Structure and genesis of the Thabor rock glacier (Northern French Alps) determined from morphological and ground-penetrating radar surveys

Monnier, Sébastien; Camerlynck, Christian; Réjiba, Fayçal; Kinnard, Christophe; Feuillet, Thierry; Dhemaïed, A.

doi:10.1016/j.geomorph.2011.07.004

Cited by 44 publications

(41 citation statements)

References 22 publications

(24 reference statements)

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“…The occurrence of such structures in the root zone of rock glaciers is a well-known phenomenon which develops from buried snow banks or ice patches which were incorporated into the subsurface, e.g. by rockfall (Monnier et al, 2011;Lugon et al, 2004;Isaksen et al, 2000;Haeberli and Vonder Mühll, 1996). A high geomorphological activity is present at Nair rock glacier where frequent rockfall events were observed during several field campaigns.…”

Section: Structure Of Nair Rock Glaciermentioning

confidence: 99%

Internal structure of two alpine rock glaciers investigated by quasi-3-D electrical resistivity imaging

Emmert

Kneisel

2017

The Cryosphere

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Abstract. Interactions between different formative processes are reflected in the internal structure of rock glaciers. Therefore, the detection of subsurface conditions can help to enhance our understanding of landform development. For an assessment of subsurface conditions, we present an analysis of the spatial variability of active layer thickness, ground ice content and frost table topography for two different rock glaciers in the Eastern Swiss Alps by means of quasi-3-D electrical resistivity imaging (ERI). This approach enables an extensive mapping of subsurface structures and a spatial overlay between site-specific surface and subsurface characteristics. At Nair rock glacier, we discovered a gradual descent of the frost table in a downslope direction and a constant decrease of ice content which follows the observed surface topography. This is attributed to ice formation by refreezing meltwater from an embedded snow bank or from a subsurface ice patch which reshapes the permafrost layer. The heterogeneous ground ice distribution at Uertsch rock glacier indicates that multiple processes on different time domains were involved in the development. Resistivity values which represent frozen conditions vary within a wide range and indicate a successive formation which includes several advances, past glacial overrides and creep processes on the rock glacier surface. In combination with the observed topography, quasi-3-D ERI enables us to delimit areas of extensive and compressive flow in close proximity. Excellent data quality was provided by a good coupling of electrodes to the ground in the pebbly material of the investigated rock glaciers. Results show the value of the quasi-3-D ERI approach but advise the application of complementary geophysical methods for interpreting the results.

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Section: Structure Of Nair Rock Glaciermentioning

confidence: 99%

Internal structure of two alpine rock glaciers investigated by quasi-3-D electrical resistivity imaging

Emmert

Kneisel

2017

The Cryosphere

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“…A reliable interpretation of small-scale geophysical anomalies (or their temporal changes) remains, therefore, difficult (Hilbich et al, 2009). Current challenges for the application of geophysical methods to rock glaciers include (a) the resolution potential for small-scale anomalies and processes (ideally down to the depth of the shear horizon at 15-20 m or more), and (b) the delineation of the complex internal structure and the quantification of the overall ice/water content in a rock glacier (Maurer and Hauck, 2007;Monnier et al, 2011;Monnier and Kinnard, 2013;Hausmann et al, 2007;Merz et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Resolution capacity of geophysical monitoring regarding permafrost degradation induced by hydrological processes

et al. 2017

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Abstract. Geophysical methods are often used to characterize and monitor the subsurface composition of permafrost. The resolution capacity of standard methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement geometry, but also on the temporal variability in the contrast of the geophysical target variables (electrical resistivity and P-wave velocity). Our study analyses the resolution capacity of electrical resistivity tomography and refraction seismic tomography for typical processes in the context of permafrost degradation using synthetic and field data sets of mountain permafrost terrain. In addition, we tested the resolution capacity of a petrophysically based quantitative combination of both methods, the so-called 4-phase model, and through this analysed the expected changes in water and ice content upon permafrost thaw. The results from the synthetic data experiments suggest a higher sensitivity regarding an increase in water content compared to a decrease in ice content. A potentially larger uncertainty originates from the individual geophysical methods than from the combined evaluation with the 4-phase model. In the latter, a loss of ground ice can be detected quite reliably, whereas artefacts occur in the case of increased horizontal or vertical water flow. Analysis of field data from a well-investigated rock glacier in the Swiss Alps successfully visualized the seasonal ice loss in summer and the complex spatially variable ice, water and air content changes in an interannual comparison.

