Evidencing a large body of ice in a rock glacier, Vanoise Massif, Northern French Alps

Auteur(s) et Affiliation(s)



Description :
The Sachette rock glacier is an active rock glacier located between 2 660 and 2 480 m a.s.l. in the Vanoise Massif. In order to characterize its status as permafrost feature, shallow ground temperatures were monitored and the surface velocity measured by photogrammetry. The rock glacier exhibits near-surface thermal regimes suggesting permafrost occurrence and also displays significant surface horizontal displacements. In order to investigate its internal structure, a ground-penetrating radar (GPR) survey was performed. The results point towards the existence of a large buried body of ice in the upper part of the rock glacier. The rock glacier was interpreted to result from the former advance and decay of a glacier onto pre-existing deposits, and from subsequent creep of the whole assemblage. This study of the Sachette rock glacier thus highlights the rock glacier as a transitional landform involving the incorporation and preservation of glacier ice in permafrost environments with subsequent evolution arising from periglacial processes.


Type de document :
Article de périodique

Source :
Geografiska annaler. Series A. Physical geography, issn : 0435-3676, 2013, vol. 95, n°. 2, p. 109-123, nombre de pages : 15, Références bibliographiques : 2 p.

Date :
2013

Editeur :
Pays édition : Suede, Stockholm, Svenska sällskapet för antropologi och geografi