Combined neutron and synchrotron X-ray microprobe analysis: attempt to disclose 3600 years-old secrets of a unique bronze age metal artifact

摘要

Over the most recent years, micro-analytical facilities based on neutron beams as well as synchrotron X-ray radiation advanced to indispensable instruments in the context of investigating artwork and archaeological artifacts. Using a combined approach of neutron and X-ray micro-beam techniques we investigated a uniquely decorated flanged axe dated into the Early Bronze Age (2200-1600 BC). This axe found in Central Europe is in view of its very early dating and striking parallels to Greek objects one of the most important artifacts concerning the provenance of its particular decoration technique. Neutron tomography was employed to obtain a full three-dimensional structural analysis of the object. Complementary, X-ray microprobe investigations were used to produce two-dimensional chemical and crystallographic images with high spatial resolution. The analysis of the internal structural details of the historical object provides invaluable information regarding manufacturing techniques and material properties. Important insights were obtained for different steps of the object creation including the body casting, the smithing, and-most important-the unique damascening decoration. The compositional analysis and the chemical imaging yield crucial information about the provenance of the metallic raw materials used. The technical and structural peculiarities observed for the axe of Thun-Renzenbiihl reveal distinct differences as compared to Mediterranean objects. Additionally, the chemical analysis of the copper inlays used as part of the decoration point towards the usage of pure copper metal, again in contrast to the more 'exotic' copper-gold alloys employed in the Mediterranean damascening decorations. Contradictory to the widely accepted conception of a strong influence of Mediterranean cultures, the present findings point towards a considerable influence of Bronze Age Central Europe by cultures located in the Balkan Peninsula and Caucasus region.