Glacier forefields in mountain permafrost environments
Glacier forefields located within the belt of discontinuous permafrost are complex systems sitting astride the glacial, paraglacial and periglacial research frontier. These recently deglaciated environments have been characterized as transient systems pursuing a state of equilibrium by adjusting to non-glacial conditions, and are therefore subject to intense geomorphological activity, especially under the current conditions of a warming climate (Bosson et al., 2014). Present-day landforms existing in these systems are legacies of the interrelations between glacial and periglacial morphodynamics and are therefore precious proxies for the understanding of the spatio-temporal evolution of permafrost in glacier forefield systems.
In a first step, this project aims at inventorying LIA glacier forefields within the belt of permafrost in the western Swiss Alps where mass-wasting processes occur, as “there is an urgent need for inventories of proglacial systems, to form a baseline from which changes could be detected” (Carrivick and Heckmann, 2017: 22). The description of their structure (or geomorphological configuration) and consequently, the associated geomorphological sequences observed in these systems will allow the acquisition of further insight on the development of LIA glacier forefield systems in mountain permafrost environments, as well as the physical processes involved in their development and evolution. In the continuity of this scope of research, the assessment of the spatio-temporal evolution of permafrost in proglacial systems would allow a better understanding of their geomorphic activity. To fulfil the main objectives of this proposed research, investigations will be led according to the following main research questions:
- What are the observed types of geomorphological sequences occurring in LIA glacier forefield systems located within the belt of permafrost where mass-wasting processes are observed?
- What are the processes behind these configurations?
- How does the spatial distribution of permafrost/ground ice influence the dynamics of glacier forefield systems?
- How has permafrost/ground ice evolved since the last decades in LIA glacier forefield systems and what are the consequences of the evolution of permafrost on the dynamics of these systems?
- How do glaciers and permafrost evolve in glacier forefield systems? And how do these changes affect their interactions?
To address these questions, the analysis of interferometric synthetic aperture radar (InSAR) data and aerial photographs (ortho-images) will provide information to identify and describe (inventory) LIA glacier forefields within the belt of discontinuous permafrost in the western Swiss Alps where mass-wasting processes occur. In a further step, the analysis of existing geoelectrical surveys and their repetition will allow the assessment of the spatial distribution and the thermal evolution of permafrost/ground ice in these glacier forefield systems. Moreover, repeated LiDAR seasonal/annual measurements will complete this analysis, as the data will allow capturing surface changes, consequently the processes behind the dynamics of glacier forefields.
Collaborators: Julie Wee (PhD student), Reynald Delaloye (Professor)
Duration: 2019 - 2023
Study area: Valais (western Swiss Alps)