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Unraveling paraglacial activity on Sierra de Gredos, Central Spain : A study based on geomorphic markers, stratigraphy and OSL

Auteur(s) et Affiliation(s)

Dept. de Geología Regional, Inst. de Geología, UNAM, Mexico, Mexique
CASTILLO, M.
Dept. de Geología Regional, Inst. de Geología, UNAM, Mexico, Mexique
SANDERSON, D.
Scottish Universities Environmental Research Centre (SUERC), East Kilbride, Royaume-Uni
KINNAIRD, T.
Scottish Universities Environmental Research Centre (SUERC), East Kilbride, Royaume-Uni


Description :
The AA. use luminescence signals from debris flow and fluvial deposits as well as OSL dating of 3 deposits to detect the main paraglacial processes in Gredos Gorge, a glaciated valley of Sierra de Gredos (Central Spain). They identify 2 major phases of paraglacial activity during and after the retreat of Last Glacial Maximum (LGM) glaciers. The first phase consisted of high discharge debris flows, sourced up-valley, triggered during the deglaciation. The second phase started ~ 11 ka and is characterized by 2 processes : (1) the triggering of low discharge debris flows sourced on the flanks of moraines, and (2) the reworking of paraglacial deposits by rivers. The results of OSL signals, stratigraphy markers and sediment volume indicate that during and after the deglaciation of Gredos Gorge, paraglacial sediment was depleted as theory predicts. The AA. propose that the poor coverage of vegetation driven by the Mediterranean climate prevents the stabilization of glacigenic sediment that is only mobilized during high discharge events responding to extreme rainfalls.


Type de document :
Article de périodique

Source :
Catena (Giessen), issn : 0341-8162, 2013, vol. 110, p. 207-214, nombre de pages : 8, Références bibliographiques : 40 ref.

Date :
2013

Editeur :
Pays édition : Allemagne, Cremlingen-Destedt, Catena

Langue :
Anglais
Droits :
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