Stratigraphic and palaeontologic aspects of Middle Pleistocene continental deposits from Lower Valdarno (Tuscany).

A multidisciplinary study on Middle Pleistocene continental deposits outcropping between S. Romano and La Rotta (Pisa) recognised two distinct units from lithostratigraphic point of view: Cava Erta Unit and S. Romano Unit. Cava Erta Unit, the oldest one, has been attributed to the beginning of Middle Pleistocene. The presence of mammal remains, among which Dama clactoniana, and a volcanic ash level at the top of the sequence dated to 0.5 Ma, suggest S. Romano Unit belongs to the final part of Middle Pleistocene. Continental mollusc assemblages from S. Romano Unit point out a climate trend from the cool and arid condition of the basal portion to a temperate-humid condition at the top of the succession. Pollen assemblages are strongly altered by pedogenic processes. Stable isotope analyses of land snails and carbonate concretions suggest a today like climate condition for the middle-upper part of the series