Geologia, geomorfologia e vini nel Parco Nazionale delle Cinque Terre

Geology, geomorphology and wines in the Cinque TerreNational Park (Liguria, Italy) - The study area occupies a good deal of the National Park (Parco Nazionale delle Cinque Terre) in eastern Liguria and is covered almost completely by vineyards of the famous denomination DOC Cinque Terre (150 ha). The name «Cinque Terre» is from the five villages of Riomaggiore, Manarola, Corniglia, Vernazza, Monterosso al Mare, in the La Spezia province. The landscape is characterized by a narrow strip of coastline that continues for about 15 km, bounded to the Northeast by the drainage divide which, running parallel to the coast and reaching altitudes of 600 to 800 m, separates the park from the Vara Valley (Val di Vara). Seventy percent of the area faces between west and southeast, with strong preference to the southwest. Five tectonic units are present in the area, the most represented being the sandstones of the Macigno. This youngest Tuscan Unit, represented to the southeast by a stratigraphic succession of Oligocene age, crops out along the promontory between La Spezia and Portovenere as part of an overturned limb of a large SW-verging anticline. Three geologic sections (see the geologic map in fig. 1) illustrate the bedding attitudes of the sandstones between Scoglio Ferale to the south-east and Vernazza to the north-west. The Macigno turbiditic sandstones, nearly vertical from Capo Persico to Manarola, are overthrusted by the Canetolo Unit between Manarola and Corniglia, which is mostly made up of claystone intercalated with carbonates, with ages ranging from Late Cretaceous to Eocene. Near Monterosso, the Monte Veri, Bracco, and Monte Gottero Units overlie the Macigno Unit. Extensive blankets of debris are found across the entire area considered, mostly organized as terraces constructed by man over the centuries and are now partly abandoned and demolished by natural agents or overgrown by shrubby vegetation, pines and other Mediterranean woods. Since about 1100 A.D., cultivation of grapes and also olives was developed upon these man-made terraces; narrow terraces were sustained by drystone walls that run for a total linear distance of nearly 6000 km calculated on an area of ca. 2000 ha. The vineyards are only found on the terraces built on the Macigno, Canetolo, and Monte Veri Units, but are absent on the serpentines and gabbros of the Bracco Unit. However, they are found on the associated Argille a palombini. Furthermore, vineyards are also found on the Scisti Zonati but not on the overlying Monte Gottero sandstones. The total natural nitrogen resulted sufficient in the whole area; the natural phosphorous is well represented in the area of Corniglia, and insufficient in the areas of Vernazza, Manarola, Riomaggiore and Campiglia; it is scarce at Monterosso; the potassium oxide resulted barely sufficient in the area of Corniglia and Manarola, while magnesium oxide is uniform across the entire district. All these informations are of great importance for the sake of vineyard planting, but still they give us very general indications on the correlation between terroir and wine; in fact, the tastings performed on the wines currently available on the market, although highlight some vague indications on the connection between soil type and wine flavours, cannot be considered as an ultimate answer to this problem. Thus, a proposal for an experiment is outlined here. The aim is to understand the correlation between type of soil and wine taste in the area of Cinque Terre. We point out the input and output variables to be considered and analyzed. We suggest the method to be used to design the experiments and to analyze the data, and we outline the steps to be accomplished for the definition of the project.