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| Titel |
Quaternary downcutting rates from cave-deposited river sediment and Holocene erosion rates from river sand in the Central Pyrenees |
| VerfasserIn |
Philippe Vernant, Manon Genti, Jean Chéry, Gaël Cazes, Régis Braucher |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250133518
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| Publikation (Nr.) |
 EGU/EGU2016-14138.pdf |
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| Zusammenfassung |
| We use 26Al and 10Be to infer the time of cave-deposited river sediment emplacement in the
Central Pyrenees and the Cevennes. Using these ages, we derive mid-term downcutting rates
(1-4.106 a). We also use the cosmogenic radionuclides 10Be concentration in quartz extracted
from river sand to estimate short-term (102–105 a) erosion rates. Along the N-S profile across
the central Pyrenees, we do not see any significant change in erosion rates during the
Quaternary. On the other hand, the erosion rates are highly correlated with the local elevation.
They vary roughly from 50 m/Myr in the foreland up to 800 m/Myr in the axial part of
the mountain range. The mechanisms responsible for the Pyrenees moderate, but
frequent, seismicity have yet to be determined. Based on numerical modeling and our
erosion rates, we propose that this seismicity could be explained by the isostatic
rebound associated to the erosion of the range. To evaluate the likeliness of this
hypothesis, we aim at comparing the Pyrenees and the Cevennes to check if the rates are
significantly different between these mountain ranges with very different seismic
behavior. |
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