Late Pleistocene evolution of the Rhine in the southern North-Sea Basin: imprints of climate change, sea-level oscillations and glacio-isostacy

High-resolution continuous core material, geophysical measurements, and hundreds of archived core descriptions enabled to
identify 13 Late Pleistocene Rhine-Meuse sedimentary units in the infill of the southern part of the North Sea basin (the Netherlands,
northwestern Europe). This sediment record and a large set of Optical Stimulated Luminescence dates, 14C dates and biostratigraphical
data, allowed to establish detailed relationships between climate change, sea-level oscillation, glaciation history and the sedimentary
development of the Rhine fluvial system during the last glacial cycle (Marine Isotope Stages 5e-2, Eemian-Weichselian). A well-preserved
Eemian sediment record was encountered as the infill of a Late Saalian (MIS6) subglacial basin. Part of this record reflects groundwater
rise controlled (fine-grained) sedimentation as a result of postglacial (early) Eemian sea-level rise. It shows strong analogy to
developments known from the Holocene Rhine-Meuse delta. Outside of the glacial depressions near coastal deposits are only
fragmentarily preserved. The Early Glacial Rhine sediment record is dominated by organic debris and peat layers, marking
landscape stability and low fluvial activity. Part of this record may have been formed under near coastal conditions. Significant amounts
of reworked marine biomarkers in the lag-deposits of Early Pleniglacial (MIS4) fluvial systems indicate that this period is characterized
by extensive reworking of older (MIS5) near-coastal sediments. Despite the marked Early Pleniglacial climatic cooling, input of new
sediment from the drainage basin was relatively low, a feature that is related to the presence of regolith protective relic soil complexes in
the basin. During the early Middle Pleniglacial, a major Rhine avulsion indicates the system was in an aggrading mode and that
sediment supply into the lower reaches of the Rhine had strongly increased. This increase in sediment supply coincided with the timing of
major climate cooling that occurred from 50 to 45 ka onwards. The increase in sediment supply is related to final breakup of
the soil complexes in the drainage basin. After 24 ka, a strong input of coarse-grained gravelly sediments was observed which
indicates a strong increase in physical weathering processes and periglacial-controlled supply of bedload sediment in the catchment.
A time delay between climate change (30 ka) and channel belt aggradation (o24 ka), is explained as a result of transport
path length between source and sink and/or effects of higher continental runoff rates after 22 ka. The Late Middle Pleniglacial,
Late Pleniglacial and Lateglacial Rhine-Meuse record testifies for strong influence of glacio-isostatic-controlled differential upwarping of
the study area. Glacio-isostatic-controlled forebulge upwarping and lateral valley tilting is shown to have deflected Rhine-Meuse
channel belts after 35 ka. Glacio-isostatic upwarping is seen as the main cause for strong incision during the first phase
of the Late Pleniglacial (30–24 ka). At later stage glacio-isostatic-controlled incision was overruled due to high climate-controlled sediment input from the catchment and probably initial glacio-isostatic subsidence. Migration of channel belts towards the
direction of the former centre of glacio-isostatic uplift indicates that glacio-isostacy influenced Rhine-Meuse paleogeography until far
into the Lateglacial.