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| Titel |
Approaching sediment dynamics on Little Ice Age (LIA) lateral moraines in Upper Kaunertal valley, Austria using long-lived radionuclide 129I |
| VerfasserIn |
Sarah Kamleitner, Verena Czarnowsky, Johannes Lachner, Peter Steier, David Morche, Sabine Kraushaar |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250121975
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| Publikation (Nr.) |
 EGU/EGU2016-890.pdf |
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| Zusammenfassung |
| The Upper Kaunertal, as many other valleys situated in the Eastern Alps, has recently
undergone large deglaciation processes as a result of global warming, leaving behind large
moraines exposed to geomorphic processes. Steep lateral moraines represent large and
easily erodible sources of material within an Alpine sediment cascade. In order to
quantify the amount of sediments provided by the moraines, methods of surface
change detection such as aerial and terrestrial laser scanning or sfm (structure from
motion) generated Digital Elevation Models (DEM) are being applied. However,
morphological changes due to the melt out of persisted ice are overlain by processes of mass
movement, slope wash, and fluvial erosion, and therefore often remain unnoticed.
Yet melting alone could account for a volume reduction in the sediment matrix of
up to 13%, the additional leaching of water to a further unknown amount. Hence,
the hydrological situation on the lateral moraines needs to be clarified. Previous
investigations of springs evolving from the LIA lateral moraine were showing light isotope
signatures comparable to those of glacier ice, and resulted in first assumption about the
presence of ice lenses within the moraines (Kraushaar et al. 2014). Stable isotope
measurements applied by Czarnowsky et al. 2015 confirm former findings. However, fail to
distinguish between recently developed ice and dead ice lenses originating from
former glacial maxima. This study therefore aims to date evolving spring waters on
lateral moraines of the Gepatschferner, sampled between May and October 2015,
using the radioactive isotope iodine-129. The environmental abundance of this
long-lived radionuclide has been, analogue to tritium, significantly altered due to
human activity since Nuclear Age, and is therefore believed to provide feasible
relative age estimations. Hence, measurements will allow the clarification of the
hydrological situation on site and the specification of processes causing volume
reduction. Furthermore, the results will have implications for the interpretation
of local sediment dynamics as well as the validation of applied surface change
measurements.
Czarnowsky V., Kamleitner S., Knöller K., Heinrich J., Morche D., Kraushaar S. (2015):
Characterization of perennial and episodic springs with stable isotope signatures in the
Kaunertal Valley, Austria. – In: Morche, D., Kraushaar S., Beylich A. (2015): Proceedings of
the 9th I.A.G./A.I.G. working group SEDIBUD (Sediment Budgets in Cold Environments)
Workshop “Sediment Dynamics in Cold Climate Environments”, Kaunertal, Tyrol/Austria,
September 7 - 10, 2015.
Kraushaar, S., Blöthe, J., Baewert, H., Dubberke, K., Culha, C., Knöller, K., Morche, D.
(2014): Supportive methods for sediment budgeting: Stable isotope measurements of
perrenial springs in the Kaunertal valley. – In: Morche, D., Krautblatter, M., Beylich, A.,
Heckmann, T. (2014): Proceedings of the 8th I.A.G./A.I.G. working group SEDIBUD
(Sediment Budgets in Cold Environments) Workshop “Sediment Cascades in Cold
Climate Geosystems”, Zugspitze/Reintal, Bavaria/Germany, September 1 - 3/4, 2014. |
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