TECHNOLOGY AND PROVENANCE OF A COLLECTION OF ISLAMIC COPPER‐BASED OBJECTS AS FOUND BY CHEMICAL AND LEAD ISOTOPE ANALYSIS*

Chemical and lead isotope analyses were utilized to determine the composition, technology and origin of a collection of Islamic copper‐based objects found in Jordan. The atomic absorption spectrometry results show that the objects were made of different types of copper‐base alloys that contain various amounts of zinc, tin and lead. The use of brass, highly leaded brass and quaternary alloys of Cu‐Zn‐Sn‐Pb in the manufacture of everyday, household objects strongly points to Islamic traditions. The lead isotope compositions of the objects match very well that of the copper ore mined from the Dolomite‐Limestone‐Shale unit of the Arabah copper mines.     

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.     

Late medieval copper alloying practices: a view from a Parisian workshop of the 14th century AD

161 late medieval copper-based day-to-day items have been analysed, mostly consisting of small artefacts such as dress fittings. The items were all recently excavated from a 14th century AD metallurgical workshop located in Paris. Eight well-defined copper alloys have been identified that refer to various constraints, the most important one being economics. According to the model proposed, most of the alloys were obtained by dilution of a fresh brass master alloy by scrap metal containing small amounts of zinc, tin and lead. Pure lead was added separately in relatively large quantities, with a limit of 6 wt% Pb marking the boundary between leaded and unleaded alloys. It has been found that the less the cost of the artefact, the more the fresh brass is diluted. For the medium-size castings such as cast vessels, alloys containing large quantities of lead or alloys rich in antimony were used. Such complex alloying strategy pertains more to a small industrial-like plant organisation rather than to craftsman activity, as further supported by a variety of archaeological and historical evidence.     

安徽南陵出土部分青铜器研究

安徽省南陵县是长江下游地区最早而且规模最大的冶炼中心之一,其古代矿冶遗址可上溯至西周晚期。本研究对南陵出土的不同年代和类别的青铜器样品进行了金相检测及合金成分定量分析。结果表明,只有容器存在铜铅二元合金和铜锡铅三元合金,但是热锻淬火的容器却不含铅,含锡量恰好位于适合该工艺操作并具有良好性能的区间。兵器、工具、车马饰均为铜锡二元合金,说明当时的工匠对于合金成分配比与性能的关系有明确的认识。越式鼎腹部样品具有热锻淬火马氏体组织,同样的金属结构还见于汉代铜锣等乐器、峡江地区战国中晚期青铜剑、江都大桥镇南朝青铜器窖藏出土的多件青铜容器,而镇江地区出土吴国青铜戈则具有铸造淬火组织,工艺稍有差别。这些器物中发现高锡青铜淬火组织不是偶然的,高锡青铜热锻淬火技术至少可以上溯至春秋战国时期,用以改善高锡青铜的机械性能。     

Metals,microanalysis and meaning: a study of metal objects excavated from the indigenous cemetery of El Chorro de Maíta,Cuba

This is the first publication reporting systematic analytical research conducted on archaeological metals from Cuba. The main focus of the study consists of beads and small metal objects excavated at the cemetery of El Chorro de Maíta, which comprises some of the richest funerary deposits so far recovered on the island. Some comparative samples from the nearby site of Alcalá were also investigated, with an emphasis made on the manufacture, composition and origins of the different alloys. The resulting picture is that members of the social elite of the indigenous Taíno peoples were buried with beads made of placer gold exploited locally, gold–copper–silver pendants brought from continental South America and, above all, brass lacetags from European clothing that were perceived as sacred metals. The archaeometallurgical approach offers fresh insight into the relationships between Europeans and Taínos, and the impact of colonization on the indigenous customs, values and social structures.     

Late horizon silver,copper, and tin from Machu Picchu,Peru

Analyses of silver–copper alloy artifacts from Machu Picchu show silver contents ranging from 24 to 81%. The tin present, ranging up to 3%, originated with the copper, perhaps from admixture of recycled bronze. The presence of 0.4–0.9% lead in the silver-rich phase indicates use of silver prepared by cupellation. All the objects had been forged after casting, some extensively. All have surface enhancement of the silver arising from depletion of the copper-rich phase. Some of the tin found at the site contains inclusions of hardhead (FeSn₂) and of a nickel–arsenic–copper compound. Forming trials with duplicate silver–copper alloys show that intermediate anneals at temperatures between 500 and 600 °C facilitate making thin sheet artifacts. Mechanical tests show that the most commonly used alloys, containing 25–30% silver, are particularly well adapted to forging because of their uniform work hardening during plastic deformation. Annealing of the laboratory-made alloys in air followed by boiling in salty weak acid creates a silver-rich surface layer comparable to that found in the artifacts. Depletion forms a dense silver surface on the alloy containing more silver than the eutectic composition, but a porous surface layer on the 25% silver alloys.     

