Geologia, geomorfologia e stratigrafia

The Ca’ Nova site is part of the upper Parma Apennines and is located in the basin of the Gotra stream, a few hundred metres SE of Monte Chiaro (724 m above sea level), at an average altitude of 675-680 m above sea level. The landscape displays a wide variety of morphological features resulting from the action of morphogenetic processes on a lithologically heterogeneous substrate. The site falls within the geological unit known as the Casanova Complex (Cretaceous) of the Ottone Tectonic Unit, consisting of coarse clastic deposits with turbiditic intercalations and heterometric strips of oceanic and continental lithosphere; a total of four lithozones can be distinguished without a precise stratigraphic order. Towards the south, there are tectonically extensive patches referable to serpentinites. The slopes of Mount Chiaro, often disrupted by landslides and glides and cut by small watersheds, delimit the site to the west. In the immediate vicinity of the site, forms and deposits related to runoff and channelled water flow are identified. The mechanical action of direct rainfall and the runoff of surface water generate erosion phenomena on the slopes, favouring the formation of thick colluvial deposits at the foot of the slopes. It is probable that at the time of the settlement a minor hydrographic network was present, which ensured the outflow of surface waterand allowed the formation of small lake basins or ponds, then progressively filled by debris-colluvial deposits from the surrounding slopes. The stratigraphic sequence uncovered in the trench of the methane pipeline, which crossed the northern sector of the excavation area, is located within a large natural depression. This has been the subject of stratigraphic characterization (facies analysis) and micromorphological analysis. The stratigraphy lies on a powerful debris-colluvial deposit (SU 15), which was covered by partially laminated fine sediments of a ‘lacustrine’ nature (SU 14 and 13), as indicated by the presence of peat and diatoms, and then by additional colluvial sediments with characteristics indicating the establishment of transient hydromorphic conditions (SU 12). Chiefly, SU 13 appears to be rich in carbon fragments pertaining to silver fir, which due to their characteristics, including size, appear to be connected with repeated and extensive forest fires. Finally, the sequence is covered by colluvial deposits (SU 11) from the surrounding areas, in which the Bronze Age artefacts are concentrated, accompanied by angiosperm charcoals, possibly from combustion structures. In the southern sector of the excavation area, descriptive data and micromorphological analysis made it possible to reconstruct the geological-stratigraphic model of the area, highlighting five main types of debris-colluvial deposit that characterize the natural depositional succession. Particular attention was paid to the analysis of the filling facies of two artificial structures (Structure 1 and Structure 2), probably constructed for the drainage or collection of surface water. They were later filled in by natural colluvium, but also by anthropic activities. The analytical description of the charcoal remains at the top of one of the fills of Structure 2 leads to the identification of a burnt stump, which immediately preceded the preparation of an artificial surface, where valuable finds were unearthed.