From near or afar? Possibilities of archaeological evidence and geochemical analysis in the study of the provenance of artifacts in hoards of iron objects from the La Tène period
Abstract
Hoards of iron objects from the La Tène period are surprisingly numerous. About 100 of them are known from Central Europe alone (Kotýnek 2020, Fig. 1).
They are often considered ritual offerings, or a storehouse of material or property, but this cannot be proved, with some exceptions. It is not yet known whether the items in the individual examined hoards are of the same or different provenance or whether differences can be found between analogous items from hoards and from settlements.
The methods applied in previous research do not provide a satisfactory solution to these issues. The main issue in researching the provenance of iron objects is the properties of iron and the way it is processed.
The very process of smelting iron ore significantly changes its chemical composition, which makes it difficult to determine its origin on the basis of its chemical composition. To date, no methodology has been proposed to answer (1) whether the items in the individual hoards examined are of the same or different provenance, (2) to determine whether differences can be found between analogous items in hoards and settlement situations in order to identify the purpose of the hoard in an analyzable way, (3) verify that items deposited in hoards could only be manufactured for the purpose of depositing.
The proposed poster presents a methodology suitable for answering the still unresolved questions related to depots of iron objects in the La Tène period. The methodology applies an interdisciplinary approach combining archaeological and exact metallographic and geochemical methods.
An analysis of the content of osmium isotopes, the content of which in iron is not affected by smelting, can be used to study the provenance of iron (Brauns et al. 2013, p. 842, 847; 2020, p. 2). Due to its siderophilic nature, it can be studied in iron itself and is not dependent on the presence of slag inclusions, the research of which in finished objects can be problematic, because the process of production of the object reduces their number and size (Charlton 2015, p. 211).
Metallographic analysis of sections and analysis of sample composition were chosen as additional methods.