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TOPOALPS - Neogene history of Alpine denudation and source regions (IP3)

English title TOPOALPS - Neogene history of Alpine denudation and source regions (IP3)
Applicant Schlunegger Fritz
Number 120525
Funding scheme Project funding (special)
Research institution Institut für Geologie Universität Bern
Institution of higher education University of Berne - BE
Main discipline Geology
Start/End 01.05.2009 - 30.04.2012
Approved amount 186'544.05
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Keywords (6)

Alps; source to sinks; erosion; geodynamics; sediment source; surface erosion

Lay Summary (English)

Lead
Lay summary
The difficulty in the characterization of glacial and post-glacial landscape impacts stems from the fact that little is known about the chronology of Alpine glaciation, and of how glacial-interglacial cyles have affected the Alpine topography. There are three potential impacts of glaciations on the topographic evolution of the Alps: (i) modification in the surface mass flux, (ii) modification in the overall shape of the Alpine valleys, and (iii) impacts on the present-day routing of sediment. The stratigraphic resolution of the circum-Alpine basins will not allow to estimate the change in surface mass flux in response to Alpine glaciations. Former sediment budget calculations clearly showed that. We will extract this information from the Alpine topography thereby assuming that glacial processes have resulted in a non-steady-state situation of erosion and of topography. We will estimate the magnitude of this non-steady contribution by subtracting the geophysical relief from the present-day topography. This approach was successfully applied to calculate the pattern and magnitudes at which erosion rates increased during the Quaternary for the Western Alps. This tool also allows the modelling of the change of the Alpine valleys in response to glacial processes. We will apply this technique to DEMs from the Central and the Eastern Alps and compare the results with published maps of Alpine glaciations.Changes in the erosional mass flux in the Alps not only left a measurable fingerprint in the topography, but potentially modified the elevation of the baselevel in the foreland via flexural adjustment of the crust to the redistribution of loads. This potential change in the Alpine loads could thus be inferred from maps illustrating top-contour lines of the bedrock underlying Quaternary deposits. Although we will not produce these maps for this project, we will benefit from an ongoing project at the University of Bern in close collaboration with Böhringer AG and the Wasserwirtschaftsamt (Kanton Bern) that aims at restoring the bedrock surface at the Pliocene/Pleistocene boundary for the Swiss Plateau.Most important, however, are the modifications in the source-to-sink relationships caused by glaciations. This is the case because the morphometric properties of a glacial landscape (i.e., steepness, concavity of hillopes and channels, and hillslope-valley relationships) are not in equilibrium to the modern processes. We see a benefit in mapping in detail the source-to-sink relationships on DEMs for selected segments in the Alps (e.g., Central Alps, Easternmost portions of the Alps that were not affected by glaciations). This map will be used as a basis to estimate how glacial processes have modified the pattern of sediment routing.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

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Associated projects

Number Title Start Funding scheme
140219 TopoAlps: Neogene history of Alpine topography - the contribution of glacial erosion 01.05.2012 Project funding (Div. I-III)

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