XVI INQUA Congress
Paper No. 3-6
Presentation Time: 1:30 PM-4:30 PM

RIVER RHINE AND CHANNEL RIVER RESPONSE TO LATE QUATERNARY ALLOGENIC FORCING: THE IMPORTANCE OF TECTONIC SETTING

TEBBENS, L.A.1, HOEK, W.Z. Jr1, and VELDKAMP, A.2, (1) Physical Geography, Utrecht Univ, Heidelberglaan 2, Utrecht, NL-3508 TC, Netherlands, w.hoek@geog.uu.nl, (2) Laboratory of Soil Science and Geology, Wageningen Univ, P.O. Box 37, Wageningen, NL-6700 AA, Netherlands

We modelled the Late Quaternary development of the River Rhine longitudinal profile to gain insight into its response to climate change and sea-level change on a timescale of 103-105 years. The 1250-km River Rhine originates in the northwestern European Alps, crosses different tectonic domains and drains towards the European passive continental margin. Results indicate that areas with long-term uplift or long-term subsidence (separated by the hinge line) show very different fluvial response.

Long-term uplift prevails in the drainage basin upstream from the hingeline. Here, phases of aggradation and degradation in the fluvial system are controlled by glacial-interglacial climate change. The Alps and their foreland are uplifted rapidly. Degradation prevails in the Alpine Rhine, but during glacial/stadial periods accumulation is predicted in the foreland. The Upper Rhine Graben constantly subsides, and therefore sedimentary units are stacked during long-term aggradation. The Rhenish Massif and Lower Rhine Embayment are uplifting. Here, glacial/stadial valley aggradation and interglacial/interstadial valley incision have created a staircase of alluvial terraces. Terrace gradient lines have been reconstructed and deposits have been dated to verify the timing of events.

Downstream from the hingeline, the Rhine enters the long-term subsiding Rhine-Meuse delta and Channel region. The Weald anticline, however, is uplifting. Here, aggradation and incision phases along the longitudinal profile mainly result from glacio-eustatic sea-level changes. During the Eemian and early Weichselian sea-level highstands (OIS 5e, 5c, 5a) the Rhine entered and traversed a glacial trough basin (Saalian). The present Rhine takes a shortcut south of this basin towards the Holocene (OIS 1) estuary. Glacio-eustatic sea-level fall during OIS 6, 4 and 2 to max. -130 m extended the Rhine profile with ~900 km. The mouth of the axial Rhine/Channel-River system at those times was located midway between Cornwall and Normandy in the Channel region. The model reproduces the creation of interglacial coastal prisms as a result of increasing accumulation space during sea-level rise, and erosion during early-glacial sea-level fall. These phenomena coincide with a shift of the terrace intersection over hundreds of kilometres.

XVI INQUA Congress
General Information for this Meeting
Session No. 3--Booth# 29
Fluvial Archives of Environmental Change (Posters)
Reno Hilton Resort and Conference Center: Pavilion
1:30 PM-4:30 PM, Thursday, July 24, 2003

Geological Society of America Abstracts with Programs, , p. 68

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