As). Possible explanations are discussed for this distinctive metallurgy at the south‐western end of the Iberian Peninsula.     

贵州银子坛墓地出土铜锡器的初步分析

为研究黔西地区铜器时代金属制作技术及水平,本文采用金相显微镜和扫描电镜,对贵州银子坛墓地出土13件铜器和2件锡器进行了金相观察和化学成分分析,发现中水银子坛墓地出土的战国到西汉时代的铜器,有红铜、锡青铜和铜锡铅合金多种材质,而锡器有纯锡器以及锡铅合金,合金配比已具有一定的水平。制作技术有铸造和锻造工艺,并能应用冷热加工技艺。本文对研究古夜郎地区金属器的制作技术有一定的价值。     

A Compositional and Microstructural Study of Eighth‐Century BC Bronzes from Moita Da Ladra (Tagus Estuary): How Did the Spread of the Phoenician Metallurgy Take Place in Western Iberia?

Metals from a votive deposit at Moita da Ladra (Tagus Estuary) dating to the eighth century bc were studied by micro‐EDXRF, optical microscopy and Vickers testing to investigate the adoption of Phoenician innovations by indigenous communities. Artefacts are made of bronze alloys with suitable tin contents (11.6 ± 2.3 wt%) and very low iron impurities (<0.05 wt%), and were often manufactured using the long post‐casting sequence. Comparisons with indigenous and Phoenician metallurgies from western Iberia revealed a conservative technology suggesting that the spread of Phoenician innovations was very slow. In this region, the adoption of a diversified copper‐based metallurgy and reduction furnaces only seems to occur during the Post‐Orientalizing Period, c. sixth to fourth centuries bc .     

EARLY BRONZE AGE TROJAN METAL SOURCES AND ANATOLIANS IN THE CYCLADES

Summary. New chemical analyses of EB II copper-alloy artefacts from Troy show that about seventy per cent are of high tin, low arsenic, bronze; the remaining Trojan objects are of arsenical copper but contain no more than 3 per cent of arsenic. Lead-isotope analyses suggest that at this time the Trojans made use of at least five different copper-ore deposits and that at least two of these were not in the immediate vicinity of Troy itself.
At this period tin bronze was unknown in the Early Helladic, Cycladic or Minoan cultures. Low-arsenic tin bronzes do however constitute sixty-nine per cent of the copper-alloy artefacts excavated at the fortified hilltop EC IIIA settlement at Kastri on Syros, but lead-isotope analyses show that the copper in these objects is derived from three different ore deposits which are different from those exploited by the early Cycladic peoples on Amorgos, Paros, Kythnos and Chalandriani on Syros. For Kastri the alloy types are closely similar to and the copper ore sources used are identical with those employed in Troy II; in addition there are good Anatolian parallels for some of the metal types occurring at Kastri. Taken together with evidence from the pottery, the architecture and the nature of the site it seems inescapable that Kastri was a short-lived settlement of Anatolians who lived, perhaps, in somewhat uneasy juxtaposition with their Cycladic neighbours. These Anatolians came most probably from Troy or the Troad since tin bronze was virtually unknown at this period elsewhere in Anatolia, and certainly not in Cilicia, except at the central Anatolian sites of Ahlatlibel, Alishar and Alaca Hüyük.     

Middle Bronze Age metallurgy in the Levant: evidence from the weapons of Byblos

This paper constitutes a synthesis of a technological investigation on copper base alloy weapons from Byblos. Most of the weapons are typical of the Middle Bronze Age in the Levant. Methods such as metallographic examination and chemical analyses by EDS were used to identify the different stages of the chaîne opératoire used in the making of these weapons. The results reveal precise information regarding the production of several types of weapons such as the type and performance of the moulds used for casting and the deformation process. Furthermore, these results highlight the contribution of economic and cultural factors in the choice of components in a copper base alloy recipe. Finally, the use of silver–copper brazes for joining copper base alloy objects is recorded for the first time for the period and region concerned.     

