Middle to Late Pleistocene palaeoenvironmental evolution of the southeastern Alpine Valeriano Creek succession (northeastern Italy) GIOVANNI MONEGATO, 1 * SALLY E. LOWICK, 2 CESARE RAVAZZI, 3 ROBERTA BANINO, 3 MARTA DONEGANA 3 and FRANK PREUSSER 2 1 Dipartimento di Geoscienze, Universita ` degli Studi di Padova, Padova, Italy 2 Institut fu ¨ r Geologie, Universita ¨t Bern, Bern, Switzerland 3 CNR – Istituto per la Dinamica dei Processi Ambientali, Laboratorio di Palinologia e Paleoecologia, Milan, Italy Monegato, G., Lowick, S. E., Ravazzi, C., Banino, R., Donegana, M. and Preusser, F. 2010. Middle to Late Pleistocene palaeoenvironmental evolution of the southeastern Alpine Valeriano Creek succession (northeastern Italy). J. Quaternary Sci., Vol. 25 pp. 617–632. ISSN 0267-8179. Received 10 October 2008; Revised 18 May 2009; Accepted 1 June 2009 ABSTRACT: The Middle–Late Pleistocene alluvial and lacustrine succession of Valeriano Creek (southeastern Alpine foothills, 190 m a.s.l.) documents the environmental evolution of the piedmont plain before the onset of the Last Glacial Maximum (LGM). The sedimentary record was investigated by multidisciplinary stratigraphical and sedimentological studies coupled with petrographic and palaeo- botanical analysis. A chronology has been provided by luminescence, radiocarbon dating and pollen biochronology. The succession developed at the valley mouth of a small catchment and is confined in the piedmont plain by the alluvial fans of major rivers. The oldest deposits were formed during a cold phase during the late Middle Pleistocene. This part of the piedmont plain was generally stable until Termination II, when it was trenched more than 15 m deep by watercourses. The infilling succession of the trench, mostly by low-energy alluvial sediments interbedded with mire and peat deposits, documents, for the first time on the southern side of the Alps, the relationships between fluvial activity, vegetation and climate change at the foothills piedmont plain during late Marine Isotope Stage (MIS) 5. The stadial–interstadial climate forcing implies a local reorganisation of fluvial dynamics and of forest composition, although substantial plant cover persisted even during cooler stadials. In accordance with coeval alluvial and speleothem records from the northern side of the Alps, this environmental evolution supports a very restricted Alpine glaciation of the main fluvial catchments of the southeastern Alps during MIS 5a–d. Copyright # 2009 John Wiley & Sons, Ltd. KEYWORDS: Quaternary; Alps; fluvial dynamics; vegetation history; luminescence; geochronology. Introduction Located downwind of the North Atlantic ocean–atmosphere system, considered the pacemaker of Quaternary climate change, the Alps are a key region for understanding changes in past circulation patterns over Europe. An important issue in this context is the southward shift of the polar front over the North Atlantic, which has apparently caused a reorganisation of atmospheric circulation over Europe and the Mediterranean during glacial times (Florineth and Schlu ¨ chter, 2000; Kuhle- mann et al., 2008). The comparison of archives of past environments to the north and south of the Alps is of crucial importance in understanding these changes in more detail. While a substantial amount of palaeoclimate data is available following the last glaciation of the Alps (i.e. ca. 20 ka), much less is known of the time prior to this and, in particular, the beginning of the last glacial cycle and earlier. The amount of data supported by independent age control on the Pleistocene history of the northern foreland of the Alps has recently increased (cf. Preusser, 2004; Ivy-Ochs et al., 2008), while a great deficit still exists south of the Alps. Besides reconstructing past patterns of climatic development, an important issue in Quaternary science is also to understand how the geosphere responded to climate change. It is therefore desirable to combine information on past environmental conditions with evidence from the geological record concerning, for example, the dynamics of rivers and glaciers. Only then can a comprehensive picture of Quaternary history for a certain area be achieved. The present study contributes to the reconstruction of Middle to Late Pleistocene evolution in the Venetian–Friulian pied- mont plain of the southern Alpine foreland (Fig. 1(a)), which is of special interest due to its proximity to the foothills (Fig. 1(b)) and, in particular, due to its intense tectonic activity during the Quaternary (e.g. Galadini et al., 2005). The location between the Alps and the Adriatic Sea makes it a key area for JOURNAL OF QUATERNARY SCIENCE (2010) 25(5) 617–632 Copyright ß 2009 John Wiley & Sons, Ltd. Published online 6 October 2009 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/jqs.1321 * Correspondence to: G. Monegato, Dipartimento di Geoscienze, Universita ` degli Studi di Padova, Via Giotto 1, 35137 Padova, Italy. E-mail: giovanni.monegate@unipd.it