MARCHETTI M.
Forme e depositi fluviali, fluvioglaciali, lacustri – Fluvial, fluvioglacial and lacustrine forms and deposits
Pages 73-104
Abstract
One of the most interesting aspects of the system ofalluvial sedimentation in the Po Plain is the difference between surface deposits North of the river) with respect to those South of it; the Veneto sector also has characteristicswhich are completely different from both. The observed differences undoubtedly have many causes) including the considerable importance of the stratigraphic and geodynamic features of the two mountain chains) as well as the structural and tectonic characteristics peculiar to the various sectors. The river Po) subparallel to the tectonic directions of the two chains) divides its true plain into two parts: southern) mainly supplied by the Apennines) and northern) fed by the Alps. In the axial zone) the area dominated by the Po) according to subsoil (Gr. St. Falde Acquifere Profonde, 1979) and surface data) starting from its confluence with the Tdnaro, widens eastwards) interfering with the systems of the Adige and the Romagna rivers towards the coastalplain. The two chains feed the Po basin with various types of detritus. The Alps provide mainly dolomia) limestone) silicoclastic and crystalline rocks) deriving from the erosion of the bedrock and ofglacial deposits. The Apennines provide sediments deriving from calcareous and clayey rocks; East ofBologna (East of the Sillaro) sandstone derivates prevail. These differences are reflected in the distribution ofsurface sediments: those coming from the Alps being coarser and sandier with respect to Apennine sources) with prevailing clay and) among these) the sandier deposits outcropping in the sector East of the Sillaro. The basins of the Apennine rivers may be subdivided into two groups according to extent: one group has a mean…