Sediment transfer at the front of rapidly moving rock glaciers

Rock glaciers acts as sediment conveyors in periglacial alpine hillslopes. Large volumes of rock debris originating from headwalls and moraines are slowly transported downward by permafrost creep. In the Alps, most rock glaciers can be considered as sediment traps, because the sediment output at their margin is usually small. However, a significant erosion rate can be observed at the front of some rock glaciers.

 

A first aim of this research project was to investigate the erosion mechanisms at play at some selected sites in the Valleys of Zermatt and Arolla. Their frequency and intensity have been documented at different time scales by the application of a multi-method approach including webcam observations, terrestrial laser scanning measurements, GNSS surveys and photogrammetric analysis. At present, the project mostly aims at insuring the longer term monitoring of the sediment balance at the front of the rock glaciers that were previously investigated.

 

Collaborators:Reynald Delaloye (Professor), Hanne Hendrickx (PhD student) and formerly Mario Kummert (PhD thesis)

Contact: reynald.delaloye[at]unifr.ch

Duration: 2013-...

Study area: Valais (western Swiss Alps)

 

  • Illustrations

    Animation of the evolution of the surface elevation at the front of the Dirru rock glacier and in the gully downward in comparison to the initial state (26.06.2014). Surface lowering (red) represents erosion and surface uplift (blue) represent accumulation.

  • Publications

    • Kummert, M., Braillard, L., Delaloye, R., Bodin, X. (2021). Pluri-decadal evolution of rock glaciers surface velocity and its impact on sediment export rates towards high alpine torrents. Earth Surface Processes and Landforms, 46(15), 3213-3227. DOI: 10.1002/esp.5231

    • Guillemot, A., Helmstettler, A., Larose, E., Baillet, L., Garambois, S., Mayoraz, R., Delaloye, R. (2020). Seismic monitoring in the Gugla rock glacier (Switzerland): ambient noise correlation, microseismicity and modelling. Geophysical Journal International, ggaa097. DOI: 10.1093/gji/ggaa097

    • Kummert, M. & Delaloye, R. (2018). Regional-scale inventory of periglacial moving landforms connected to the torrential network system. Geographica Helvetica, 73, 357-371. DOI: 10.5194/gh-73-357-2018

    • Kummert, M. & Delaloye, R. (2018). Mapping and quantifying sediment transfer between the front of rapidly moving rock glaciers and torrential gullies. Geomorphology 309, 60-76. DOI: 10.1016/j.geomorph.2018.02.021

    • Kummert, M., Delaloye, R. and Braillard, L. (2018). Erosion and sediment transfer processes at the front of rapidly moving rock glaciers: systematic observations with automatic cameras in the western Swiss Alps. Permafrost and Periglacial Processes 29, 21-33. DOI: 10.1002/ppp.1960