Late Quaternary oligotypical non-marine mollusc fauna from southern Tuscany: climatic and stratigraphic implications GIOVANNI SARTI 1 ,GIOVANNI ZANCHETTA 1 ,LORENZO CIULLI 1 and ANDRE Â COLONESE 2 1 Dipartimento di Scienze della Terra, Universita Á di Pisa, Via S. Maria, 53, 56126 Pisa, Italy. 2 Dipartimento di Archeologia e Storia delle Arti, Universita Á di Siena, Via delle Cerchia 5, 53100 Siena, Italy. Abstract An oligotypical non-marine mollusc assemblage, indicating arid and likely cold climate conditions, has been found in the sea cliff-section of Baratti Gulf (southern Tuscany). The succession is constituted by an alternation of marine, coastal and continental deposits comprised between marine isotope substage (MIS) 5c and MIS 1. Eleven lithostratigraphic units have been recognised. According to previous dating work, the non-marine mollusc assemblage has been correlated to MIS 4. The global sea-level curves compared to the stratigraphic reconstruction at Baratti, suggest a first phase of subsidence followed by a very recent uplift. These data are in conflict with other neotectonic reconstruction based on MIS 5e markers for this area. Keywords: Non-marine fauna, Late Quaternary, Sea-level changes, Tectonics, Tuscany. Introduction Non-marine mollusc assemblages are a suitable tool for the reconstruction of past environments on land (Loz Æek, 1964; Puisse Âgur, 1976; Rousseau and Puisse Âgur, 1999; Rousseau et al., 1992; Li- mondin-Lozouet and Antoine, 2001). In parti- cular, oligotypical assemblages are considered ty- pical of cold and arid phases that developed dur- ing pleniglacial conditions in Continental Europe (e.g. Loz Æek, 1964; 1990; 2001; Puisse Âgur, 1976). Although a strict comparison cannot be per- formed, in Central Italy non-marine oligotypical assemblages have been found as characteristic of cold and arid phases, which in well strati- graphically constrained conditions have been correlated with pleniglacial (e.g. Esu, 1981; Esu et al., 1989; Di Vito et al., 1998). Some of these as- semblages show the presence of more thermo- philous elements, suggesting that the temperature was not as rigid as indicated by non-marine as- semblages of central Europe (e.g. Di Vito et al., 1998; Marcolini et al., 2003). The interest of non- marine oligotypical fauna is of paramount im- portance from a biogeographic and stratigraphic point a view. However, these findings are still re- latively rare in Italy; consequently, the structure and significance of these past ``biocenosis'' need to be progressively constrained by new findings on a larger geographical extent. This paper describes a non-marine fauna recovered from an upper Pleistocene coastal to continental succession cropping out in the Gulf of Baratti (southern Tuscany, Fig. 1). This finding gives also the op- portunity to revise the local stratigraphy, which still presents several problems of interpretation. Previous studies The succession cropping out along the sea cliff of the Gulf of Baratti (Fig. 1) has been studied in the past by Cortemiglia et al. (1983), Hearty and Dai Pra (1987), Costantini et al. (1993), and Mauz (1999). These authors recognised at least three or four (Mauz, 1999) distinct sandstone levels of marine beach and/or marine-related aeolian de- posits (locally known as ``Panchina''), separated by reddish silty and sandy, weathered colluvial de- posits (''Sabbie rosse''). These alternations have been correlated to marine oscillations occurred during the Late Pleistocene (i.e., Marine Isotope Stage - MIS 5, 4, 3, 2 and 1). Hearty and Dai Pra (1987), on the basis of aminoacid racemization, attributed the lower sandstone level to MIS 5. Recently, Mauz (1999) dated by thermo- 159 GeoActa, vol. 4, 2005, pp. 159-167, Bologna