Evidence of Seasonal Uplift in the Argentière Glacier (Mont Blanc Area, France)

Autor: Christian Vincent, Adrien Gilbert, Andrea Walpersdorf, Florent Gimbert, Olivier Gagliardini, Bruno Jourdain, Juan Pedro Roldan Blasco, Olivier Laarman, Luc Piard, Delphine Six, Luc Moreau, Diego Cusicanqui, Emmanuel Thibert
Přispěvatelé: Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Chamonix Glaciol Association, ANR-18-CE01-0015,SAUSSURE,Glissement des glaciers et pression hydrologique sous glaciaire en relat(2018)
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Journal of Geophysical Research: Earth Surface
Journal of Geophysical Research: Earth Surface, 2022, 127 (7), pp.e2021JF006454. ⟨10.1029/2021jf006454⟩
ISSN: 2169-9003
2169-9011
Popis: International audience; The hydromechanical processes by which basal water controls sliding at the glacier bed are poorly known, despite glacier basal motion being responsible for a large part of ice flux in temperate alpine glaciers. Previous studies suggest that sliding strongly relates to the quantity of water being stored at the ice-bedrock interface. However, this water storage is difficult to quantify accurately on the basis of surface-motion observations, given that uplift can also be affected by changes in vertical-strain rates and sliding velocity change. Here, we use a comprehensive data set of in situ measurements performed over 2 years on the Argentière Glacier in the French Alps to investigate the relationships between horizontal and vertical velocities, basal sliding, subglacial runoff and bed separation. We observe strikingly large uplifts varying spatially between 0.20 and 0.90 m over the winter/spring seasons between January and June and with a consistent spatial pattern from 1 year to another. We show, based on observations and three dimensional ice-flow modeling, that these large uplifts cannot be explained solely by changes in strain rates or in sliding up an inclined bed. Our results reveal that more than 80% of the observed uplift is related to enhanced bed separation through cavitation, allowing us to estimate the volume occupied by water-filled subglacial cavities. Our interpretation of uplift being mainly caused by increased cavitation is also consistent with an associated increase in the observed surface horizontal velocity. These findings provide important observational constraints for testing subglacial hydrological models
Databáze: OpenAIRE
Externí odkaz: