Onset of major Pleistocene glaciations in the Alps.

During maximum Pleistocene glacial expansions, the Alpine icecap invaded the Central Europe uplands and Italian Southalpine foothills. Peri-glacial sedimentary basins, such as the Po Basin, are natural collectors of the past biological and climatic changes that involve the waxing and waning of major icecaps. In a 200 m-long core from the central Po plain, stratigraphic evidence for one such major glacial pulse of the nearby Alpine icecap is registered by a sequence boundary, termed RS, associated with a drastic reorganization of vegetational, fluvial and Alpine drainage patterns. The RS, seismically traceable across much of the Po plain subsurface, was constrained magnetostratigraphically to the first prominent Pleistocene glacio-eustatic low-stand of Marine Isotope Stage (MIS) 22 at 0.87 Ma. MIS 22 corresponds to the end of the 'Mid Pleistocene Revolution' (MPR), characterized by a marked reorganization of Northern Hemisphere glaciation pattern that took place in the late Early Pleistocene. We suggest that the RS formed at MPR/MIS 22 time, during the onset of the first major Pleistocene glaciation in the Alps.