Modeling longitudinal-profile development in response to Late Quaternary tectonics, climate and sea-level changes: the River Meuse

We present a forward-modelling case study for the development of the longitudinal profile of a basin–marginal fluvial system (River Meuse, NW Europe) responding to Late Quaternary tectonics, climate and sea-level changes. Modelling results show that river reaches in different tectonic domains will respond differently to isochronous events of climate and sea-level change. Climatic change dominates river–valley development in the long-term uplifting upper and middle Meuse reaches (NE Paris Basin, Ardennes, terrace flight area). An alternation of stadial depositional and interstadial erosional phases causes net aggradation of the river valley during glacials, but the river valley considerably degrades during interglacials. The long-term trend in these upper and middle reaches is river–valley degradation. Continuous aggradation leads to long-term deposition during glacials in the subsiding lower Meuse reaches, including the greater part of the Venlo-Block area, the western Roer Valley Graben and the southern part of the West Netherlands Basin. However, decreasing sediment supply combined with increasing discharges at the start of interglacials favours discharge-controlled (kinetic) incision in these net-depositional areas. Post-glacial sea-level rise and the subsequent interglacial highstand strongly influence the subsiding graben areas and the southern West Netherlands Basin. Rising sea level generates a zone of gradient-backfilling that migrates upstream with time. Consequently, the terrace intersection migrates upstream too and a coastal prism is built up during the interglacial highstand. The present case study indicates that the Meuse terrace intersection may migrate to at least 113 km upstream from the modelled coastline. The model also suggests post-interglacial incision of the Eemian highstand coastal prism during the subsequent relative sea-level fall in the Early Weichselian