Absolute dating of construction materials and petrological characterisation of mortars from the Santalla de Bóveda Monument (Lugo, Spain)

Abstract

The construction materials of the Santalla de Bóveda Monument, one of the most studied buildings in Galicia (Spain), are analysed to date the mortars and bricks of walls and vaults by combining three dating techniques: optically stimulated luminescence, radiocarbon and thermoluminescence. Petrological characterisation of the mortars themselves is carried out. Until now, the paintings on the vault have been interpreted as Roman, early Christian or Pre-Romanesque, depending on the interpretative framework used by the researcher who studied them. There is also no consensus on their functionality. A total of 21 samples were collected, and 39 datings were made. The results are conclusive: the original building dates from the second half of the fourth century AD, the paintings date from the beginning of the seventh century or the upper floor from the tenth to twelfth centuries. These results make it necessary to review the history of Galician architecture between Late Antiquity and the Early Medieval Ages.