EGU2020-7266, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-7266
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

What makes a rock glacier? Insights into the structure and dynamics of an active rock glacier on the Tibetan Plateau

Johannes Buckel1, Eike Reinosch2, Nora Krebs3,4, Anne Voigtländer4, Michael Dietze4, Ruben Schroeckh5, Matthias Bücker1, and Andreas Hördt1
Johannes Buckel et al.
  • 1Institute for Geophysics and extraterrestrial Physics, Technical University of Braunschweig, Braunschweig, Germany (j.buckel@tu-braunschweig.de)
  • 2Institute of Geodesy and Photogrammetry, Technical University of Braunschweig, Braunschweig, Germany (e.reinosch@tu-braunschweig.de)
  • 3Institute of Geosciences, Potsdam University, Potsdam, Germany (nokrebs@uni-potsdam.de)
  • 4Geomorphology (Section 4.6), GFZ German Research Centre for Geosciences, Potsdam, Germany (avoigt@gfz-potsdam.de)
  • 5Institute for Geography and Geology, University of Greifswald, Greifswald, Germany (timon.schroeckh@stud.uni-greifswald.de)

Rock glaciers are typically regarded as periglacial features and their dynamics are supposed to be driven by ice content. Under ongoing global warming we expect these structures and dynamics to change and at least decay. This would be especially the case of rock glaciers in climate-sensitive high mountains of the Tibetan plateau, like in the Nyainqêntanglha range. Despite the similar past and present periglacial climatic conditions in this region, rock glaciers are only formed in a few, specific valleys. With this study, we aim to provide insights into the environmental conditions under which rock glaciers are formed and maintained, to be able to better understand how they will respond to changing boundary conditions, imposed by global warming.

To assess “what makes a rock glacier?” we studied such a feature in the Qugaqie basin, at 5500 m a.s.l. To describe the structure and the dynamics of this active rock glacier we applied several methods (geomorphological mapping, geophysics, remote sensing) and we incorporated catchment area properties such as geology, water and sediment sources. Mapping of the geomorphology, the geology and surface material properties characterizes the external structure of the rock glacier. The internal structure, like the active layer zone and the existence of ice, is described by electrical resistivity tomography (ERT). To investigate the surface dynamics of the rock glaciers, we quantify displacement rates using Interferometric Synthetic Aperture Radar (InSAR) time-series analysis. To gain insight to internal deformation dynamics we use environmental seismology, allowing for detection and location of crack signals within the rock glacier. The seismic network also allows tracking rock falls at the head scarp and continuously monitoring glaciofluvial patterns. We find that the singularity of the presence of the studied rock glacier is most likely related to a specific melange of the geological structures, former glaciation of the valley, catchment size and shape and especially water availability.

How to cite: Buckel, J., Reinosch, E., Krebs, N., Voigtländer, A., Dietze, M., Schroeckh, R., Bücker, M., and Hördt, A.: What makes a rock glacier? Insights into the structure and dynamics of an active rock glacier on the Tibetan Plateau, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7266, https://doi.org/10.5194/egusphere-egu2020-7266, 2020

Comments on the presentation

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Presentation version 1 – uploaded on 30 Apr 2020
  • CC1: Comment on EGU2020-7266, Coline Mollaret, 06 May 2020

    Thanks Johannes and Micha for your answers on the chat! (I agree it is a bit challenging to follow several ones in parallel...)
    I repeat them here for a better understanding:

    Johannes Buckel: "Yes we planning to localize and to derive temporal patterns. At the moment we can differentiate earthquakes, rockfalls from internal rockglacier signals. We hope to see that the internal signals are congruent with our climate station (precipitation/temperature data)."

    Michael Dietze: "yes all events will be located, at the surface and hopefully in 3D, so that we can get ideas on when things happen and where things happen. And what the role of different triggers and catchments may be."

    Very interesting, I am looking forward to seeing your future results!
    How long did the seismometers run? (and which month? I guess only in summer?)

    Thanks

    Coline Mollaret

    • AC1: Reply to CC1, Johannes Buckel, 06 May 2020

      Yes, thats a good point and a little bit disappoiting. The seismometers run only for three week. Tibet is not so easy as the alps for fieldwork

      • AC2: Reply to AC1, Johannes Buckel, 06 May 2020

        They run from the beginning of September until the end