Internal Structure and Current Evolution of Very Small Debris-Covered Glacier Systems Located in Alpine Permafrost Environments

Abstract

This contribution explores the internal structure of very small debris-covered glacier systems located in permafrost environments and their current dynamical responses to short-term climatic variations. Three systems were investigated with electrical resistivity tomography and dGPS monitoring over a 3-year period. Five distinct sectors are highlighted in each system: firn and bare-ice glacier, debris-covered glacier, heavily debris-covered glacier of low activity, rock glacier and ice-free debris. Decimetric to metric movements, related to ice ablation, internal deformation and basal sliding affect the glacial zones, which are mainly active in summer. Conversely, surface lowering is close to zero (−0.04 m yr −1 ) in the rock glaciers. Here, a constant and slow internal deformation was observed (c. 0.2 m yr −1 ). Thus, these systems are affected by both direct and high magnitude responses and delayed and attenuated responses to climatic variations. This differential evolution appears mainly controlled by (1) the proportion of ice, debris and the presence of water in the ground, and (2) the thickness of the superficial debris layer.

Global glacier volume projections under high-end climate change scenarios

“…inefficient sediment evacuation eventually leads to the transition from debris-covered glaciers to rock glaciers (e.g (Monnier and Kinnard 2017). In the context of continued climate warming, the transition from ice glaciers to rock glaciers may enhance the resilience of the mountain cryosphere (Bosson and Lambiel 2016). As a result, better assessment of the response of the mountain cryosphere to climate warming will depend on a clearer understanding of glacier-rock glacier relationships.…”

Decadal evolution of a very small heavily debris-covered glacier in an Alpine permafrost environment

“…Like other similar systems (Bosson and others, 2015;Micheletti and others, 2015a), Tsarmine is disconnected from downslope sediment transfer systems because of the presence of the moraine dam and the rock glacier, the relatively weak slope angle (17°of mean slope for the longitudinal profile between the top of the glacier and the top of the moraine dam), the reduced magnitude of sediment transfer processes and the absence of a proglacial meltwater stream. Bosson and Lambiel (2016) quantified the surface kinematics of the Tsarmine system between 2011 and 2014 with repeated dGPS measurements. The results highlighted the existence of different dynamic behaviours at annual and seasonal timescales between zones 2b, 3, 4 and 5.…”

Occurrence, evolution and ice content of ice‐debris complexes in the Ak‐Shiirak, Central Tien Shan revealed by geophysical and remotely‐sensed investigations

“…Similar large complex ice‐debris landforms are equally common in the dry Andes (Bodin et al, ; Falaschi et al, ; Monnier et al, ) but detailed investigations are still quite limited. Rock glaciers that interact with glaciers also exist in the European Alps although they are smaller in size (Kääb et al, ; Dusik et al, ; Bosson and Lambiel, ; Capt et al, ).…”