Integrated archaeogeophysical approach for the study of a medieval monastic settlement in Basilicata

The paper deals with the results of an archaeo-geophysical approach adopted for the study and the reconstruction of the architectural plan of the medieval monastery of San Pietro a Cellaria in Calvello (Basilicata, Southern Italy). The monastery is a remarkable witness to Benedectine architecture of the 12-13th century in Basilicata, built by monks of the Congregation of S. Maria di Pulsano, who were active mainly in southern Italy. The historical data and the diachronic architectural study, based on the analysis of building techniques, provide evidence for a long and intense history, during which the monastery underwent several architectural changes, including the demolition of buildings and the superposition of other constructional elements. The only preserved medieval remains are a church with a nave; the adjacent structures are more recent. This preliminary data prompted a research project to shed new light on the as yet unknown history of the medieval monastery. Specifically, a remote sensing approach around the monastery including aerial survey by unmanned aerial vehicle (UAV), ground-penetrating radar (GPR) and geomagnetic survey in gradiometric configuration (MAG), was adopted in order to verify the possible existence of buried masonry structures and other possible features of archaeological interest, including channels and aqueducts. The GPR time slices were constructed from closely spaced parallel profiles. The time slices, computed by averaging radar reflections over vertical time windows several nanoseconds thick, are used to map subsoil features associated with the structures, probably of anthropogenic origin. To facilitate the interpretation of the results, a threedimensional image was constructed using closely spaced parallel profiles, which are linearly interpolated. The MAG survey was carried in gradiometer configuration, in order to study magnetic properties of the shallow subsoil. Ground-penetrating radar gives details about archaeological structures in a limited area where survey was possible, while gradiometer survey confirms GPR results and improves archaeological knowledge in the areas where GPR survey was impossible. This multi-sensor remote sensing program revealed a wide variety of archaeological features of interest, which may be targeted accurately with excavations in the future.