Middle Pleistocene vegetation and climate in southern Italy (Boiano Basin, Molise)

摘要

The sedimentary basins of the central and southern Apennines are suitable to the conservation of continental palaeoenvi-ronmental archives. The study of those deposits traces the evolution of vegetation and climates in Italy during the Quaternary, at regional and micro-regional scales. Thus, the Boiano Basin (Molise, Italy) recorded an important lacustrine and fluvio-palustrine sedimentation since the Middle Pleistocene. According to the tephrostratigraphy, which forms the chronological framework of the sequence, the basal deposits are assumed to be older than 440 ka. Three major phases of sedimentation were recognized by means of lithology. Palynology enabled to detail the evolution of the environments synchronous to those sedimentary fillings between the oxygen isotopic stages 13 and 2. The environment dynamics confirms the progressive reduction of the deciduous forest diversity during the Middle Pleistocene, and characteristics of the Boiano basin are enlightened. Quercus, omnipresent element during the Middle Pleistocene of southern Italy, is quite scarce along the whole sequence and systematically associated with Fagus during the interglacial phases. The biotope, characterized by a continuous, atmospheric or edaphic, humidity favoured the persistence of hygro-philous taxa. In fact, Carya is present until the oxygen isotopic stage 9, which represents its latest record in Western Europe. Thus, the Boiano basin could have constituted an ecological refuge for the arboreal flora of the Middle Pleistocene. The physiography of the basin certainly softened the effects of climatic deterioration during glacial episodes.