Development of tongue-shaped and multilobate rock glaciers in alpine environments – Interpretations from ground penetrating radar surveys

Degenhardt, J. J.

doi:10.1016/j.geomorph.2009.02.020

Cited by 78 publications

(57 citation statements)

References 57 publications

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“…Here, it is important to recall and highlight the differences between both types of landforms (Nakawo et al, 2000;Kääb and Weber, 2004;Haeberli et al, 2006;Degenhardt, 2009;Benn and Evans, 2010;Berthling, 2011;Cogley et al, 2011). Rock glaciers are perennially frozen homo-or heterogeneous ice-rock mixtures covered with a continuous and severalmetre-thick ice-free debris layer that thaws every summer (known as the permafrost "active layer"); rock glacier movement is governed by gravity-driven permafrost creep.…”

Section: Evolution Of Glacier-rock Glacier Transitional Landformsmentioning

confidence: 99%

Pluri-decadal (1955–2014) evolution of glacier–rock glacier transitional landforms in the central Andes of Chile (30–33° S)

Monnier

Kinnard

2017

Earth Surf. Dynam.

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Abstract. Three glacier-rock glacier transitional landforms in the central Andes of Chile are investigated over the last decades in order to highlight and question the significance of their landscape and flow dynamics. Historical (1955Historical ( -2000 aerial photos and contemporary (> 2000) Geoeye satellite images were used together with common processing operations, including imagery orthorectification, digital elevation model generation, and image feature tracking. At each site, the rock glacier morphology area, thermokarst area, elevation changes, and horizontal surface displacements were mapped. The evolution of the landforms over the study period is remarkable, with rapid landscape changes, particularly an expansion of rock glacier morphology areas. Elevation changes were heterogeneous, especially in debris-covered glacier areas with large heaving or lowering up to more than ±1 m yr −1 . The use of image feature tracking highlighted spatially coherent flow vector patterns over rock glacier areas and, at two of the three sites, their expansion over the studied period; debris-covered glacier areas are characterized by a lack of movement detection and/or chaotic displacement patterns reflecting thermokarst degradation; mean landform displacement speeds ranged between 0.50 and 1.10 m yr −1 and exhibited a decreasing trend over the studied period. One important highlight of this study is that, especially in persisting cold conditions, rock glaciers can develop upward at the expense of debris-covered glaciers. Two of the studied landforms initially (prior to the study period) developed from an alternation between glacial advances and rock glacier development phases. The other landform is a small debris-covered glacier having evolved into a rock glacier over the last half-century. Based on these results it is proposed that morphological and dynamical interactions between glaciers and permafrost and their resulting hybrid landscapes may enhance the resilience of the mountain cryosphere against climate change.

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Section: Evolution Of Glacier-rock Glacier Transitional Landformsmentioning

confidence: 99%

Pluri-decadal (1955–2014) evolution of glacier–rock glacier transitional landforms in the central Andes of Chile (30–33° S)

Monnier

Kinnard

2017

Earth Surf. Dynam.

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“…While penetration depth increases at low frequencies, the depth resolution decreases. Frequencies between 6.4 and 250 MHz have been used to measure thickness of up to about 40 m and internal properties of rock glaciers in the Alps, the polar regions, and the United States (Fukui et al, 2007;Degenhardt, 2009;Degenhardt et al, 2003;Nickus et al, 2015).…”

Section: Gprmentioning

confidence: 99%

Can a simple Numerical Model Help to Fine-Tune the Analysis of Ground-Penetrating Radar Data? Hochebenkar Rock Glacier as a Case Study

Hartl

Fischer

Klug

et al. 2016

Arctic, Antarctic, and Alpine Research

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“…The size and shape of rock glaciers depends on climatic conditions, cirque geometry and debris supply of the comprising headwalls (Degenhardt 2009). Therefore, the range in size is highly variable (e.g., KellererPirklbauer et al 2012;Krainer and Ribis 2012).…”

Section: Introductionmentioning

confidence: 99%

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

Pauritsch¹,

Wagner

Winkler

et al. 2016

Hydrogeol J

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Relict rock glaciers are complex hydrogeological systems that might act as relevant groundwater storages; therefore, the discharge behavior of these alpine landforms needs to be better understood. Hydrogeological and geophysical investigations at a relict rock glacier in the Niedere Tauern Range (Austria) reveal a slow and fast flow component that appear to be related to the heterogeneous structure of the aquifer. A numerical groundwater flow model was used to indicate the influence of important internal structures such as layering, preferential flow paths and aquifer-base topography. Discharge dynamics can be reproduced reasonably by both introducing layers of strongly different hydraulic conductivities or by a network of highly conductive channels within a low-conductivity zone. Moreover, the topography of the aquifer base influences the discharge dynamics, which can be observed particularly in simply structured aquifers. Hydraulic conductivity differences of three orders of magnitude are required to account for the observed discharge behavior: a highly conductive layer and/or channel network controlling the fast and flashy spring responses to recharge events, as opposed to less conductive sediment accumulations sustaining the long-term base flow. The results show that the hydraulic behavior of this relict rock glacier and likely that of others can be adequately represented by two aquifer components. However, the attempt to characterize the two components by inverse modeling results in ambiguity of internal structures when solely discharge data are available.

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Development of tongue-shaped and multilobate rock glaciers in alpine environments – Interpretations from ground penetrating radar surveys

Cited by 78 publications

References 57 publications

Pluri-decadal (1955–2014) evolution of glacier–rock glacier transitional landforms in the central Andes of Chile (30–33° S)

Pluri-decadal (1955–2014) evolution of glacier–rock glacier transitional landforms in the central Andes of Chile (30–33° S)

Can a simple Numerical Model Help to Fine-Tune the Analysis of Ground-Penetrating Radar Data? Hochebenkar Rock Glacier as a Case Study

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

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