Indagini geoarcheologiche integrate nel Molise centrale (Italia meridionale): il ponte romano di Tufara

Although the Molise region is being discovered to be of exceptional value as to his archaeological and historical heritage, the frame about the spatial-temporal distribution of settlements and related economical-cultural expressions is full of gaps. This circumstance clearly evidences the difficulties to relate archaeological data to the environmental contexts and changes and to investigate the influence of the latter ones on human events. The present paper illustrates one of the first experiences of geoarchaeological investigation in the central Molise area region which is based on an integrated approach of archaeological, geophysical and geomorphologic analyses. The structure which has been investigated is localized in the medium-lower valley of the Fortore river in locality Pesco del Ponte, municipality of Tufara (Southern Italy). At this site, remains of a Roman bridge were exposed along the left bank of the Fortore river after a flood event in January 2003. Said remains consist in a pillar of a bridge which can be dated, on the basis of the technique used for the working of the rock blocks, to the Republican age (II-I centuries BC). Superimposed on the Roman remains are remnants of a brick work with mortar which indicate a remaking of the bridge in Medieval times. The discovery of the Roman bridge is very interesting as it documents the presence of a road crossing the Fortore river just there. As suggested by the analysis of literature and cartographic-historical documents, that road could be one of the two main ones that met within the centre of the ancient Saepinum. It gives further evidence of the strategic role the Fortore valley played in historical times as the natural connection between the Sannium to the west and the Daunia to the east. To evaluate the prosecution of the bridge structure in the sub-soil, electric vertical soundings based on the dipolar method have been carried out. These soundings have allowed the restitution of tomographic sections showing the anomalies in resistivity at different depths. The reconstructed anomalies clearly evidence the presence, at a few meters depth, of a structure which can be most probably identified with the prosecution of the bridge. Geomorphologic analyses have allowed us to evidence that fluvial dynamics has greatly influenced the stability of the valley bottom in historical times. A number of important variations in height of the valley floor related to alternating phenomena of valley incision and filling could be reconstructed. Particularly, beginning from a valley floor level at about – 3 m from the present one, on which the Roman bridge was constructed, at least three events of flooding could be reconstructed which first caused the damaging of the bridge and then the destruction and burial of the Roman and the superimposed Medieval structure cumulating a valley aggradation of about six meters. In synthesis, the geophysical and geomorphologic analyses have contributed in a significant way to the interpretation of the archaeological site, the first approach by giving valid indications about the probable prosecution of the bridge, useful for future excavation, the second one by allowing to detail the morphologic and dynamic contexts which have characterised the Fortore valley floor from Roman to late Medieval times. On the other hand, the archaeological data have given an essential contribution to define the chronological frame of the reconstructed sequence of events, and therefore also to the investigation into the role of human or climatic factors.