Late Pleistocene climatic changes in central Italy: the pollen record from Stracciacappa (Monti Sabatini volcanic district).
by
Marco Giardini
Dipartimento di Biologia Vegetale, Università "La Sapienza", P.le Aldo Moro 5, 00185 Roma, Italy.

Within the frame of the palaeoenvironmental studies in progress on the crater lakes of central Italy, the lacustrine sediments of Stracciacappa have been drilled and pollen analysed. The Stracciacappa crater is located in the Sabatini volcanic district, about 35 km north of Rome. The lake bed, artificially dried out, lies at 220 m a. s. l., 30-40 m below the surrounding landscape. Its shape is circular, its diameter is approx. 1 km. The stands of natural vegetation living at present in the vicinity of Stracciacappa are formed by deciduous oak woodland with Mediterranean elements. However, most of the landscape has been almost completely modified by human activity for pasture and crops.

A continuous borehole drilled in the center of the lake bed reached the volcanic basement at around 29 m. The lacustrine sediments, containing pollen only in the upper 14 m, are not old enough to record the vegetation history of the St Germain interstadials. A number of radiocarbon dates, between 36,330±1,630 and 12,060±130 years BP, and a comparison with other long palynological sequences of central Italy suggest for the Stracciacappa pollen record an age of approx. 60,000 years.

Stracciacappa is one of the most sensitive sites of the Lazio region to the pleniglacial climatic changes. In fact the pollen sequence shows a number of oscillations of arboreal vegetation, interrupting the succession of steppe and grassland formations dominated by Artemisia, Gramineae and Chenopodiaceae. There is little doubt that these weak expansions of arboreal vegetation correspond to the middle pleniglacial interstadials recognized in the long pollen records throughout Europe. Compared to central and northern Europe, the record of Stracciacappa shows a significant vegetational complexity and a wealth of minor oscillations, as at other Italian sites.

The presence of these weak expansions of arboreal vegetation suggest that the Lazio region, because of its particular geographic position in the centre of Italian peninsula, the diversity of its lithology and the complexity of its geomorphology, is a privileged area of tree refugia.

The tree fluctuations can be correlated among different pollen records in long continuous sequences of the Italian peninsula (Valle di Castiglione, Lago di Vico, Lagaccione, Lago Grande di Monticchio). Attempts to compare these episodes of tree vegetation with the Dansgaard/Oeschger events or to trace the Heinrich events appears very difficult.

Date received: May 15, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cahr-04.