Reusing stones in medieval churches: a multidisciplinary approach to San Martiño de Armental (NW Spain)

Abstract

This paper presents an interdisciplinary methodology to help better understand the evolution of the use and reuse of stone material in the construction sequence of historical buildings. A combination of petrological analyses, stratigraphic analyses of walls, geochemical characterisation and absolute dating of mortars using optically stimulated luminescence and radiocarbon dating, the study of written sources and photogrammetry is applied to the case study of San Martiño de Armental, a rural parish church from NW Iberia. Results reveal a much more complex history and evolution than previously thought for this church, with the discovery of the remains of a tenth century AD building still standing in some parts of the building. This first church was already made of reused ashlars from one or several unknown buildings. Later Romanesque and modern phases still reuse some of these ashlars while incorporating new stone material. All the stones and mortars of the church seem to have local origin, although there are differences in their composition depending on the construction phase they belong to. Basing on these results, we will discuss in the last part of the paper how the reuse of materials can become an interesting reflection of the different construction techniques used and the level of economic investment made by those who promoted the work.