OF THE CHURCH AND TOWER OF S. MARTINO Malena

Roberta Conversi Archaeologist, Superintendence for Archaeology, Fine Arts and Landscape for Parma and Piacenza Territories Cristina Mezzadri Archaeologist, private company Malena s.n.c. Piacenza

roberta.conversi@beniculturali.it www.malenasnc.com

Piana di San Martino: Restoration, 3D scan and backfilling of the Church and Tower of S. Martino

In 1990, remains of a multi-layered site were found on Mount San Martino, located in a side valley south of the Po river; the site seems to have been inhabited since proto-historical times up until the modern era. The best evidences come from a late antique settlement, which was founded in a strategic position on a syncline in the Emilan Apennines and re mained inhabited throughout the Middle Ages; the site is actually protected as a Geo-site and archaeological heritage site as well. Archaeological excavations carried out between 2000 and 2017, evidenced structures, stratifications and finds that make possible a reconstruction of the settlement’s evolution. The fortified site was founded as a castrum in the Late Antiquity and was inhabited by Goths, Byzantines and Lombards until the late Middle Ages, when it became a place of Christian worship. The castrum was part of a defensive network operating between the Late Antiquity and the Early Middle Ages. Remarkable are two vaulted underground cis terns, with floor and wall coverings made from cocciopesto. Considering its importance, the site was included in an international study project, and since 2018, the Italian Ministry of Cultural Heritage has been funding the conservation, res toration, 3D scanning and backfilling of the foundation walls under the castrum’s tower and the Church of San Martino, which was actually built on the tower by carving the rocky ridge. The aim of this research project was to acquire decisive data about the construction of a rectangular building, probably a large hall with a tower which was later converted into a Christian place of worship during the Middle Ages. This church, dedicated to the Saints George and Martin, had only one hall and an apse on the eastern side, which was partially

made of blocks of stones and partially carved in the rock. On the façade wall, near the entrance, four tombs were found, each with a trench carved in the rock. The structures, excavated years ago, were partially colonised by vegetation, and have been cleaned up manually. During an analysis of the conservation conditions, were identified many critical points with stones detached or flaked, especially due to the mortar almost completely worn Open-air conservation and showing is currently not possible due to the conditions of the structures; however, their presence characterize the environment of a clearing in a chest nut wood, very popular with tourists and hikers. For securing the permanent structures, it has been necessary look out for methods which need no supplying and transportation of heavy materials, since the area is only accessible through hiking trails. For this same reason, heavy machinery use have been excluded dur ing covering activities, also considering the easy reversibility of the procedure. Partial backfill was possible through the creation of “wall sacrifice-surfaces” manufac tured by local expert artisans. The field and its structures have been protected with breathable geotextile, and hollow parts have been filled with blocks of polystyrene, then covered with soil from the excavations and gravel. The archaeological relief has been carried out through 3D modelling with real texture of all stratigraphic units and excavation phases, which allows to keep scientific accuracy in short operating times and is the basis for further elaborations aimed at valorisation. This system is characterised primarily by its preciseness: it requires an operative structure with specific interdisciplinary competences and property technologies.

In short, the process develops through the following operative phases: _ Photographic report of the panorama and some details through drone flights _ Georeferencing through GPS _ In-field topography _ Filming both from a drone and on the ground through a measuring camera _ Creation of the 3D model _ Orthophoto in the desired scale _ AutoCAD drawing file _ Delivery of the 3D model of the site The three-dimensional model serves then as a long-lasting searchable database; logging into it, it is possible to extract archaeological and geometrical information (such as plani metries, sections, prospects, areas and volumes). These three-dimensional models can also be converted into .PDF format, which is acces sible to all and allows to rotate and measure the models and to insert them in text files for publications/publishing or slideshows. The 3D texturized model allows a further “story-telling” of the excavation through a navi gable 3D model.