Laser-based analytical methods for provenance studies of historical stone materials
Context
Understanding the provenance of construction materials is a key aspect in the study, conservation and restoration of large historical monuments. In the case of granite-built structures, identifying the original quarry sources can provide valuable insights into construction logistics, material selection criteria and long-term conservation strategies. The Aqueduct of Segovia represents an exceptional case due to its scale, historical relevance and the complexity of its stone supply chain.
Experimental approach
The group has conducted extensive laboratory analyses on granite samples collected from candidate quarry sites. These studies are based on laser-based analytical techniques applied under controlled conditions to ensure high data quality and reproducibility. The experimental campaign has generated hundreds of thousands of spectral measurements, capturing the intrinsic compositional variability of the different quarry sources.
Data analysis and modelling
Using this large spectral dataset, advanced multivariate analysis techniques have been applied to develop a classification and attribution model capable of associating unknown granite samples with their most likely quarry of origin. The resulting model demonstrates that granite from different quarry sources can be discriminated based on their spectral signatures, that intra-quarry variability can be statistically characterized, and that unknown samples can be assigned to candidate quarry sources with a high degree of confidence.
Relevance and next steps
These results establish a solid analytical foundation for future work, including the potential extension of the methodology to in-situ studies. Beyond the specific case of the Aqueduct of Segovia, the developed approach is directly transferable to other heritage structures built with granitic materials, offering a non-destructive pathway to provenance studies based on large-scale spectral data analysis.
Status
Ongoing. To date, the work has focused on laboratory-based studies using reference samples from granite quarries believed to have supplied material for the construction of the aqueduct. No in-situ measurements on the monument have yet been carried out.