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<\/a><\/p>\nThe plano-convex ingot from S\u00e4rdal, Halland, Sweden. Image credit: Sabatini et al., doi: 10.1016\/j.jasrep.2025.105312.<\/p>\n
The ancient ingot was found in the autumn of 2022 at the village of S\u00e4rdal along the west coast of Sweden.<\/p>\n
The artifact proved to be a so-called plano-convex ingot \u2014 the first of its kind ever found in the country.<\/p>\n
\u201cThe plano-convex ingots, often also called \u2018bun\u2019 ingots or \u2018casting cakes,\u2019 are common throughout the Bronze and Iron Age, but vary in size, shape, and composition,\u201d said University of Gothenburg researcher Serena Sabatini and colleagues.<\/p>\n
\u201cThey are round artifacts with a generally flat upper face or topside and a variously bulged convex bottom or underside.\u201d<\/p>\n
\u201cThey are manufactured by pouring the melted metal into a mould or in a shallow cavity in the ground.\u201d<\/p>\n
\u201cMost of those ingots have a \u2018bubbly\u2019 and rough upper face, confirming that the metal was poured in an open casting mould, while the underside is generally smooth as it was not in contact with air during production.\u201d<\/p>\n
\u201cBeing a relatively simple product, they are widely spread across Eurasia and have been used not only in prehistoric but also in historical times.\u201d<\/p>\n
The S\u00e4rdal ingot is 14-15.3 cm in diameter, around 2.5 cm thick, and weighs 1223.5 grams.<\/p>\n
The surface of the ingot shows significant traces of corrosion especially on the rougher surface of its upside.<\/p>\n
The overall shape, size, and weight of the ingot strongly suggested that it could be a Bronze Age find.<\/p>\n
\u201cInitially, we believed the S\u00e4rdal ingot to date back to the Bronze Age,\u201d the archaeologists said.<\/p>\n
\u201cHowever, as it was found alone and could not be dated by its archaeological context, we decided to run isotopic and chemical analyses to determine its composition and suggest a possible chronology.\u201d<\/p>\n
The analyses provided unexpected results as the ingot turned out to be made of a copper-zinc-tin-lead alloy that was typical of the Iron Age and later periods.<\/p>\n
\u201cOnce the results arrived, and thanks to the open character of the international scientific community of scholars working with archaeometallurgical issues in the past, we realized that the isotopic and elemental characteristics of the S\u00e4rdal ingot were very close to a group of artifacts from two possible hoards found in the I\u0142awa Lakeland region, in northeastern Poland,\u201d the researchers said.<\/p>\n
Studies from the Baltic regions, which were intensely networking with West Sweden and southern Scandinavia during the pre-Roman Iron Age, indicate that the alloy of the type from S\u00e4rdal and the I\u0142awa Lakeland was present in the area already during the second half of the 1st millennium BCE.<\/p>\n
\u201cWe propose therefore that the plano-convex ingot from Halland and the rod ingots from Poland can be both considered the outcome of maritime trade in metal connecting Scandinavia and the Baltic Sea to the Iberian Peninsula during the period corresponding to the Scandinavian pre-Roman Iron Age, following ancient routes in use since the Late Bronze Age,\u201d the authors concluded.<\/p>\n