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“…Rock glaciers usually have a thickness in the order of several tens of meters. Monnier et al (2011) and Monnier and Kinnard (2015) used ground pene trating radar to investigate two active rock glaciers in the French Alps and Chilean Andes. Their results suggest a heterogeneous, layered inner structure of the rock glacier which is in good agreement with the findings of Hausmann et al (2012) at intact rock glaciers in the Austrian Alps based on surface geophysical investigation methods.…”

Section: Introductionmentioning

confidence: 99%

Impact of relict rock glaciers on spring and stream flow of alpine watersheds: Examples of the Niedere Tauern Range, Eastern Alps (Austria)

Wagner¹,

Pauritsch²,

Winkler³

2016

AJES

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In crystalline mountain regions, relict rock glaciers are apparent sediment accumulations that likely influence the runoff in alpine watersheds as a result of their discharge behavior. However, little is known about their impact on the streamflow further downstream. More than 560 mostly relict rock glacier-related landforms have been identified in the Styrian part of the Niedere Tauern Range (Austria). The catchment of a single relict rock glacier (Schöneben Rock Glacier, SRG), and two catchments with relict rock glaciers in their headwaters were investigated with a simple lumped-parameter rainfall-runoff model. The model parameters of the SRG catchment are in agreement with the existing conceptual understanding of the discharge dynamics and provide the parameter configuration to simulate the runoff of ungauged relict rock glacier catchments in the area. In addition, a semi-distributed approach was applied to quantify the impact of relict rock glacier-influenced headwaters on the downstream runoff. The results suggest that the contribution ranges from about a quarter to more than four times its areal share. The highest impact is observed during the late snow melt period and in the late summer. This highlights the relevance of these sediment accumulations in relation to water manage ment issues, in particular concerning altering meteorological conditions due to climate change.Reliktische Blockgletscher sind augenscheinliche Sedimentanhäufungen in kristallinen Gebirgsregionen, die aufgrund ihrer Abflussdynamik die Entwässerung alpiner Einzugsgebiete beeinflussen. Jedoch ist ihre Auswirkung auf unterstromige Gerinne weitgehend unbekannt. Mehr als 560 meist reliktische Blockgletscher sind im Steirischen Anteil der Niederen Tauern (Österreich) ausgewiesen. Ein über einen reliktischen Blockgletscher (Schöneben Blockgletscher, SRG) entwässerndes Einzugsgebiet und zwei Einzugsgebiete, die ihrerseits reliktische Blockgletscher in ihren hoch gelegenen Anteilen beinhalten, wurden mit Hilfe eines einfachen, räumlich nicht aufgelösten (lumped Parameter) Niederschlags-Abflussmodells untersucht. Die Modellparameter des SRG-Einzugsgebiets stimmen mit dem vorliegenden konzeptionellen Modell überein und dienen als Grundlage der Parameterkonfiguration zur Abflusssimulation anderer Blockgletschereinzugsgebiete in der Region, für die keine Abflussdaten zur Verfügung stehen. Zusätzlich wurde ein semi-distributiver Ansatz angewendet, um den Einfluss von Blockgletscher beeinflussten Einzugsgebieten auf die unterstromigen Gerinne zu quantifizieren. Die Ergebnisse zeigen, dass der Abflussanteil unterstromig von einem Viertel bis zu mehr als dem Vierfachen des Flächenanteils der übergeordneten Einzugsgebiete beträgt. Die höchsten Anteile können gegen Ende der Schneeschmelze und im Spätsommer beobachtet werden. Dies unterstreicht die wasserwirtschaftliche Bedeutung dieser Schuttakkumulationen in alpinen Einzugsgebieten, vor allem unter der Berücksichtigung der sich ändernden meteorologischen Bedingungen im Zuge des Klimawandels.

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Structure and genesis of the Thabor rock glacier (Northern French Alps) determined from morphological and ground-penetrating radar surveys

Cited by 44 publications

References 22 publications

Internal structure of two alpine rock glaciers investigated by quasi-3-D electrical resistivity imaging

Internal structure of two alpine rock glaciers investigated by quasi-3-D electrical resistivity imaging

Resolution capacity of geophysical monitoring regarding permafrost degradation induced by hydrological processes

Impact of relict rock glaciers on spring and stream flow of alpine watersheds: Examples of the Niedere Tauern Range, Eastern Alps (Austria)

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