The entrance of Earth's climate into the present icehouse state during a time of rapid temperature decline in the late Pliocene was intensively investigated during the past decade. Even though it is well documented in marine archives, detailed reconstruction of the Pliocene-Pleistocene climatic evolution of central Europe is hampered by a general lack of data. The work presented here is based on sedimentary material from drill cores obtained at three sites within the Heidelberg Basin (Germany). The scientific relevance of this unique archive was discovered only in the last decade. The hundreds of metres thick sequences of mainly fluvial sediments record the evolution of the environment and climatic conditions during the late Pliocene and the entire Pleistocene of western central Europe. In our present study, we implement unpublished mineral magnetic S-ratio data and new evidence from X-ray analysis into two previously completed studies on the magnetic polarity stratigraphy and the magnetic mineralogy of the Pliocene to Pleistocene sediments of the Heidelberg Basin. The total set of data enable distinction of environmental and climatic processes, and unveil details on the climatic conditions of continental Europe during this period. We demonstrate the dominance of an Mediterranean type to subtropical type climate during the Pliocene. Cyclic variations in the groundwater table in the Rhine flood plain resulted in redox fluctuations, which led to the decomposition of the primary detrital mineral assemblage. Authigenic Fe oxides, particularly haematite, formed during dry periods. A rapid transition into cooler and moister conditions occurred at the end of the Pliocene, as indicated by the persistence of Fe sulphides, especially greigite. A high groundwater table and the associated reducing conditions have largely persisted to the present day. We show that the rapid transition from warm to cooler and moister climatic conditions in central Europe during the final Pliocene is a regional response to the intensification of Northern Hemisphere glaciation (iNHG). This work supplements existing knowledge of the climatic evolution of central Europe during the Pliocene-Pleistocene transition by data from a region from which little data has been available. A sideglance to climatic archives elsewhere in the Northern Hemisphere (e.g., North Atlantic Ocean, Chinese Loess Plateau, Russian arctic) is used to show the coincidence of the iNHG events in quite different environmental regimes.