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。     

山西定襄中霍墓地出土铜器的初步科学分析

中霍墓地出土青铜器是研究春秋晚期和战国早期青铜文化特征、制作技术以及探讨该时期中原和北方少数民族相互关系等学术问题的重要资料。为进一步揭示该墓地出土青铜器所包含的科学信息,对该墓地出土17件铜器的37个样品进行了科学分析检测。结果显示,这批青铜器的制作工艺以铸造为主,另外还有热锻、热锻后冷加工等;其合金成分有铜锡二元合金和铜锡铅三元合金两种,铜锡二元合金全部用于制作工具,铜锡铅三元合金用于制造容器。这显示中霍墓地铜器的合金成分和器物类型之间的关系明显,表明制作者已经能根据青铜器的用途而选择合适的制作材料。研究结果对研究中原和北方少数民族冶金术及在此基础上的文化交流有较大的指示性意义。     

ANGLO-SAXON COPPER ALLOYS FROM LECHLADE, GLOUCESTERSHIRE

Summary. A range of copper-alloy artefacts from the early Anglo-Saxon cemetery at Lechlade were analysed using X-ray fluorescence. There were few pure bronzes or brasses in the assemblage and most alloys contained significant amounts of zinc, tin and lead in variable ratios. In view of the current theory that supplies of new metals and ores were limited and Anglo-Saxon metalworkers normally used scrap metal, the compositions were used to assess the techniques of the craftsmen supplying this community. It is concluded that re-use of copper alloys was prevalent but that metals were selected quite carefully for particular applications, with regard to the metallurgical characteristics required.     

QUANTITATIVE ANALYSIS OF COPPER-TIN BRONZES BY MEANS OF GLOW DISCHARGE OPTICAL EMISSION SPECTROMETRY

Glow discharge optical emission spectrometry (GDOES) has been used for obtaining calibration curves for copper, tin, lead, silver, antimony, arsenic, zinc and iron from standards including copper-base alloys (Cu 61.33-99.95%) and from bronze Punic coins. The GDOES results were calibrated using atomic absorption spectroscopy with inductively coupled plasma atomization (ICPAAS) to analyse the standards and coins. For all these materials, the results show that via GDOES it is possible to obtain reliable and reproducible calibration curves for copper, tin, lead, zinc and iron with a linear behaviour as a function of the content. The quantitative GDOES and ICPAAS data for the coins have been also compared with those obtained via X-ray fluorescence (XRF) and it is shown that GDOES, ICPAAS and XRF agree well with one another considering that the bronze coins are inhomogeneous to some degree. As an example of GDOES analytical features, a depth concentration profile through a thin bronze patina is shown and briefly discussed.     

Traditions and transitions in Korean bronze technology

Metallurgical examination of Korean bronze artifacts shows that a technical tradition based on casting and use of leaded high-tin alloys was established in Korea at the early stages of bronze use. After the subsequent discovery of quenching methods that suppress formation of the brittle δ phase, new thermo-mechanical techniques were introduced between the 7th and 10th centuries AD. Lead-free alloys were used, and tin contents near that of the peritectic point in the Cu–Sn phase diagram were chosen. Leaded high tin alloys continued in use, but only in cast objects, and with significant composition variation. The unique conditions during the time of innovation suggest that the transition to new metallurgical techniques was gradually achieved through domestic technical innovation inspired by external influences.     

咸阳龚西战国秦墓出土铜壶制作工艺研究

咸阳龚西战国秦墓出土的青铜器为研究战国时期秦青铜容器的铸造技术提供了重要实物资料。本文对龚西战国晚期秦墓M8出土的两件铜壶,通过表面观察结合X光摄像考察其制作工艺痕迹,利用金相显微镜、扫描电镜能谱分析等手段开展成分及显微结构分析,揭示两件铜壶壶身及表面装饰的制作工艺、材质特征。结果显示,两件铜壶均为铸造,器底和铜环预先铸好后置于范中,与器身铸为一体。器身和器底均为铅锡青铜(铜锡铅三元合金),但成分有一定差异,镶嵌的装饰金属片为高铅青铜。铜壶的器底分铸工艺和高铅青铜镶嵌工艺为古代青铜器制作工艺研究提供了重要的新材料。     

云南云龙坡头出土铜斧的科学分析

为研究滇西特别是古哀牢地区的古代铜器制作技术,采用金相显微镜、扫描电镜能谱分析等实验方法,对滇西云龙县坡头村出土的11件铜斧进行分析与研究。结果表明:云龙铜斧材质以Cu-Sn二元合金为主,另有Cu-SnAs三元合金。普遍存在硫化物夹杂,铸造与锻造两种制作技术并存,以锻造为主。11件样品中均进行过冷加工。本研究对认识古哀牢地区铜器制作技术与该地区青铜文化有一定的价值。     

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.     

