The potential of using scanning electron microscopy with an energy dispersive analyzer for the study of the Bronze Age metal: on the problem statement

In this paper, the chemical composition of tools and ingots of the Petrovka Culture of the Southern Trans-Urals and Middle Tobol region is characterized with identification of main recipes of the alloys using several analytical methods (spectral, X-ray fluorescence, and atomic emission spectrometry analyses carried out in the laboratories of the Institute of Archaeology of the Russian Academy of Sciences and the Institute of Inorganic Chemistry of the Si-berian Branch of the Russian Academy of Sciences). The complexes of the Petrovka Culture of the Sou-thern Trans-Urals have been dated by a set of AMS 14C dates to 19th–18th centuries BCE. Recently introduced in the scientific discourse 27 AMS 14C dates (settlement of Stepnoe and burial grounds of Stepnoe 1, 7 and 25) established an ear-lier interval of the Petrovka series — 2133–1631 BCE and point to the synchroneity of the cultures at the northern periphery of the Sintashta area in the local micro-region of the Southern Trans-Urals. The results of the analytical study of 106 metal tools and 70 ingots of the Petrovka Culture of the Southern Trans-Urals and south of Western Siberia are reported. The statistical processing of the analytical results with plotting correlation diagrams of Sn–As, Sn–Pb, As–Ag, As–Sb, and a frequency distribution histogram for the proportions of Sn allowed casting the metal into 4 metallurgical groups — pure copper and tin, arsenic-tin and arsenic bronzes. The first group subdivided into oxide and sulfidic samples. According to the geochemical peculiarity of the metal from the metal industry centers of Ustie 1, Kulevchi 3 and Shibaevo 1, several sources of oxide-carbonated ores were utilized for copper smelting — malachite and azurite-malachite deposits, while sulfidic chalcocite-covelline ores, and sometimes chalcopyrite-pyrite depositions, were added to the melt as a flux agent. The admixture of sulfides was carried out as an experiment and was not purposeful. Petrovka metallurgists supplied copper to the workshops of the Middle Tobol region — the sites of Ubagan 1, 2, 3 and Kamyshnoe 1, 2. The centers of the Petrovka Culture of the Southern Trans-Urals were domi-nated by the production of pure copper implements, including the metal smelted from the oxidized ore. To a lesser extent, low-alloyed bronze was used — Cu+Sn, Cu+Sn+As and Cu+As, whose feedstock was supplied by the kin-dred tribes of Central and Eastern Kazakhstan in the form of ingots and finished products along the eastern part of the Trans-Eurasian transport corridor of metal trade — over the Turgay trough and further along the extensive river system of the Tobol River and its tributaries. The highest concentration of tools of alloyed bronzes was recorded in the burial grounds of the Middle Tobol, which can be explained from the point of view of the prestige value of such goods and observance of special ceremonial practices.

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Metallographic study of non-ferrous metal products from the Maray 1 site of the Baitovo Cul-ture in the Lower Ishim River region

Tigeeva

2024

VAAE

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The article examines non-ferrous metal products from the Baitovo Culture materials of the Early Iron Age hillfort of Marai 1. This settlement is located in the forest-steppe of the Ishim River region of Western Siberia. The upper building hori-zon marks the settlement of the Baitovo Culture dating to the 4th–2nd centuries BC. Metallographic analysis of 28 items was carried out using the Axio Observer D1m microscope (Zeiss). As a result, eight technological schemes characteristic for the metalworking activities of the Baitovo population have been identified. The study shows that prevailing were smithing tech-nologies in different temperature regimes for the production of non-ferrous metal objects (16 specimens, 57.2 %). The pref-erence was given to hot forging in the red-heat regime at 600–800°C (7 specimens, 25 %), cold forging with annealing (5 specimens, 17.8 %), as well as incomplete hot forging at 300–500°C (3 specimens, 10.7 %). Casting without further refine-ment was recorded in the microstructures of arrowheads, ingots and splashes (9 specimens, 14.2 %). Casting, followed by a slight degree of deformation (20–30 %), was noted in three cases. This scheme correlates with the metalworking traditions of the Itkul and Krasnoozerskaya Cultures, and it was dominant on the territory of the Tobol-Ishim region during the Early Iron Age. Such a low percentage of items related to it could be explained by the absence in Marai 1 of large items cast in moulds needing further refinement (knives, celts, etc.). A microstructural study confirmed the use of pure oxidized copper by the craftsmen of the Baitovo Culture, with characteristic inclusions of Cu–Cu2O eutectic, associated with the Ural production centres. Arrowheads and an ingot made of pure oxidized copper were probably a direct import from the territory of the Itkul Culture. Low-alloy tin and arsenic bronzes, coming from the metal production centres of Kazakhstan and Altai, were also used to the same extent for production of some tools and jewellery. The correlation between the type of product, composition of raw materials and technology of its manufacture has been revealed, which is most clearly manifested in arrowheads and awls. The use of high temperatures and significant degrees of compression (80–90 %) has been recorded in a number of cases, resulting in the appearance of rejects. Cracks of hot brittleness, as well as of cold brittleness, occurred in the process of technological cycle, carried out with an excess of the tensile strength of the metal.

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The potential of using scanning electron microscopy with an energy dispersive analyzer for the study of the Bronze Age metal: on the problem statement

Cited by 3 publications

References 26 publications

Copper and Bronze Tools and Weapons of the Petrovka Culture of the Southern Trans-Urals and the Middle Tobol Basin: Alloys, Historical and Metallurgical Relations

Copper and Bronze Tools and Weapons of the Petrovka Culture of the Southern Trans-Urals and the Middle Tobol Basin: Alloys, Historical and Metallurgical Relations

Metal tools of the Petrovka Culture of the Southern Trans-Urals and Middle Tobol: chemical and metallurgical characteristics

Metallographic study of non-ferrous metal products from the Maray 1 site of the Baitovo Cul-ture in the Lower Ishim River region

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