Permafrost creep and rock glacier dynamics

Abstract

This review paper examines thermal conditions (active layer and permafrost), internal composition (rock and ice components), kinematics and rheology of creeping perennially frozen slopes in cold mountain areas. The aim is to assemble current information about creep in permafrost and rock glaciers from diverse published sources into a single paper that will be useful in studies of the flow and deformation of subsurface ice and their surface manifestations not only on Earth, but also on Mars. Emphasis is placed on quantitative information from drilling, borehole measurements, geophysical soundings, photogrammetry, laboratory experiments, etc. It is evident that quantitative holistic treatment of permafrost creep and rock glaciers requires consideration of: (a) rock weathering, snow avalanches and rockfall, with grain-size sorting on scree slopes; (b) freezing processes and ice formation in scree at sub-zero temperatures containing abundant fine material as well as coarse-grained blocks; (c) coupled thermohydro-mechanical aspects of creep and failure processes in frozen rock debris; (d) kinematics of non-isotropic, heterogeneous and layered, ice-rich permafrost on slopes with long transport paths for coarse surface material from the headwall to the front and, in some cases, subsequent re-incorporation into an advancing rock glacier causing corresponding age inversion at PERMAFROST AND PERIGLACIAL PROCESSES

Compilation of a glacier inventory for the western Himalayas from satellite data: methods, challenges, and results

“…In addition, these features are a mix of glacial and periglacial forms and simple differentiations between debris-covered glaciers and rock glaciers are even on-site not possible (e.g. Whalley et al, 1986;Haeberli et al, 2006). Some hints in interpreting these features are provided by the InSAR coherence images; however, not only glacier flow but also the movement of rockglaciers and other creeping features causes a loss of coherence (Fig.…”

Influence of surface and subsurface heterogeneity on observed borehole temperatures at a mountain permafrost site in the Upper Engadine, Swiss Alps

“…Since work on high altitude permafrost distribution started in the 1970s (Barsch, 1977;Haeberli et al, 1988), one of the challenging problems is the heterogeneity of mountain permafrost in terms of its microclimate, snow cover and subsurface material, which makes a direct comparison of different permafrost sites almost impossible. If this heterogeneity and its influence on the thermal regime of the permafrost is known, the accuracy of spatially distributed permafrost models based on topoclimatic factors could be verified.…”

“…Taking into account that the investigation of this area started in the 1970s (Barsch, 1977), it is now one of the best investigated permafrost areas in the Alps and part of the PERMOS network (Permafrost Monitoring Switzerland) (e.g. Haeberli et al, 1988;Hoelzle et al, 2002;Hanson and Hoelzle, 2005;PER-MOS, 2010). Within the area, the Murtèl rock glacier is one of the dominant periglacial features, but further rock glaciers and talus slopes are present to the west (Fig.…”

Investigating groundwater flow components in an Alpine relict rock glacier (Austria) using a numerical model

“…Rock glaciers in general are scree masses that are supersaturated with ice and gravitationally move downslope with velocities of a few centimeters up to several meters per year (e.g., Barsch 1996;Haeberli et al 2006). The size and shape of rock glaciers depends on climatic conditions, cirque geometry and debris supply of the comprising headwalls (Degenhardt 2009).…”

“…Investigations of rock glaciers mainly focus on the distribution, movement and the inner structure of intact rock glaciers (e.g., Haeberli et al 2006;Jansen and Hergarten 2006;Leopold et al 2011;Monnier et al 2011). Monnier and Kinnard (2015) investigated the internal structure of an active rock glacier in the Dry Andes with ground penetrating radar.…”