OSL dating of mortars from constructive phases of the old chapel San Breixo de Ouvigo (NW Spain)

Abstract

Abstract The use of optically stimulated luminescence (OSL) dating on ancient mortars have provided increasing knowledge of the history of buildings in the last years. In this work, we apply OSL dating on mortars of a key building for the history of NW Spain: the old chapel of San Breixo de Ouvigo. After archaeological excavations, more than 40 years ago, it was generally accepted that this building preserves, at least, a Late Roman (4th and 5th centuries) constructive phase with later modifications introduced in the Early and Late Middle Ages. However, neither stratigraphical nor chronological evidence confirmed this interpretation. Five samples from three different constructive phases have been taken for OSL dating. Small quartz multi-grain aliquots were used for dating. Results provide ages in agreement with expectations for the mortars of the Late Roman phase but, they show the need of a new interpretation of the chronological model assigned to the building. Such model could be corroborated in a next phase of the project that intends to characterize the mortars and using radiocarbon dating.