Climatic oscillations in central Italy during the Last Glacial-Holocene transition:: the record from Lake Accesa

This paper presents an event stratigraphy based on data documenting the history of vegetation cover, lake-level changes and fire frequency, as well as volcanic eruptions, over the Last Glacial-early Holocene transition from a terrestrial sediment sequence recovered at Lake Accesa in Tuscany (north-central Italy). On the basis of an age-depth model inferred from 13 radiocarbon dates and six tephra horizons, the Oldest Dryas-Bolling warming event was dated to ca. 14 560 cal. yr BP and the Younger Dryas event to ca. 12700-11650 cal.yrBP. Four sub-millennial scale cooling phases were recognised from pollen data at ca. 14300-14200, 13900-13700, 13400-13100 and 11350-11150 cal.yrBP. The last three may be Mediterranean equivalents to the Older Dryas (GI-1d), Intra-Allerod (GI-1b) and Preboreal Oscillation (PBO) cooling events defined from the GRIP ice-core and indicate strong climatic linkages between the North Atlantic and Mediterranean areas during the last Termination. The first may correspond to Intra-Bolling cold oscillations registered by various palaeoclimatic records in the North Atlantic region. The lake-level record shows that the sub-millennial scale climatic oscillations which punctuated the last deglaciation were associated in central Italy with different successive patterns of hydrological changes from the Bolling warming to the 8.2 ka cold reversal. Copyright (C) 2006 John Wiley & Sons, Ltd.