Isotopic metal compositions of Viking and medieval tin artifacts from Poland reveal expansive trade network

Abstract

The lack of historically known tin deposits in Poland requires that the source of tin metal in ancient artifacts must be derived from foreign sources. To identify these external sources in the Viking Period, a combination of Pb and Sn isotope compositions and trace element analyses on a group of tin and tin rich alloys from three settlements in Poland was conducted. The integration of the chemical techniques reveals several sources for the tin rich artifacts, where group: 1) possesses Pb isotope values that overlap the Europe array which possess the highest (+1.6 ‰) and lowest (−1.1 ‰) Sn isotope values coupled with elevated In concentrations 2) has Pb isotope values that overlap the Slovakian array which possess lower Sn isotope values (+0.1 ‰ to + 0.3 ‰) coupled with low In and Te concentrations 3) has a Pb isotope value that is radiogenic which possesses a high Sn isotope value (+1.1 ‰). Group 1 artifacts are split into two sources designated by the higher Sn isotope values from Cornwall and the lower Sn isotope values from Brittany and are found in the two coastal settlements. Group two artifacts match a Slovakian origin, while one artifact labeled in group three possesses an Anatolian source. Defining the tin rich artifact sources allows constraint of the tin sources for the mixed alloys like bronze and pewter. In this instance the tin isotope values fall within two sources defined by the tin metal artifacts, Brittany and Cornwall. The chemical approach presented here defines distal metal sources to reveal a geographically expansive interconnected tin trade network that was predominantly European, in Viking times through chemical analysis of ornaments, coins, and beads.