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| Titel |
Ice cap melting and low viscosity crustal root explain narrow geodetic uplift of the Western Alps |
| VerfasserIn |
Jean Chéry, Manon Genti, Philippe Vernant |
| 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 |
250131297
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| Publikation (Nr.) |
 EGU/EGU2016-11691.pdf |
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| Zusammenfassung |
| More than 10 years of geodetic measurements demonstrate an uplift rate of 1-3 mm/yr of the high topography region of the Western Alps. By contrast, no significant horizontal motion has been detected. Three uplift mechanisms have been proposed so far:
(1) the isostatic response to denudation. However this process is responsible for only a fraction of the observed uplift and
(2) the rebound induced by the Wurmian ice cap melting. This process leads to a broader uplifting region than the one evidenced by geodetic observations.
(3) a deep source motion associated with slab motion or some deep isostatic unbalance.
Using a numerical model accounting for crustal and mantle rheology of the Alps and its foreland, we model the response to Wurmian ice cap melting. We show that a crustal viscosity contrast between the foreland and the central part of the Alps, the later being weaker with a viscosity of 1021 Pa.s, is needed to produce a narrow uplift. The vertical rates are enhanced if the strong uppermost mantle beneath the Moho is interrupted across the Alps, therefore allowing a weak vertical rheological anomaly thanks to the continuity between the low viscosity parts of the crust and mantle.
References:
Champagnac, J.-D., F. Schlunegger, K. Norton, F. von Blanckenburg, L. M. Abbühl, and M. Schwab (2009), Erosion-driven uplift of the modern Central Alps, Tectonophysics, 474(1-2), 236–249.
Vernant, P., F. Hivert, J. Chéry, P. Steer, R. Cattin, and A. Rigo (2013), Erosion-induced isostatic rebound triggers extension in low convergent mountain ranges, geology, 41(4), 467–470. |
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