Metallographic examination of Bronze Age copper

Abstract

One can characterize ancient metallic finds by means of an ‘internal typology’ established through metallographic and chemical examinations as well as by means of the ‘external typology’ which is commonly used by historical scientists. For instance, the metallographic examination of a Bronze Age lance head enables identification of the technology used, thus supplementing the external findings. Paying special attention to this approach is worthwhile when following the path of the production line from ore deposit and ore dressing to smelting and refining. During these steps the chemical composition as well as the structure of the metal and its inclusions are drastically changed. It has been firmly established that in the Alpine regions, during the late Bronze Age, ores consisting of copper-iron sulphides, mainly chalcopyrite, were used to produce copper. It is possible to trace the variations in the chemical composition of the Cu-Fe-S inclusions in the course of the copper production with the optical microscope and microprobe analyser. Archaeological remains, including slags, matte, black copper, and thefinal products, are investigated. When the results from such investigations are compared with known facts about the late Bronze Age copper production of Spain, Italy, and the Near East, the independent development of the Central-European copper technology becomes evident.