scholarly journals Slow surge of Trapridge Glacier, Yukon Territory, Canada

2007 ◽  
Vol 112 (F3) ◽  
Author(s):  
Tom-Pierre Frappé ◽  
Garry K. C. Clarke
Keyword(s):  
Yukon Territory ◽  
Trapridge Glacier

Evidence for temporally varying "sticky spots" at the base of Trapridge Glacier, Yukon Territory, Canada

1999 ◽  
Vol 45 (150) ◽  
pp. 352-360 ◽  
Author(s):  
Urs H. Fischer ◽  
Garryk. KC Clarke ◽  
Heinz Blatter
Keyword(s):  
Yukon Territory ◽  
Trapridge Glacier

scholarly journals Creep Slump in Glacier Reservoirs—Theory and Experiment

1981 ◽  
Vol 27 (97) ◽  
pp. 393-406 ◽  
Author(s):  
E. M. Shoemaker
Keyword(s):  
Cycle Time ◽  
Large Amplitude ◽  
Laboratory Experiments ◽  
Yukon Territory ◽  
Wave Profile ◽  
Material Flows ◽  
Cold Surge ◽  
Trapridge Glacier ◽  
Theory And Experiment ◽  
Good Agreement

AbstractFrequently the reservoir region of a cold surge-type glacier has a temperate base, while in a region surrounding the reservoir the base is cold. We analyse the slump process in such a reservoir region— that is, the process whereby material flows toward the lower end of the region and forms a critical wave profile there. The model agrees qualitatively with observations of Trapridge Glacier, Yukon Territory, Canada, which is currently experiencing a critical pre-surge condition. Calculations based on the model give good agreement with the surge cycle time of Rusty Glacier, Yukon Territory. Laboratory experiments show that a large-amplitude slump-induced wave profile forms prior to a surge. Experimental surges were produced with velocity increases of order one hundred.

scholarly journals Radio Soundings On Trapridge Glacier, Yukon Territory,Canada

1975 ◽  
Vol 14 (70) ◽  
pp. 79-84 ◽  
Author(s):  
R. H. Goodman ◽  
G. K. C. Clarke ◽  
G. T Jarvis ◽  
S. G. Collins ◽  
Robert Metcalfe
Keyword(s):  
Rapid Change ◽  
Yukon Territory ◽  
Ice Thickness ◽  
Surface Slope ◽  
Glacier Surface ◽  
Water Collection ◽  
Trapridge Glacier

As part of a program to study surge-type glaciers, a radar-depth survey, using a frequency of 620 MHz, has been made of Trapridge Glacier, Yukon Territory. Soundings were taken at 26 locations on the glacier surface and a maximum ice thickness of 143 m was measured. A rapid change in surface slope in the lower ablation region marks the boundary between active and stagnant ice and is suggestive of an “ice dam” or the water “collection zone” postulated by Robin and Weertman for surging glaciers.

scholarly journals Surface and bed topography of Trapridge Glacier, Yukon Territory, Canada: digital elevation models and derived hydraulic geometry

1999 ◽  
Vol 45 (149) ◽  
pp. 165-174 ◽  
Author(s):  
Gwenn E. Flowers ◽  
Garry K. C. Clarke
Keyword(s):  
Digital Elevation Models ◽  
Water Pressure ◽  
Geometric Analysis ◽  
Radar Data ◽  
Yukon Territory ◽  
Bed Topography ◽  
Digital Elevation ◽  
Basin Scale ◽  
Hydrological System ◽  
Trapridge Glacier

AbstractMeasurements of ice thickness and surface elevation are prerequisite to many glaciological investigations. A variety of techniques has been developed for interpretation of these data, including means of constructing regularly gridded digital elevation models (DEMs) for use in numerical studies. Here we present a simple yet statistically sound method for processing ice-penetrating radar data and describe a technique for interpolating these data onto a regular grid. DEMs generated for Trapridge Glacier, Yukon Territory, Canada, are used to derive geometric quantities that give preliminary insights into the underlying basin-scale hydrological system. This simple geometric analysis suggests that at low water pressures a dendritic drainage network exists that evolves into a uniaxial morphology as water pressure approaches flotation. These predictions are compared to hydraulic connection probabilities based on borehole drilling.

scholarly journals Subglacial measurement of turbidity and electrical conductivity

1993 ◽  
Vol 39 (132) ◽  
pp. 415-420 ◽  
Author(s):  
Dan B. Stone ◽  
Garry K. C. Clarke ◽  
Erik W. Blake
Keyword(s):  
Electrical Conductivity ◽  
Water Flow ◽  
Yukon Territory ◽  
The Other ◽  
Potential Usefulness ◽  
Direct Measurements ◽  
Trapridge Glacier

AbstractDirect measurements of the properties of subglacial water are necessary for understanding water flow beneath glaciers. In this paper we describe the construction, calibration and field usage of two instruments—one that measures turbidity and the other that measures electrical conductivity of subglacial water. The sensors are inexpensive and reliable. To demonstrate the potential usefulness of these devices, we present samples of data obtained from beneath Trapridge Glacier, Yukon Territory, Canada.

scholarly journals Evidence for temporally varying “sticky spots” at the base of Trapridge Glacier, Yukon Territory, Canada

