A study sheds light on how and where copper processing took place in prehistoric times

06.03.2024

The Copper Age is a transition period in prehistory and falls between the lithic industries of the Neolithic Age and the metallurgy of the Bronze Age. This chronological succession of the Stone Age, Bronze Age, and Iron Age is based on the seemingly universal sequence of the materials used in the manufacturing of every day and warfare tools. But in the case of the Copper Age, the introduction of the metal tends to follow differentiated local patterns in different geographical areas. 

The study entitled, Lead isotopes of prehistoric copper tools define metallurgical phases in Late Neolithic and Eneolithic Italy (Gilberto Artioli, Ivana Angelini, Caterina Canovaro, Günther Kaufmann, and Igor Maria Villa), published in Scientific Reports was conducted by researchers at the University of Padua in collaboration with the Archaeological Museum of Alto Adige. The work analyzed over 50 metal objects by precisely reconstructing the oldest flows of copper objects in Italy and establishing the temporal sequence in the exploitation of different mining areas.

The work shows that copper was produced in well-defined areas, but that at the end of the 5th millennium and the beginning of the 4th millennium, as copper production could not be found in Italy, such objects made with copper came from the Balkans. Starting from 3500-3600 BC an explosion of copper production took place in Tuscany, which is consistent with previous studies that had analyzed the copper ax of Ötzi, the Similaun Man found on 19 September 1991 in the Ötztal Alps. That discovery found that the copper extraction in the area, which was previously thought to be of local origin, was southern Tuscany. 

In the South-Eastern Alps of Italy, copper production took place after 2800 BC, thus progressively expanding and reaching massive production during the second part of the 3rd millennium BC. Alpine production then continued extensively in the Bronze Age.

The reconstruction of the key stages in prehistoric copper production was achieved thanks to isotopic and chemical analyses on over 50 objects made available by numerous Italian and Austrian museums. 

Each copper deposit has a very specific geological age of mineralization. The lead isotope ratios are notes referring to the age of the deposit. During the metallurgical process, when the extraction of copper was derived from ores and incorporated into the metal into objects, the isotopic signal remained unchanged. Analyzing the traces of lead contained in the copper of the object, researchers were able to trace the same signal that exists in the geological deposit of origin. Furthermore, by combining isotopic and chemical information any ambiguity in the provenance of the material is resolved using geochemical tracers. An element of complexity is the attribution of objects to a precise chronology, especially when the artifacts do not come from recent stratigraphic excavations and the dating is done solely on a typological basis, which is sometimes debated.