ICP-AES comparative study of some Late Bronze Age hoards: Evidence for low impurity bronzes in the Eastern Alps

The chemical composition of ingots from eleven hoards in Slovenia and from one in Austria (the Styria region) from the Late Bronze Age were determined using the ICP-AES method and the total impurities compared. One hundred and twelve plano-convex copper ingots from the earlier LBA phase (12th–11th century BC or Ha A period) revealed, in analogy with contemporary bronzes also analysed in our previous works, prevailing low concentrations of arsenic, antimony and nickel not exceeding 2%, with arsenic as the dominant impurity element. Conversely, in the later LBA phase (11th–10th century BC or Ha B period) totals of the same elements with cobalt included extend from 0.5% to almost 70%, with antimony as the dominant impurity element. The typical high concentration levels of impurities suggested that Fahlore deposits were used for smelting copper in the Ha B period, while chalcopyrite and other types of copper ores having low impurities were used in the earlier Ha A period. Both are typical of Eastern Alpine ore deposits.