Rediscovering famous assemblages: A rare Bronze Age crucible from El Argar,Spain

A rare open shallow crucible from the British Museum collection, excavated at the Bronze Age site of El Argar in south-east Spain by Louis and Henri Siret, was studied using X-radiography and scanning electron microscopy. The crucible has relatively thick walls, a spout and a non-refractory fabric. It was used for melting copper alloys for various possible purposes, such as alloying, refining, recycling or before casting, at around 1100°C. Both arsenic and tin were detected in various places and concentrations in the analysed specimens. This crucible could have been used during the period of transition from arsenic-rich copper to tin bronzes in the El Argar culture, or used for the recycling of arsenic-rich copper artefacts being alloyed with tin to produce tin bronzes. This melting crucible is a rare example of its kind to have been investigated scientifically, as most crucibles from contemporary sites on the Iberian Peninsula are generally associated with smelting. This study has also crucially shed more light on the types of alloys and variety of activities undertaken during that transitional period between the use of arsenical copper and tin bronzes in this region.     

Bronze technology of the ancient megalithic communities in the Vidarbha region of India

Metallographic examination was carried out on forty-nine copper and bronze objects from five megalithic sites located in Vidarbha, India. The artifact assembly consists of horse ornaments, kitchenware, bangles, rings, small bells and the hilt of an iron dagger. Results show that the technology involved is characterized by the use of bronze alloys containing approximately 10% tin based on weight and the application of forging as a key method of fabrication. No deliberate addition of lead was observed. Arsenic was detected, but very rarely and only as an insignificant minor element. The consistent selection of such specific alloys indicates that the megalithic communities in this particular region had established a fully developed and standardized bronze tradition optimized for the production of forged items. Their advanced technological status was also noted in a special technique applied to two forged high-tin bronze bowls. Such a unique bronze tradition, dedicated to sheet metal technology, was most likely a practical choice made by these people to take advantage of the changing role of bronze. Specifically, with the introduction of iron, bronze seems to have become a more prestigious material that could serve as an indicator of the appearance of a more rigid socio-economic stratification within the megalithic communities of the Vidarbha region.     

明代铜镜科学考察

通过对部分明代铜镜的科学分析,了解到明代也使用过与战国汉唐成分相近的合金来铸镜;除了锡汞齐外,此时还使用了铅汞齐和铅锡汞齐来开镜或磨镜。     

The production of speiss (iron arsenide) during the Early Bronze Age in Iran

In this paper, analyses of some unusual slag samples from the prehistoric site of Tepe Hissar in northeastern Iran are presented. These slags are the remains of a five-thousand-year-old pyrotechnological process that produced speiss, a quasi-metallic material usually formed as an accidental by-product of copper or lead smelting. We argue that the “speiss slags” from Tepe Hissar suggest the intentional production of iron–arsenic alloy (“speiss”) in prehistory. Why the Tepe Hissar metalworkers produced speiss is a question that requires further investigation, but our preliminary assessment suggests that it was to provide arsenic as an alloying component for arsenical copper, the preferred copper alloy during much of the Early Bronze Age in Iran, and widely used across the ancient world. This recognition significantly advances our understanding of the early stages of metallurgy in the Old World.     

Massive storage in As Laias/O Castelo (Ourense,NW Spain) from the Late Bronze Age/Iron Age transition to the Roman period: a palaeoethnobotanical approach

The highest platforms of As Laias, a settlement located in northwest Iberia, were used for storage during the Iron Age and until the turn of the Era. In this time-span, the whole hilltop – the croa – was a walled enclosure mostly used for storage and due to recurrent fires affecting the settlement's terraces, abundant plant remains were preserved in overlying wattle and daub storage structures.     

