Les éboulis et leur environnement géomorphologique autre que celui des glaciers rocheux(The talus and their geomorphological environment, except rock-glaciers)

Abstract“Whisky Glacier” on James Ross Island, Antarctic Peninsula, comprises anévéand clean ice trunk surrounded by an extensive area of debris-covered ice resembling a rock glacier. The debris-free trunk of the glacier abuts abruptly against the broad, totally debris-covered tongue at a number of concentric zones where debris-laden beds crop out at the surface in a manner similar to the “inner moraine” formations of many polar glaciers.Ice structures and foliation suggest that “Whisky Glacier” is a polythermal glacier which is wet-based under the debris-free zone, and dry-based under the debris-covered zone. It is surmised that the glacier sole crosses the freezing front close to where the basal debris beds are upwarped towards the surface. Here, basal water is confined, and freezes to the under side of the glacier in thick beds of regelation ice which are uplifted to the surface along with the debris-laden beds. Ablation losses effectively cease beneath the blanket of debris covering the tongue.The transition from wet-based to dry-based conditions at the glacier sole is a powerful mechanism for entraining debris into a glacier and, in the case of “Whisky Glacier”, for lifting debris to the surface. It is suggested that this may be a mechanism for forming some polar rock glaciers.

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Assessment of liquid and solid water storage in rock glaciers versus glacier ice in the Austrian Alps

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.149593 ◽

2021 ◽

pp. 149593

Author(s):

Thomas Wagner ◽

Simon Kainz ◽

Kay Helfricht ◽

Andrea Fischer ◽

Michael Avian ◽

...

Keyword(s):

Water Storage ◽

Austrian Alps ◽

Glacier Ice ◽

Rock Glaciers ◽

Solid Water

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Schmidt-hammer exposure-age dating (SHD) of rock glaciers in the Schöderkogel-Eisenhut area, Schladminger Tauern Range, Austria

The Holocene ◽

10.1177/0959683611430410 ◽

2011 ◽

Vol 22 (7) ◽

pp. 761-771 ◽

Cited By ~ 19

Author(s):

Matthias Rode ◽

Andreas Kellerer-Pirklbauer

Keyword(s):

Root Zone ◽

Age Dating ◽

Surface Velocity ◽

Schmidt Hammer ◽

Rock Glacier ◽

Relative Age ◽

Exposure Age ◽

Rock Glaciers ◽

Glacier Length ◽

Eastern Austria

Schmidt-hammer rebound values ( R-values) enable relative-age dating of landforms, with R-values relating to degree of weathering and therefore length of exposure. This method – recently termed as Schmidt-hammer exposure-age dating (SHD) – was applied to date five rock glaciers (size range, 0.01–0.12 km2) and one recent rockfall deposit at the study area Schöderkogel-Eisenhut, in the Schladminger Tauern Range (14°03′E, 47°15′N), Austria. The rock glaciers consist of gneiss or high metamorphic series of mica-schist that are comparable in their R-values. Four of them are relict (permafrost absent) and one is intact (containing patches of permafrost). On each of the five rock glaciers, SHD was carried out at 4–6 sites (50 measurements per site) along a longitudinal transect from the frontal ridge to the root zone. Results at all five rock glaciers are generally consistent with each other sharing statistically significant R-values along transects. The range between the highest and the lowest mean R-value at each of the five rock glaciers is 9.9–5.2. Using rock glacier length and surface velocity data from nearby sites, the rock glacier development must have lasted for several thousand years. Furthermore, by using SHD results from rock glaciers of known age from other sites in the region with comparable geology, approximate surface ages of 6.7–11.4 ka were estimated. This indicates long formation periods for all five rock glaciers. Our results suggest that many of the 1300 relict rock glaciers in central and eastern Austria were formed over a long period during the Lateglacial and Holocene period.

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Creep of frozen slopes and ice-filled rock joints under temperature variation

Canadian Journal of Civil Engineering ◽

10.1139/l05-112 ◽

2006 ◽

Vol 33 (6) ◽

pp. 719-725 ◽

Cited By ~ 9

Author(s):

Branko Ladanyi

Keyword(s):

Creep Behavior ◽

Large Scale ◽

Variable Temperature ◽

Theoretical Models ◽

Rock Joints ◽

Interface Problems ◽

Frozen Ground ◽

Rock Glaciers ◽

Rock Interface ◽

Creep Temperature

Owing to climate warming trends, there has been an increasing interest in recent years in the accelerating creep of rock glaciers and frozen slopes. In the field of glaciology, the creep of glaciers has been extensively studied, observed, and analyzed for more than 100 years. Many valuable and detailed theoretical models have been proposed through the years for simulating the creep behavior of glaciers. This synthesis paper has no intention of proposing another one. Its purpose is only to supply to these models a potential geotechnical background, borrowed from the connected fields of frozen ground mechanics, rock mechanics, and the mechanics of mixtures. In particular, this paper attempts to extend some known models of mechanical behavior of unfrozen soil and rock masses to masses containing ice and to apply these models to large-scale creep of ice–rock mixtures and ice–rock interface problems under variable temperature and stress conditions.Key words: ice, rock, mixture, rock joints, slope stability, creep, temperature.

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Identifying Ice-Rich Layers in Rock Glaciers Using Geophysics: A Case Study in the Andes

10.3997/2214-4609.202120064 ◽

2021 ◽

Author(s):

G. de Pasquale ◽

R. Valois ◽

S. MacDonell ◽

N. Schaefer

Keyword(s):

The Andes ◽

Rock Glaciers

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