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| Titel |
A 10Be-based sediment budget of the Upper Rhône basin, Central Swiss Alps |
| VerfasserIn |
Laura Stutenbecker, Romain Delunel, Fritz Schlunegger, Naki Akçar, Marcus Christl |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250141905
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| Publikation (Nr.) |
 EGU/EGU2017-5459.pdf |
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| Zusammenfassung |
| The Upper Rhône catchment located in southwestern Switzerland is one of the largest Alpine
intramontane basins and, due to high topographic gradients and intense glacial conditioning,
an important sediment factory in the Alps. Sediment is being produced in around 50
tributary basins, transported along the 150 km long course of the Rhône River, and
deposited in the river delta and associated subaquatic canyons within Lake Geneva, its
primary sedimentary sink. In order to quantify the modern sediment fluxes in this
Alpine basin we infer catchment-wide denudation rates from concentrations of the
cosmogenic nuclide 10Be in quartz extracted from modern fluvial sediment of the major
tributary basins. Additionally, 10Be-based denudation rates are calculated for 14
locations along the main Rhône River to track downstream changes. Results from the
tributary basins show a large scatter of 10Be concentrations and their respective
inferred denudation rates, ranging from 9.72 x 104 atoms/g and 0.17 mm/a to 0.13
x 104 atoms/g and 2.64 mm/a. The Rhône basin does show a rather large spatial
variability of parameters that are known to possibly influence denudation rates, for
example recent rock uplift rates, lithology, precipitation and temperature, as well
as geomorphological parameters such as relief, mean elevation and slope values.
However, there is no significant correlation between those parameters and the calculated
denudation rates. Instead, the denudation rates are found to be positively correlated with
the recent glacial cover in the catchments. This suggests that in glaciated basins
glaciogenic material with very low 10Be concentrations is the dominating source of
sediment, and inferred denudation rates must be interpreted with great care, as they may
overestimate the actual rates. Downstream the main Rhône River the 10Be-concentrations
are rather stable and do not record significant inputs of the glaciogenic material
supplied by the glaciated basins. Possible explanations we would like to discuss
here include differences in sediment connectivity and temporary sediment storage. |
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