The Christian Origins of the Ribeira Sacra (Galicia, Spain): Geophysical Prospecting and Photogrammetric Survey

Abstract

In four selected representative religious buildings in the Ribeira Sacra in Spain, we have applied various methodologies and techniques to the study and management of cultural heritage (CH). Geophysical surveys were carried out in the interior and the surrounding territory of three churches – Santa María of Temes, St María of ‘A Ermida’ and the Monastery of St Xoán of Camba – for the first time. The geophysical study consisted of taking data in situ, using linear radiograms, electromagnetic profiles and aerial frames, then processing the data collected through the field work to a depth of approximately -3.0m. with GPR and -7.0m with profilometer. The results have been conclusive and very revealing in all three religious buildings, confirming the existence of two possible late Antique (4th-5th centuries) mausoleums of considerable size and constructive entity in Santa María of Temes and St María of ‘A Ermida’ churches. Moreover, constructive structures of great dimensions and extension were found in the Monastery of San Xoán of Camba, evidencing the presence of a possible early Medieval monastery (9th-10th centuries). In the case of the Monastery of St Pedro of Rocas, the photogrammetry combined with the laser scanner has made it possible to reveal the previous constructive phases and its morphology, related to the hermitic origins and the installation of a group of anchorites in this place. The application of geophysical prospecting techniques, photogrammetry, micro-drone, and laser scanner in these four places, has radically changed our vision of them. These techniques are therefore a fundamental instrument for archaeological research and for the management of heritage by public administrations.