Flow, thermal structure, and subglacial conditions of a surge-type glacier

Clarke, Garry K. C.; Collins, Sam G.; Thompson, David E.

doi:10.1139/e84-024

Cited by 277 publications

(297 citation statements)

References 28 publications

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“…Trapridge Glacier, Canada; Clarke et al, 1984). On Zawadzkibreen a visible bulge formed in stage 2 (Fig.…”

Section: Glacier Surface Expressionsmentioning

confidence: 99%

“…Towards the end of stage 2 or early in stage 3, large amounts of englacial water are released, as described by Lingle and Fatland (2003). At this stage, in addition to sliding, fast flow could also arise from deformation of saturated subglacial sediments, which can accommodate an inefficient drainage system (Clarke et al, 1984;Murray et al, 2000;Harrison and Post, 2003).…”

Section: Mass Transfer and Velocities During Surge (Stages 1-3)mentioning

confidence: 99%

“…Surges are found both in land-and tidewater-terminating glaciers as well as temperate and polythermal ones. (Meier and Post, 1969;Dolgoushin and Osipova, 1975;Clarke et al, 1984;Cuffey and Patterson, 2010). Based on studies from the temperate Variegated Glacier, Alaska, a hydraulic mechanism was proposed where surges are explained by switches between an efficient tunnel-based basal drainage system and slow linked-cavity system (Kamb et al, 1985;Kamb, 1987).…”

Section: Introductionmentioning

confidence: 99%

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Surge dynamics in the Nathorstbreen glacier system, Svalbard

2014

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Abstract. Nathorstbreen glacier system (NGS) recently experienced the largest surge in Svalbard since 1936, and this was examined using spatial and temporal observations from DEM differencing, time series of surface velocities from satellite synthetic aperture radar (SAR) and other sources. The upper basins with maximum accumulation during quiescence corresponded to regions of initial lowering. Initial speed-up exceeded quiescent velocities by a factor of several tens. This suggests that polythermal glacier surges are initiated in the temperate area before mass is displaced downglacier. Subsequent downglacier mass displacement coincided with areas where glacier velocity increased by a factor of 100-200 times (stage 2). After more than 5 years, the joint NGS terminus advanced abruptly into the fjord during winter, increasing velocities even more. The advance was followed by up-glacier propagation of crevasses, indicating the middle and subsequently the upper part of the glaciers reacting to the mass displacement. NGS advanced ∼15 km, while another ∼3 km length was lost due to calving. Surface lowering of ∼50 m was observed in some up-glacier areas, and in 5 years the total glacier area increased by 20 %. Maximum measured flow rates were at least 25 m d −1 , 2500 times quiescent velocity, while average velocities were about 10 m d −1 . The surges of Zawadzkibreen cycle with ca. 70-year periods.

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“…Trapridge Glacier, Canada; Clarke et al, 1984). On Zawadzkibreen a visible bulge formed in stage 2 (Fig.…”

Section: Glacier Surface Expressionsmentioning

confidence: 99%

Section: Mass Transfer and Velocities During Surge (Stages 1-3)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Surge dynamics in the Nathorstbreen glacier system, Svalbard

2014

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“…About 57% of Brdsvellbreen and significant parts of Etonbreen and S0re Franklinbreen lie below present sealevel (Dowdeswell and others, 1986). They are therefore likely to be underlain by deformable sediments, impl ying that a surge mechanism similar to that of Clarke and others (1984) may be operating on these Svalbard sub-polar ice masses. More data on the nature of the ice-substrate interface in specific drainage basins are required, however, to test the applicability of this theory of glacier surging in Nordaustlandet.…”

Section: Surging Drainage Basinsmentioning

confidence: 98%

Drainage-Basin Characteristics of Nordaustlandet Ice Caps, Svalbard

Dowdeswell

1986

J. Glaciol.

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Recent mapping of ice-surface and bedrock topography from airborne radio-echo sounding has shown that the ice caps of Nordaustlandet, Svalbard, are divided into a series of well-defined drainage basins. Three lines of evidence indicate that several distinctive modes of ice-flow regime characterize these basins: (1) comparison between observed and theoretical ice-surface profiles; (2) analysis of driving stresses; and (3) observations of ice-surface features on satellite imagery and air photographs. The drainage basins are inferred to behave in the following ways. First, basins with low driving stresses and surface profiles, some of them clearly stagnant, are associated with the quiescent phase between glacier surges. Secondly, the ice streams draining southern Vestfonna have low surface profiles, relatively low driving stresses, and marked shear zones at their margins. They are interpreted to be flowing continuously at a relatively faster rate than the ridges between them. Basal melting, perhaps combined with substrate deformation, is probably responsible for the regime of these glaciers. Thirdly, the remaining basins studied on Nordaustlandet have relatively high marginal driving stresses and high surface profiles. They are interpreted to be frozen to their beds, at least near their margins. Some of these basins may also surge, particularly those where a part of the basin is below sea-level, and therefore is probably underlain by considerable thicknesses of deformable sediments.

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“…Based on aerial observations of several glaciers in surge, Post (unpublished) developed ideas on the role of high-pressure water at the glacier bed in causing rapid sliding during a surge. The detailed observations of Dolgoushin and Osipova (1973) on Medvezhy Glacier; Bindschadler and others (1977), Kamb and others (1985), and Raymond and Harrison (1986, in press) on Variegated Glacier, and Clarke and others (1984) on the pre-surge phase of Trapridge Glacier, have each led to separate theoretical ideas on how and when surges are initiated, the dynamics of their propagation, and the reason for termination.…”

Section: Introductionmentioning

confidence: 99%

Some Observations on a Recent Surge of Peters Glacier, Alaska, U.S.A.

Echelmeyer

Butterfield²,

Cuillard³

1987

J. Glaciol.

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A spectacular surge occurred on Peters Glacier, Alaska, in 1986 and 1987. Several observations on the glacier were made during the course of its surge. These observations are compared with those on other surging glaciers and then interpreted in terms of the ideas on surge mechanisms and dynamics as originally postulated by Post (unpublished) and further developed during the surge of Variegated Glacier by Kamb and others (1985) and Raymond and Harrison (1986, in press). It is shown that the concepts of rapid basal motion due to high water pressure at the glacier bed and the initiation of a surge during the winter due to a pressurization of the limited supply of basal water are well supported by these observations on the surge of Peters Glacier. An extremely high suspended sediment load rich in very fine material was observed, which also supports ideas on basal processes expected during this type of surge.One interesting (and puzzling) feature of this surge cycle is that the termination of the surge occurred in late winter 1987, when surface melt water was at a minimum. This is in direct contrast to the termination of the surge on Variegated Glacier, which occurred during the period of peak ablation.

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Flow, thermal structure, and subglacial conditions of a surge-type glacier

Cited by 277 publications

References 28 publications

Surge dynamics in the Nathorstbreen glacier system, Svalbard

Surge dynamics in the Nathorstbreen glacier system, Svalbard

Drainage-Basin Characteristics of Nordaustlandet Ice Caps, Svalbard

Some Observations on a Recent Surge of Peters Glacier, Alaska, U.S.A.

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