On the behavior of siderophilic trace elements during iron production

• Applicants: Dr. Michael Brauns; Professor Dr. Ernst Pernicka
• Subject Area: Prehistory and World Archaeology
• Term: from 2021 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 460542971

The primary goal is to extend the already established method of determining the provenance of iron using osmium isotopes by the chemical characterization of the ferrous metal. Within the scope of this project, a combination of methods with other siderophilic elements will be developed, which will achieve an even more robust determination of the origin of archaeological iron artifacts using (very) small samples. It is important to verify the theoretically expected behaviour (stability, volatility, contamination) of other siderophilic elements during the production chain of iron smelting in experiments and to demonstrate the applicability in an archaeological case study. Platinum group elements (PGEs) other than osmium should not be included. The extraction of PGEs from iron ores is complex, the contents are very low and the suitable basis for comparison is practically non-existent.Our research project will be carried out on an experimental study and an archaeological case study:1. analysis of the whole production chain from ore to the lump in three smelting experiments with different ores (set of samples of the Os-isotope data published in PlosOne, 30 samples)2. analysis of 4 archaeological iron objects of the Arabah region/IsraelOur approach shall be characterized by the fact that we use innovative and proven analytical methods (laser ablation on impregnated powder samples or direct ablation of metallic iron see e.g. (Shaheen et al. 2017)), which will provide us in the future with highly precise analytical data (all of the above mentioned trace and main elements) without great effort. This approach could also be used by other scientists in the same or similar way in the future. This would provide the basis for a larger and more complete data basis within the scope of this project, which would achieve a more secure classification of archaeological iron objects.The combination of the two methods - trace element analysis and Os-isotope analysis - offers several advantages: larger sample series of iron objects can be grouped together on this meadow with only little intervention in the objects themselves according to their chemical composition. Further more destructive analyses, slag inclusions or Os-isotope analyses, could then be performed on a smaller selection of material groups. In addition, characteristic trace elements supplement the osmium isotope with information on the possible deposit type, which makes it possible to further narrow down the assignment of isotope ratios to a specific deposit. This complementary method would be of particular importance for iron finds for which information on possible smelting sites and thus also smelting waste such as slags is missing.

• DFG Programme: Research Grants