Non-ferrous metal of the Petrovka Culture of the Southern Trans-Urals and Middle Tobol region according to scanning electron microscopy data

Abstract

The article presents the results of analytical study of copper and bronze items of the 19th–18th c. BC Petrovka Culture based on scanning electron microscopy. The sample includes tools, ingots, weapons, and ornaments originating from the materials of settlements and burial grounds in the Southern Trans-Urals and Middle Tobol region (54 items). During the work, the surface of the products was visualized with a study of topology of distribution of the elemental composition and structure of the metal in secondary (SE) and back-scattered (BSE) electrons to identify the phase composition of the samples. The obtained results suggest that this period saw the beginning of the widespread development of covellite-chalcocite and fahlores with bornite, galena, and possibly rocks from the oxidation zones of pyrite deposits, along with the use of minerals from the upper part of the oxidation zone — malachite, azurite, and tenorite. Such innovative advances in mining technology resulted in significant improvements in casting and metal processing techniques. Copper ores enriched with arsenic minerals — arsenates and arsenides — were used in the charge when smelting metal, together with tin-containing ores. The sources of tin bronzes were deposits in Northern and Central Kazakhstan, where the ores are represented by both pure cassiterite and polymetallic associations with sulfides. The exchange of ingots and finished products made of Cu+Sn and Cu+Sn+As alloys developed rather intensively in the latitudinal, mainly western, direction.

Keywords

• southern trans-urals
• petrovka сulture
• bronze age
• scanning electron microscopy
• ancient metallurgy
• types of raw material sources