AGET (VS)

Historical glacier forefield

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Elevation: 2810-2920m - Massif: Grand-Combin - Commune: Bagnes (VS)  

 

The historical proglacial margin of the Aget glacier, located east of Mont Rogneux, features a push moraine, i.e. a large mass of frozen sediments, which was pushed, dragged and deformed by the progression of the glacier during the Little Ice Age. Today the Aget glacier has almost completely disappeared and the push moraine, which is still deeply frozen, creeps back towards the talweg left by the former glacier at a velocity of a few tens of centimeters per year. Our first observations began in 1998 (geoelectrical and thermal measurements). This site is integrated as a "Kinematics Site" into the PERMOS monitoring network (PERmafrost MOnitoring in Switzerland).

 

  • Measurements and observations

    Thermal (ground surface temperature : GST)
    Geophysics (electrical resistivity)
    Geodetic (GNSS)

  • Figures

    Occurence/Absence of permafrost based on electrical resistivity measurements (data: 1998).

     

     

    Measured horizontal flow field (mean annual velocity).

     

     

    Annual horizontal surface velocity in several sections of the push moraine. Mean of selected sets of points.

     

     

    Mean annual ground surface temperature. The orange curve represents the mean temperature of the n sensors installed on the site (grey curves). The orange dotted line is the mean temperature observed since the beginning of the time series.

     

     

    Contribution of the annual Ground Freezing (sum of all daily mean values < 0°C) and Ground Thawing (>0°C) Indexes to the mean annual ground surface temperature (MAGST) on a set of selected locations (n) on the site with indication of the respective trend since the beginning of the time series. Or : how cold was the winter and how warm was the summer at the surface of the ground ?

     

     

    Annual dates of the start and end of the snowmelt period (zero curtain phase). Mean of n sensors placed on permafrost terrain. The dotted lines show the mean dates since the beginning of the time series.

     

  • Publications

    PERMOS 2019. Permafrost in Switzerland 2014/2015 to 2017/2018. Noetzli, J., Pellet, C., and Staub, B. (eds.), Glaciological Report (Permafrost) No. 16-19 of the Cryospheric Commission of the Swiss Academy of Sciences, 104 pp, DOI:10.13093/permos-rep-2019-16-19.  

    Wee, J. (2018). Dynamics of the Aget back-creeping push-moraine from 1998 to 2017. Master thesis, Unit of Geography, Department of Geosciences, University of Fribourg. (pdf).

    PERMOS (2016). Permafrost in Switzerland 2010/2011 to 2013/2014. Noetzli, J., Luethi, R., and Staub, B. (eds.), Glaciological Report (Permafrost) No. 12-15 of the Cryospheric Commission of the Swiss Academy of Sciences, 85 pp. (pdf)

    PERMOS (2013). Permafrost in Switzerland 2008/2009 and 2009/2010. Noetzli, J. (ed.), Glaciological Report (Permafrost) No. 10/11 of the Cryospheric Commission of the Swiss Academy of Sciences, 80 pp. (pdf)

    Delaloye, R. (2004) : Contribution à l’étude du pergélisol de montagne en zone marginale. Série Geofocus, volume 10, p. 152-169 Department of Geosciences, University of Fribourg, 240 p. (pdf)

    Lambiel, C., Delaloye, R. (2004). Contribution of real-time kinematic GPS in the study of creeping mountain permafrost: examples from the Western Swiss Alps. Perm. Perigl. Proc. Vol. 15/3, 229-241. (pdf)

    Delaloye, R., Lambiel, C., Reynard E. & Lugon R. (2003). Réponse du pergélisol à l’avancée glaciaire du petit âge glaciaire : quelques exemples alpins et pyrénéens. Environnements Périglaciaires 10, xxx-xxx (pdf).

    Reynard, E., Delaloye, R., Baron, L., Chapellier, D., Devaud, G., Lambiel, C., Marescot, L. & Monnet, R. (2003). Glacier/permafrost relationships in recently deglaciated forefields of small alpine glaciers, Penninic Alps, Valais, Western Switzerland. Proceedings of the 8th International Conference on Permafrost, Zurich 2003, Vol. 1, 947-952. (pdf).

    Delaloye, R., Devaud, G. (2000). La distribution du pergélisol dans les marges proglaciaires des glaciers de Challand, d’Aget et du Sanetschhorn (Valais, Alpes suisses). Hegg, Ch., Vonder Mühll, D. (Hrsg.) : Beiträge zur Geomorphologie. Proceedings der Fachtagung der Schweizerischen Geomorphologischen Gesellschaft vom 8.-10. Juli 1999 in Bramois (Kt. Wallis). Birmensdorf, Eidgenössischen Forschungsanstalt WSL, 89-96. (pdf).

    Devaud, G. (1999). Etude de la distribution du pergélisol dans les marges proglacaires. L’exemple des marges proglaciaires des Glaciers d’Aget et du Sanetschhorn / VS. Travail de diplôme, Inst. Géogr., Univ. Fribourg. (pdf)