EVIDENCE OF AN EARLY PLEISTOCENE INTERGLA CIAL EVENT WITHIN A FLUVIALFORMATION OF COTENTIN (WESTERN-NORMANDY, FRANCE)

Evidence of an Early Pleistocene interglacial event within a fluvial f ormation of Cotentin (western-Normandy, France). A new formation refer red to as the ''Sables de La Lande de Millieres'' and made of fluvial sands and gravels has been discovered in the western part of the Coten tin region close to Millieres. This formation is overlain by Holocene peat and uncomformable with underlying Plio-Pleistocene marine sandy s trata (so-called ''Sables de Saint-Vigor''). These sands overlay Reuve rian-Praetiglian marine deposits which were defined at Marchesieux. In its upper part, the Sables de La Lande de Millieres Formation contain s peaty and organic levels within clays and silts. In western Normandy , this formation is the first evidence for fluvial sedimentation durin g an Early Pleistocene interglacial event. A multidisciplinary approac h (palynology, tectonic, sedimentology and geochemistry) has been carr ied out on peaty and organic levels. It allows us to understand their sedimentary environment and the different stages of their emplacement. Compared with known English, Dutch and German Plio-Pleistocene deposi ts, the palynological study shows evidences for a late Waalian and ear ly Menapian age.