Archaeometallurgical study of the brass cases from the Akko 1 shipwreck

The Akko 1 shipwreck is the remains of an eastern Mediterranean brig built in the first quarter of the nineteenth century, discovered in Akko harbour, Israel. During the underwater excavations (2006–2008), 158 brass cases were found, mainly between midships and the aft extremity of the shipwreck. It is suggested that they were used for artillery quills. The aim of this investigation is to determine the composition, microstructure and properties of these brass cases in order to understand their manufacturing process and to propose their possible dating and manufacturing location, and to verify their use. An archaeometallurgical analysis of selected brass cases was performed, including optical microscopy, microhardness tests and SEM including EDS. The results show that the collection was made of brass containing about 30 wt% zinc. The uniform thickness and the microstructure of the cases indicate that all artifacts were basically produced of rolled sheets and the cases were hand-made using simple tools. The metallurgical investigation suggests that they were manufactured during the first half of the nineteenth century. Combined with the archaeological evidence and the historical background, this supports the assumption that Akko 1 was a naval auxiliary vessel which was in Akko harbour circa 1840.     

古铜镜“水银沁”表面形成机理的研究

对加工纯铜、黄铜、锡青铜和铸造高锡镜青铜样品的基体及“磨镜药”处理前后表面进行检测,发现在磨镜处理时,“磨镜药”中的Sn原子通过Hg的作用首先以置换方式扩散渗入铜材表面的α固溶体中,当Sn元素浓度达到饱和时,将首先在晶体缺陷处生成Cu41Sn11新相并逐渐长大,使表面形成“水银沁”富锡层。富锡层逐渐氧化生成致密的、显微晶态的SnO2膜。此即古铜镜“水银沁”表面的形成机理。     

北京延庆西屯墓地出土汉代铜器的科学分析

延庆西屯墓地出土的汉代铜器对于了解北京地区汉代铜器文化特征、制作技术以及与周边地区的相互关系,具有十分重要的意义。为进一步揭示该批铜器包含的科学信息,本文对其进行了科学分析检测。结果显示,西屯墓地出土铜器的材质以铜锡铅三元合金为主,仅两件铜盆检测为铜铅二元合金、一件铜带钩为铜锡铅砷四元合金,且三类材质的合金化程度较低。除铜镜外,铜器的合金成分与器物类型之间没有明显关系,可见其青铜技术逐步衰退。多数铜器为铸造而成,根据器物的需要,还在局部采用热锻、热锻后冷加工等加工方式,说明当时的工匠已经能够根据需要应用相关技术。     

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.     

Bronze production in Southwestern Iberian Peninsula: the Late Bronze Age metallurgical workshop from Entre Águas 5 (Portugal)

Archaeological works at Entre Águas 5 (Portugal) uncovered a seasonal LBA settlement with significant metallurgical remains (crucibles, moulds, prills and a tuyere) related to bronze production. Radiocarbon dating ascribes an occupation period (10th–9th century BC) previous to Phoenician establishment in Southwestern Iberia. In spite of the proliferation of metal artefacts during LBA, the production of bronze alloys is still poorly understood. An integrated analytical approach (EDXRF, optical microscopy, SEM–EDS, micro-EDXRF and Vickers microhardness) was used to characterise this metallurgy. Crucibles show immature slags with copious copper nodules, displaying variable tin content (c. 0–26 wt.%), low iron amount (<0.05 wt.%) and different cooling rates. Certain evidences point to direct reduction of oxide copper ores with cassiterite. Scorched moulds with residues of copper and tin indicate local casting of artefacts. Finished artefacts also recovered at the site have an analogous composition (bronze with ∼10 wt.% Sn and low amounts of Pb, As and Fe) typical of coeval metallurgy in SW Iberia. Some artefacts reveal a relationship between typology and composition or manufacture: a higher tin content for a golden coloured ring or absence of the final hammering for a bracelet. An uncommon gilded nail (gold foil c. 140 μm thick; 11.6 wt.% Ag; ∼1 wt.% Cu) attests the existence of evolved prestige typologies. This LBA settlement discloses a domestic metallurgy whose main features are typical in Iberian Peninsula. Finally, it should be emphasized that a collection as comprehensive and representative of a single workshop has rarely been studied, enabling a deeper understanding of the various operations involving the bronze production and manufacture of artefacts.