This paper presents a study on copper production and distribution in Lower Austria's southeastern region during the Late Bronze Age (c. 1350-800 BC), with the focal point being the chemistry and ...isotopic character of artifacts from a small copper mining site at Prigglitz-Gasteil on the Eastern Alps' easternmost fringe. Ores, casting cakes, and select objects from the Late Bronze Age mining site at Prigglitz-Gasteil, Lower-Austria, and within 15 km of its surroundings, were chemically and isotopically analysed using XRF, NAA, and MC-ICPMS. The importance of Prigglitz-Gasteil as a local mining and metal processing center is evaluated based on the produced data, and the distribution and sourcing of copper-producing materials found at the site are discussed. Special attention is paid to the mixing of scrap and source materials early in the metal production process. The most salient discussions focus on the variability of the chemistry and Pb isotopic ratios of the studied objects, which seem to constitute a multitude of source materials, unlike the pure chalcopyrite-source copper produced from the Prigglitz-Gasteil mine itself. The analytical data suggests that copper alloys were mainly imported from materials originating in the Slovakian Ore Mountains, which were subsequently mixed/recycled with relatively pure locally produced copper. The purity of the copper from Prigglitz-Gasteil was fortuitous in identifying imported copper that contained measurable amounts of Pb and other chemically distinct characteristics. The chaîne opératoire of metal production at the site is mentioned; however, it is clear that additional information on the region's geochemistry is required before any finite conclusions on the ore-to-metal production can be made.
During the later Bronze Age in Europe (c. 1500–800 BC), the archaeological visibility of the production and consumption of bronze increases substantially. Yet there remains a significant imbalance ...between the vast number of finished artefacts that survive and the evidence for where, how, and by whom they were produced. At the centre of these questions is the metal smith, who has been variously regarded in scholarship as nomadic, a reviled outsider, elite in status, a mediator of wealth, a shaman or a proto-scientist. In most cases, however, the social role of the smith is seen as central to the functioning of Bronze Age societies This paper provides a new cross-regional study that evaluates current theoretical paradigms in the light of empirical evidence. It does this through contextual analyses of metalworking traces, focussing on case studies primarily from Atlantic, Nordic, Urnfield and Balkan regions of Europe. Our work breaks down the production cycle into various practical steps, and the material evidence for each step is evaluated. This enables similarities and differences on the broader European scale to be identified and discussed. Through this, our aim is to better characterise the modes of participation in smithing and the identities of those involved, and consequently to improve our understanding of the material patterns related to smithing activities that occur archaeologically. These patterns range from discard or deposition at settlements, the construction of identity in mortuary practice, technological choices in alloy design and treatment, and the quality of finished metalwork objects. Concerning the question of the single smith, it is argued that the material evidence in many regions indicates that metalworking was more broadly embedded in society; this might be through cross-craft interaction, the location of metalworking activities, and the reuse of casting debris and moulds. We argue that crafting metal was a commonplace and socially visible activity, which was in many regions a venue for enhancing social integration and stability.
This paper analyses 20 Late Bronze Age (ca 1080–800 BC) copper alloy objects to discern their manufacture and the skills of local craftsmen. Several tools and jewellery were studied that originated ...from a bronze workshop located immediately next to the Prigglitz-Gasteil copper ore mining site and several contemporaneous sites in the surrounding area. The samples were studied with optical microscopy (microstructurally), and SEM-EDXS and XRF (chemical analyses). Our analyses are part of a larger study and suggest that the Prigglitz region’s bronze production was not standardized. Particular alloys do not seem to have been chosen for object types or due to their intended use-function. Notably, approximately 20% of the objects contain unalloyed copper inclusions, which are most likely a result of the incomplete mixing of scrap metals and alloys during their production.
This study revaluates reported cases of prehistoric As-Cu objects with ‘silvery surfaces’, which are usually interpreted as the result of inverse segregation. Further possible explanations for such ...surfaces, such as an arsenic-rich α-solid solution, cementation, or post-depositional precipitation, are discussed. The segregation of arsenic was studied in As-Cu ingots produced in chill cast moulds at several compositions, which underwent surface treatment with an NaCl solution. The microstructure and surfaces of the As-Cu alloys were analysed using optical microscopy and SEM-EDXS. Special note of out-of-equilibrium As-Cu phases are discussed, as well as a comparison of inverse segregation to all other means of achieving surface silvering.
•Lists known instances of silvery surfaced prehistoric As-Cu objects.•Provides explanations for the possible causes of silvery surfaces such as: α-solid solution, cementation, or precipitation.•Provides microstructural and surface analyses of the As-Cu alloys via SEM-EDXS and optical microscopy.
