Palynological evidence of upper Neogene environments in Italy

Palynological studies carried out in several Italian sites contributed to outline the palaeofloristic and palaeovegetational history of the Mediterranean area and to a better understanding of the complex relationships between climate, tectonics and eustatism, during the Messinian and the Pliocene. In the Mediterranean area, the Messinian has long been associated with an overall warm and dry climate whereas recent researches indicate either a warm and humid or a cool and dry climate. The integrated stratigraphic record of vegetational and climatic changes from different Italian sites provides the solution to this apparent contradiction. On the whole a subtropical to warm temperate climate was dominant, although there are major differences in both temperature and moisture values between the coeval upper Neogene sections from northern and southern Italian domains, revealing climatic gradients within the Mediterranean area, at least from the Messinian. During the deposition of evaporitic sediments, dry conditions prevailed in the southern domains whereas relatively humid conditions established in the northern ones. In the upper part of the Late Messinian and during the early Pliocene, progressive increase of both the Tsuga-Cedrus complex and mountain taxa, as well as the strong decrease in herbaceous plants, highlight the differences between northern and southern domains. The Zanclean was characterized by quite uniform warm conditions (from moderately dry, in the south, to humid, in the north) compared to the Piacenzian, when major floristic impoverishment occurred, marked by a strong decrease or even a disappearance of some subtropical and warm temperate taxa.