1999 ◽  
Vol 45 (150) ◽  
pp. 352-360 ◽  
Author(s):  
Urs H. Fischer ◽  
Garry K. C. Clarke ◽  
Heinz Blatter
Keyword(s):  
Water Pressure ◽  
Strong Support ◽  
Water Film ◽  
High Water ◽  
Yukon Territory ◽  
Basal Resistance ◽  
Model Calculations ◽  
Pressure Transducers ◽  
Glacier Ice ◽  
Trapridge Glacier

AbstractDuring the 1992 summer field season we installed arrays of “plough-meters” and water-pressure transducers beneath Trapridge Glacier. Yukon Territory, Canada, to study hydromechanical coupling at the ice–bed interface. Diurnal signals recorded with two of these ploughmeters appear to correlate with fluctuations in sub-glacial water pressure. These diurnal variations can be explained by changes in basal resistance to sliding as mechanical conditions at the bed vary temporally in response to changes in the subglacial hydrological system. We propose that a lubricating water film, associated with high water pressures, promotes glacier sliding, whereas low pressures cause increased basal drag resulting in “sticky” areas. Using a theoretical model, we analyze the sliding motion of glacier ice over a flat surface having variable basal drag and show that a consistent explanation can be developed. Results from our model calculations provide strong support for the existence of time-varying sticky spots which are associated with fluctuations in subglacial water pressure.

scholarly journals Clast collision frequency as an indicator of glacier sliding rate

1997 ◽  
Vol 43 (145) ◽  
pp. 460-466
Author(s):  
Urs Η. Fischer ◽  
Garry K. C. Clarke
Keyword(s):  
Collision Frequency ◽  
Yukon Territory ◽  
Mechanical Interaction ◽  
Liquid Dispersion ◽  
Trapridge Glacier ◽  
Solid Liquid ◽  
Good Agreement

AbstractThe mechanical interaction between a glacier and subglacial sediment can be observed using an instrumented rod that we refer to as the UBC ploughmeter. For clast-rich sediments, the rate of collision between clasts and a rod dragged through these sediments should be related to the glacier sliding rate. By assuming that proglacial measurements of sediment granulometry represent the subglacial granulometry of Trapridge Glacier, Yukon Territory, Canada, we have used ploughmeter results to obtain an estimated sliding rate of ∼45 mm d−1, in good agreement with known rates. In addition, for a subglacial material treated as a solid-liquid dispersion having a linear viscous rheology, the force of collision experienced by the rod should be proportional to the effective sediment viscosity. Our estimate of ∼2.0 × 1010 Pa s agrees well with previously, derived values.

scholarly journals Thermally controlled glacier surging

2001 ◽  
Vol 47 (159) ◽  
pp. 527-538 ◽  
Author(s):  
A. C. Fowler ◽  
Tavi Murray ◽  
F. S. L. Ng
Keyword(s):  
Simple Model ◽  
Wave Front ◽  
Thermal Regime ◽  
Thick Layer ◽  
Travelling Wave ◽  
Yukon Territory ◽  
Wave Fronts ◽  
Ice Flow ◽  
Trapridge Glacier ◽  
Travelling Wave Front

AbstractBakaninbreen in Svalbard and Trapridge Glacier in Yukon Territory, Canada, are two prominent examples of surging glaciers which are thought to be controlled by their thermal regime. Both glaciers have developed large bulges which have propagated forward as travelling wave fronts, and which are thought to divide relatively stagnant downstream cold-based ice from faster-moving warm-based upstream ice. Additionally, both glaciers are underlain by a wet, metres thick layer of deforming till. We develop a simple model for the cyclic surging behaviour of these glaciers, which interrelates the motion of the ice and till through a description of the subglacial hydrology. We find that oscillations (surges) can occur if the subglacial hydrological transmissivity is sufficiently low and the till layer is sufficiently thin, and we suggest that these oscillations are associated with the development and propagation of a travelling wave front down the glacier. We therefore interpret the travelling wave fronts on both Trapridge Glacier and Bakaninbreen as manifestations of surges. In addition, we find that the violence of the surge in the model is associated with the resistance to ice flow offered by undulations in the bed, and the efficiency with which occasional hydrological events can release water accumulated at the glacier sole.

scholarly journals Clast collision frequency as an indicator of glacier sliding rate

1997 ◽  
Vol 43 (145) ◽  
pp. 460-466 ◽  
Author(s):  
Urs Η. Fischer ◽  
Garry K. C. Clarke
Keyword(s):  
Collision Frequency ◽  
Yukon Territory ◽  
Mechanical Interaction ◽  
Liquid Dispersion ◽  
Trapridge Glacier ◽  
Solid Liquid ◽  
Good Agreement

AbstractThe mechanical interaction between a glacier and subglacial sediment can be observed using an instrumented rod that we refer to as the UBC ploughmeter. For clast-rich sediments, the rate of collision between clasts and a rod dragged through these sediments should be related to the glacier sliding rate. By assuming that proglacial measurements of sediment granulometry represent the subglacial granulometry of Trapridge Glacier, Yukon Territory, Canada, we have used ploughmeter results to obtain an estimated sliding rate of ∼45 mm d−1, in good agreement with known rates. In addition, for a subglacial material treated as a solid-liquid dispersion having a linear viscous rheology, the force of collision experienced by the rod should be proportional to the effective sediment viscosity. Our estimate of ∼2.0 × 1010Pa s agrees well with previously, derived values.

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