The formation and crystal structure of the binary Cu3As phase have been re-investigated. Some physical properties were then measured on both single crystal and polycrystalline bulk. Cu3As melts ...congruently at 835 °C. At room temperature (RT), this compound has been found to crystallize in the hexagonal Cu3P prototype (hP24, P63cm) with lattice parameters: a = 7.1393(1) Å and c = 7.3113(1) Å, rather than in the anti HoH3-type (hP24, P–3c1) as indicated in literature. A small compositional range of 74.0–75.5 at.% Cu (26.0–24.5 at.% As) was found for samples synthesized at 300 and 400 °C; a corresponding slight understoichiometry is found in one out of the four Cu atomic sites, leading to the final refined composition Cu2.882(1)As. The present results disprove a change in the crystal structure above RT actually reported in the phase diagram (from γ’ to γ on heating). Instead, below RT, at T = 243 K (−30 °C), a first-order structural transition to a trigonal low-temperature superstructure, LT-Cu3−xAs (hP72, P–3c1) has been found. The LT polymorph is metrically related to the RT one, having the c lattice parameter three times larger: a = 7.110(2) Å and c = 21.879(4) Å. Both the high- and low-temperature polymorphs are characterized by the presence of a tridimensional (3D) uncommon and rigid Cu sublattice of the lonsdaleite type (Cu atoms tetrahedrally bonded), which remains almost unaffected by the structural change(s), and characteristic layers of triangular ‘Cu3As’-units (each hosting one As atom at the center, interconnected each other by sharing the three vertices). The first-order transition is then followed by an additional structural change when lowering the temperature, which induces doubling of also the lattice parameter a. Differential scanning calorimetry nicely detects the first low-temperature structural change occurring at T = 243 K, with an associated enthalpy difference, ΔH(TR), of approximately 2 J/g (0.53 kJ/mol). Low-temperature electrical resistivity shows a typical metallic behavior; clear anomalies are detected in correspondence to the solid-state transformations. The Seebeck coefficient, measured as a function of temperature, highlights a conduction of n-type. The temperature dependence of the magnetic susceptibility displays an overall constant diamagnetic response.
To improve our understanding of prehistoric casting methods and materials, simulations for copper arsenic (As-Cu) alloys with up to 15 wt.% As were calculated. Cooling curves and the secondary ...dendritic arm spacings (SDAS) for the alloy were plotted and calculated, respectively, under non-steady-state conditions with a time-stepping procedure for prehistoric mold materials (e.g., quartz sand, sandstone, terracotta, and steatite). The cooling and microstructure of the alloy was also simulated in iron molds for immediate comparison with as-cast microstructure. The microstructure and SDAS of the as-cast alloys were studied and measured in polished samples with a metallographic microscope. The purpose of this research was to improve our ability to retroactively evaluate the influence of mold materials on as-cast microstructures and determine their materials. This article focuses on As-Cu alloy microstructure and SDAS values, and also discusses the phenomenon of “inverse segregation” and its relation to cooling rate and As concentration.
•Cross-sections of archaeological broze objects were studied.•Dry open circuit potential measurements were also used.•Differences in hradness, compactness and metal crystallinity ...appear.•Electrochemical data are usable for dating purposes.
The application of a multiple-scan strategy to nanosamples taken from 18 cross-sections of Bronze Age arms and armour, as well as two Roman coins using two solid-state electrochemical techniques, the voltammetry of immobilized microparticles (VIMP) and open circuit potential measurements (OCP) is described. The voltammetric responses in contact with aqueous acetate buffer can be attributed to the reduction of cuprite with variable degree of compaction and crystallinity revealing significant differences in the gradient of such properties with depth. Such differences are also revealed by “dry” OCP measurements connecting points in the cross section near and separated from the corrosion layer. The voltammetric study of the metallographic samples of the bronze objects shows correlation with the age of the objects, respectively the period of their deposition. We discuss also (potential) influence of different factors on the VIMP and OCP measurements, such as deposition context (soil, water), chemical composition of the copper alloys, and microstructural features (as-cast, annealed, work-hardened), and how to overcome these issues.
This monograph provides an overview of all metal body armour from the European Bronze Age from a typo-chronological perspective but also in focusing on the manufacture and usage of such armour. This ...was enabled through the re-evaluation of central and eastern European finds in particular and their material analyses. The research history, distribution and chronology, as well as manufacture and use of helmets, greaves and cuirasses is discussed.
Die Publikation bietet erstmals einen Gesamtüberblick über metallene Schutzwaffen (Helme, Panzer, Beinschienen) der europäischen Bronzezeit. Typologie und Chronologie sowie Herstellung und Verwendung der Schutzwaffen werden erörtet. Dies wurde durch eine umfassende Neuaufnahme vor allem osteuropäischer Funde und durch zahlreiche Materialanalysen möglich.
This monograph provides an overview of all metal body armour from the European Bronze Age from a typo-chronological perspective but also in focusing on the manufacture and usage of such armour. This ...was enabled through the re-evaluation of central and eastern European finds in particular and their material analyses. The research history, distribution and chronology, as well as manufacture and use of helmets, greaves and cuirasses is discussed.
The chemical composition of ancient copper-based metal changes over time due to repetitive recycling and mixing of old metal. Prehistoric copper usually contains impurities from the copper ores ...themselves, and some have been used as evidence of anthropomorphically induced chemical change. Research into these changes has historically relied upon the assumption of element loss linearity, which is highly misleading and in fact varies with a multitude of factors. To illustrate the complexity of such losses for prehistoric alloys, we have selected arsenical bronze (Cu-As alloys) for study. The mass loss of several Cu-As-alloys under reducing atmosphere was measured by DTA/TGA. From our comparison of the experimental results to thermodynamic calculations and literature data, it was unclear whether weight losses were solely caused by the elemental loss of arsenic. However, a prolonged time temperature-cycling run demonstrated that mainly arsenic volatilizes; hence, the non-linear mass loss from the alloy can be directly attributed to arsenic.
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