The Composition and Microstructural Variation of the Bronze Age Metal Ornaments from Lower Silesia (South‐West Poland): Chemical Analytical and Archaeological Aspects

Metal ornaments from Únětice (Mierczyce, Tomice, Jordanów and Opatowice) and Urnfield culture (Szprotawa, ?arek and Wroc?aw ?erniki) sites in south‐west Poland are made of bronze of varying composition, with the exception of the early Bronze Age Przec?awice site, where the copper items are found in graves from stages III/IV. The combined XRF and electron microprobe study of 37 ornaments (mostly pins) shows that those excavated from Únětice culture graves usually consist of cored dendrites, plus a Sb‐rich phase in some. The copper objects from Przec?awice correspond in composition to the East Alpine Copper or to the Ösenring copper and were produced from fahlore. Those from the Urnfield culture sites consist of homogeneous bronze. The Únětice culture ornaments were produced with little control of the effect of varying bronze composition on its microstructure. The results of XRF analyses of heterogeneous metal artefacts vary depending on the proportion of phases in the analysed site, and should be combined with micrometre‐scale analytical data and microstructural information yielded by electron microprobe methods. The same refers to deeply weathered or corroded objects made of homogeneous metal, which contain irregularly dispersed decomposition products.     

Morphometry of Middle Bronze Age palstaves by Discrete Cosine Transform

The Discrete Cosine Transform (DCT) is a Fourier-related transform widely used in signal processing and well suited to the analysis of open outlines. This method was applied here to evaluate the discrimination power of the inner lateral rib for two palstave populations dating from the Middle Bronze Age, excavated in northwest France. A corpus of almost 400 palstaves (bronze axes) of the Breton and Norman types was processed, and compared to specimens found at Sermizelles in Burgundy. The procedure is robust and produces a discrimination in good agreement with the traditional typology. Besides the definition of a ‘standard’ shape for each population, the morphometrical approach allows shape disparity, which is generally inaccessible to the naked eye, to be visualised and quantified. Shape disparity indicates that, contrary to previous assumptions, the bronze axes from the Sermizelles hoards cannot be explained as an assortment of Breton and Norman palstaves alone. We believe that this approach is quick, reproducible, and generalisable enough to be applied to a wide variety of artefacts from different periods, in order to clarify their typology and even their origin.     

Association for Field Archaeology Members

Abstract

This article is dedicated to Ronald F. Tylecote

Archaeologists and historians of metallurgy have attempted to explain the gradual abandonment of arsenic bronze in favor of tin bronze in the ancient Old world by making comparisons between the mechanical properties of the two bronzes. These comparisons purport to show the superiority of copper-tin alloys over alloys of copper and arsenic, despite an absence of data on the physical properties of the copper-arsenic system. The study reported here presents the results of mechanical tests carried out on experimental samples of both types of bronze over a broad range of alloy compositions. Hardness, tensile strength, and elongation determinations were made on cold worked and hot worked (forged) material. Whereas tin bronzes can be work hardened more extensively than arsenic bronzes, the far greater ductility of arsenic bronze makes it a desirable alloy for the manufacture of thin metal sheet. The widespread use of low-arsenic copper-arsenic alloys in the Americas, especially in the Andean culture area, is attributable in part to the tradition there of sheet metal production in the elaboration of three-dimensional forms.     

Cairo to Cape: The Spread of Metallurgy Through Eastern and Southern Africa

This article traces the beginnings of metallurgy in the eastern half of the African continent, focusing on three regions: (1) Egypt and Nubia; (2) the Great Lakes region of Central and East Africa; and (3) southern Africa. Metallurgy was not practiced much beyond the Nile valley until the first millennium BC, when copper, bronze and iron metallurgy began in Ethiopia and Eritrea, and iron metallurgy in the Great Lakes region. The expansion of agricultural societies carried iron metallurgy south, reaching its southern limit in South Africa by c. 300 cal AD. Copper was also smelted in southern Africa, but its use was restricted to pendants, bracelets, wire and other items of jewelry. In stark contrast to the metallurgical sequence in the Nile Valley, there was no production of tin, lead, gold or silver in central or southern Africa before these regions were linked to the Islamic world system after c. 800 AD.     

渝东长江干流青铜文化的几个问题——兼论渝东与川东渠江流域青铜文化的关系

古代巴国的青铜文化,由于长期以来缺乏比较系统的实物资料而一直未能获得更多的研究。近年以来川渝地区以及三峡地区考古工作的全面开展,为巴国青铜文化的研究提供了资料和条件。但由于巴国历史与疆域变迁的复杂性,使巴国青铜文化的许多问题还有待于深入探讨。本文根据渝东长江干流的考古发现,结合相关历史