Stone-working and the earliest steel in Iberia: Scientific analyses and experimental replications of final bronze age stelae and tools

Abstract

The south-western Iberian stelae from the Final Bronze Age (FBA) and Early Iron Age (EIA) have long been the centre of archaeological interest. These monuments show representations of human and animal figures, objects such as weapons, ornaments and chariots. Moreover, they provide insights into prehistoric stone working and sculpting techniques. On the downside, petrological studies of the rocks and consequent reflections on suitable tools are still the exception. Due to the lack of analysis and technological studies, this research will put emphasis on a multidisciplinary approach involving petrographic and metallurgic analyses, complemented by experimental archaeology.Firstly, an accurate lithological determination of stelae from Capilla (Spain) has been established with petrographic methods. According to the results, two slabs for replications of stelae were obtained from the identified mono-mineral quartz-sandstone (“quartzite”) outcrop. The experiment involved the trial of chisels made from all expedient materials that were available in the FBA-EIA by a professional stonemason. Considering that such extremely hard rocks require robust tools for carving, a long ignored iron chisel from the FBA site of Rocha do Vigio (Portugal) was studied with metallography and exposed heterogeneous, however surprisingly high-carbon steel. The analysed rocks are amongst the hardest that can be used for sculpting, and in the course of the experiment, bronze and lithic tools could be discarded. The only tool that showed an effect was the replication of the steel chisel from Rocha do Vigio with a hardened edge. The distinct work traces were compared to the original monuments. We hypothesize that the production of carbon steel as well as its hardening were possibly already known at the FBA-EIA transition in Iberia. Hence, only the access to iron technology allowed for the making of stelae from the lithotypes that were frequently used in the Zújar basin around the municipality of Capilla.