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| Titel |
Constraining local subglacial bedrock erosion rates with cosmogenic nuclides |
| VerfasserIn |
Christian Wirsig, Susan Ivy-Ochs, Marcus Christl, Jürgen Reitner, Martin Reindl, Mathias Bichler, Christof Vockenhuber, Naki Akçar, Christian Schlüchter |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250092634
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| Publikation (Nr.) |
 EGU/EGU2014-6992.pdf |
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| Schlagwörter |
Kosmogene Nuklide, Monte-Carlo-Simulation, Erosion, Erosionsrate, Eisbedeckung, Quartär |
| Geograf. Schlagwort |
Österreich, Salzburg, Zell am See (Bezirk), Goldbergkees, Goldberggruppe, Hohe Tauern, Schweiz |
| Blattnummer |
154 [Rauris] |
| Blattnummer (UTM) |
3227 [Großglockner] |
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| Zusammenfassung |
| The constant buildup of cosmogenic nuclides, most prominently 10Be, in exposed rock
surfaces is routinely employed for dating various landforms such as landslides or
glacial moraines. One fundamental assumption is that no cosmogenic nuclides were
initially present in the rock, before the event to be dated. In the context of glacially
formed landscapes it is commonly assumed that subglacial erosion of at least a few
meters of bedrock during the period of ice coverage is sufficient to remove any
previously accumulated nuclides, since the production of 10Be ceases at a depth of
2-3 m. Insufficient subglacial erosion leads to overestimation of surface exposure
ages. If the time since the retreat of the glacier is known, however, a discordant
concentration of cosmogenic nuclides delivers information about the depth of subglacial
erosion.
Here we present data from proglacial bedrock at two sites in the Alps. Goldbergkees in
the Hohe Tauern National Park in Austria and Gruebengletscher in the Grimsel Pass area in
Switzerland. Samples were taken inside as well as outside of the glaciers’ Little Ice Age
extent. Measured nuclide concentrations are analyzed with the help of a MATLAB model
simulating periods of exposure or glacial cover of user-definable length and erosion rates. |
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