10th International Conference on Geomorphology
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Large landslides are concentrated along Patagonian Ice Sheet margin

Michal Břežný1, Tomáš Pánek1, Stephan Harrison2, Elisabeth Schönfeldt3, and Diego Winocur4
Michal Břežný et al.
  • 1University of Ostrava, Department of Physical Geography and Geoecology, Chittussiho 10, Slezská Ostrava, Czech Republic
  • 2College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Treliever Road, Penryn TR10 9FE, United Kingdom of Great Britain and Northern Ireland
  • 3University of Potsdam, Institute of Geosciences, Karl-Liebknecht-Straße 24-25, 14476, Potsdam, Germany
  • 4Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Ciencias Geologicas, Intendente Güiraldes 2416, C1428EGA, CABA, Argentina

Deglaciation of mountain ranges promotes landslides of various scales and types, and many of them may present a major hazard. It is commonly thought that the main concentration of landslides is located in parts of the mountain ranges that have pronounced topography, high amount of precipitation and strong tectonic activity. Based on our mapping of large landslides (>1km2) over an extensively large area of Southern Patagonia (~305,000 km²), we show that the distribution of landslides can have the opposite character. The largest landslides within the limits of the former Patagonian Ice Sheet (PIS) are concentrated along its eastern margins and thus occupying lower, tectonically less active, and arid part of the Patagonian Andes. In contrast to the heavily glaciated, highest elevations of the mountain range, the peripheral regions have been glaciated only episodically. However, a combination of glaciation, weak volcanic and sedimentary rocks, sufficient relief, and presence of large glacial lakes in the past, created favourable conditions for formation of huge number of large landslides along eastern margin of PIS. We explain the scarcity of large landslides in the highest parts of the PIS by presence of strong granitic rocks and long-term glacial modification, that adjusted topography for efficient ice discharge. Our model is limited to large bedrock landslides as shallow slides and rock falls are abundant in the highest and western part of the Andes.

How to cite: Břežný, M., Pánek, T., Harrison, S., Schönfeldt, E., and Winocur, D.: Large landslides are concentrated along Patagonian Ice Sheet margin, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-141, https://doi.org/10.5194/icg2022-141, 2022.