An experimental design for laboratory simulation of periglacial solifluction processes

Harris, Charles; Davies, M. C. R.; Coutard, Jean‐Pierre

doi:10.1002/(sici)1096-9837(199601)21:1<67::aid-esp544>3.0.co;2-y

Cited by 22 publications

(4 citation statements)

References 5 publications

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“…Previous experiments have shown the influence of frost weathering on (i) rock fracturing and brecciation enhanced by ice segregation in permafrost (Murton et al, 2001); (ii) thaw-related gelifluction (Harris et al, 1995(Harris et al, , 1996(Harris et al, , 2003; and (iii) sliding of cryoclasts on an experimental slope (Calmels and Coutard, 2000).…”

Section: Physical Modelling Of Scarp Erosion During Periglacial Stagesmentioning

confidence: 99%

Physical modelling of fault scarp degradation under freeze–thaw cycles

Font

Lagarde

Amorèse

et al. 2006

Earth Surf Processes Landf

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Physical modelling has been developed in order to simulate the effects of periglacial erosion processes on the degradation of slopes and scarps. Data from 41 experimental freeze-thaw cycles are presented. They attest to the efficiency of periglacial processes that control both erosion and changes in scarp morphology: (i) cryoexpulsion leads to an increase of scarp surface roughness and modifies significantly the internal structure of the active layer; (ii) combined effects of frost creep and gelifluction lead to slow and gradual downslope displacements of the active layer (0·3 cm/cycle); (iii) debris flows are associated with the most significant changes in scarp morphology and are responsible for the highest rate of scarp erosion; (iv) quantification of the erosion rate gives values close to 1 cm 3 cm − − − − −2 for 41 freeze-thaw cycles. These experimental results are consistent with field data acquired along the La Hague fault scarp (Normandy, France) where an erosion rate of 4·6 ± ± ± ± ± 1 m 3 m − − − − −2 per glacial stage has been computed from the volume of natural slope deposits stored during the Weichselian glacial stage. These results show that moist periglacial erosion processes could lead to an underestimation of Plio-Quaternary deformation in the mid-latitudes. CopyrightEvidence of erosion and decay of a scarp can be found along the la Hague Fault Zone ( Figure 1A). In this metamorphic basement area, detailed analyses of the scarp morphology and slope deposits have allowed identification of periglacial processes (Elhaï, 1963;Watson and Watson, 1970;Lautridou, 1985;Font, 2002).Cryoclastic processes that occurred during periglacial periods have contributed to the fracturing of metamorphic rocks near the surface, leading to a widespread cover of cryoclasts.Downslope sliding of cryoclasts is indicated by footslope deposits several tens of metres thick (Elhaï, 1963;Watson and Watson, 1970). Slope deposits are roughly stratified and made of coarse angular metamorphic and sedimentary rocks, which come from the Palaeozoic units exposed in the slope above (Watson and Watson, 1970). The slope deposits lie on a raised beach and show distinctive geometrical and lithological characteristics: (i) along the scarp, variations of the lithology follow variations of the bedrock on the back slope; (ii) the stratification is characterized by Fault scarp degradation 1733 Figure 6. (A) Displacement profiles of lateral tile columns indicating the continuous deformation of the active layer during thawing. One can note that higher values of displacement are measured in the lower part of the scarp. (B) Cumulated displacements of the top tiles from central columns. (C) Quantification of slope deposits translated during the continuous deformation of the active layer (lateral downstream tile column).Figure 8. Progressive changes in scarp morphology: H, heaving; P, packing; He, headward erosion; Ab, ablation due to debris flows.Figure 9. Correlation between slope variations and volume changes on the basal steeper slope: 1, progre...

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Section: Physical Modelling Of Scarp Erosion During Periglacial Stagesmentioning

confidence: 99%

Physical modelling of fault scarp degradation under freeze–thaw cycles

Font

Lagarde

Amorèse

et al. 2006

Earth Surf Processes Landf

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“…Instrumentation included semiconductor temperature sensors and thermistor arrays to monitor soil temperatures, Druck miniature pore pressure transducers filled with antifreeze to monitor porewater pressures, and linear voltage displacement transformers (LVDTs) to monitor frost heave and downslope soil displacement (Harris et al, 1996). Instruments were scanned at half-hourly intervals using a PC-controlled data logging system.…”

Section: Experimental Design and Instrumentationmentioning

confidence: 99%

“…Soil temperatures, porewater pressures and slope movements were monitored at halfhourly intervals using a PC logging system. The experimental design has been described in detail by Harris et al (1996) and results of porewater pressure measurements during soil thawing and their analysis in the context of slope stability are discussed in Harris et al (1995). Here we present data on frost heave and downslope soil displacements and discuss factors influencing movement rates and mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Rates and processes of periglacial solifluction: an experimental approach

Harris

Davies

Coutard

1997

Earth Surf. Process. Landforms

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Cold room physical modelling of periglacial solifluction processes on an experimental slope of 12° is described, and data on soil temperatures, surface frost heave, thaw consolidation, downslope soil movement and porewater pressures over seven freeze-thaw cycles are presented. These data are analyzed in the context of laboratory determination of the rheometry of the experimental soils at high moisture contents. It is concluded that the observed thaw-induced solifluction represents prefailure soil shear strain and results from loss of strength due to the combined effects of raised porewater pressures during thaw consolidation and upward seepage pressures as water flows towards the surface away from the thaw front. An investigation of the rheometry of thawing soils offers the prospect of an analytical model to predict rates and depths of periglacial solifluction.

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“…This therefore reduces soil shear strength, allowing it to deform downslope under its own weight. Finally, slope gradient must be steep enough to initiate downslope self‐weight shear stresses but not too steep as this can cause failure along a shear plane or generate a debris flow …”

Section: Discussionmentioning

confidence: 99%

Supervised classification of landforms in Arctic mountains

Mithan

Hales

Cleall

2019

Permafrost & Periglacial

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Erosional and sediment fluxes from Arctic mountains are lower than for temperate mountain ranges due to the influence of permafrost on geomorphic processes. As permafrost extent declines in Arctic mountains, the spatial distribution of geomorphic processes and rates will change. Improved access to high‐quality remotely sensed topographic data in the Arctic provides an opportunity to develop our understanding of the spatial distribution of Arctic geomorphological processes and landforms. Utilizing newly available Arctic digital topography data, we have developed a method for geomorphic mapping using a pixel‐based linear discriminant analysis method that could be applied across Arctic mountains. We trained our classifier using landforms within the Adventdalen catchment in Svalbard and applied it to two adjacent catchments and one in Alaska. Slope gradient, elevation–relief ratio and landscape roughness distinguish landforms to a first order with >80% accuracy. Our simple classification system has a similar overall accuracy when compared across our field sites. The simplicity and robustness of our classification suggest that it is possible to use it to understand the distribution of Arctic mountain landforms using extant digital topography data and without specialized classifications. Our preliminary assessments of the distribution of geomorphic processes within these catchments demonstrate the importance of post‐glacial hillslope processes in governing sediment movement in Arctic mountains.

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An experimental design for laboratory simulation of periglacial solifluction processes

Cited by 22 publications

References 5 publications

Physical modelling of fault scarp degradation under freeze–thaw cycles

Physical modelling of fault scarp degradation under freeze–thaw cycles

Rates and processes of periglacial solifluction: an experimental approach

Supervised classification of landforms in Arctic mountains

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