A surge of the glaciers Skobreen–Paulabreen, Svalbard, observed by time-lapse photographs and remote sensing data

Kristensen, Lene; Benn, Douglas I.

doi:10.3402/polar.v31i0.11106

Cited by 31 publications

(44 citation statements)

References 35 publications

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“…Apron entrainment is likely to have been responsible for the formation of the solid subfacies (at the NW section), interpreted as locally derived supraglacial or paraglacial material that has been entrained into the subglacial till, before both have been stacked, by folding and faulting, up over banded subfacies ice at~30-45 m (as) (Figures 2a and 6d). These processes are consistent with observations from Paulabreen, which shows continuous failure and dry calving of ice across the entire terrestrial margin, as well as the deformation and overriding of debris-rich stagnant ice and ice marginal sediments [Kristensen and Benn, 2012].…”

Section: Apron Entrainmentsupporting

confidence: 90%

“…The solid stratified facies has also been thrust up The basal stratigraphy at the NW section is interpreted to be the result of active surging ice encountering inactive ice and the bed of the glacier in a terrestrial position at the side of the fjord, resulting in units being sheared over each other and stacked. Observations of such processes can be seen within the time-lapse imagery of the 2005 Paulabreen surge [Kristensen and Benn, 2012], which shows the movement of ice blocks over each other and the incorporation of debris-rich inactive ice at the terrestrial margin.…”

Section: Thickening and Stacking Of Basal Ice Faciesmentioning

confidence: 99%

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Debris entrainment and landform genesis during tidewater glacier surges

et al. 2015

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The englacial entrainment of basal debris during surges presents an opportunity to investigate processes acting at the glacier bed. The subsequent melt-out of debris-rich englacial structures during the quiescent phase produces geometrical ridge networks on glacier forelands that are diagnostic of surge activity. We investigate the link between debris entrainment and proglacial geomorphology by analyzing basal ice, englacial structures, and ridge networks exposed at the margins of Tunabreen, a tidewater surge-type glacier in Svalbard. The basal ice facies display clear evidence for brittle and ductile tectonic deformation, resulting in overall thickening of the basal ice sequence. The formation of debris-poor dispersed facies ice is the result of strain-induced metamorphism of meteoric ice near the bed. Debris-rich englacial structures display a variety of characteristics and morphologies and are interpreted to represent the incorporation and elevation of subglacial till via the squeezing of till into basal crevasses and hydrofracture exploitation of thrust faults, reoriented crevasse squeezes, and preexisting fractures. These structures are observed to melt-out and form embryonic geometrical ridge networks at the base of a terrestrially grounded ice cliff. Ridge networks are also located at the terrestrial margins of Tunabreen, neighboring Von Postbreen, and in a submarine position within Tempelfjorden. Analysis of network characteristics allows these ridges to be linked to different formational mechanisms of their parent debris-rich englacial structures. This in turn provides an insight into variations in the dominant tectonic stress regimes acting across the glacier during surges.

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Section: Apron Entrainmentsupporting

confidence: 90%

Section: Thickening and Stacking Of Basal Ice Faciesmentioning

confidence: 99%

Debris entrainment and landform genesis during tidewater glacier surges

et al. 2015

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“…Basal crevasses in turn have been proposed to form during surge stagnation, in a zone of longitudinal extension or intense compression, when basal water pressures are close to ice overburden pressures and allow for the propagation of basal crevasses (Larsen et al . ; Kristensen & Benn ; Lovell et al . ).…”

Section: Submarine Landforms In Mohnbuktamentioning

confidence: 99%

Holocene glacial evolution of Mohnbukta in eastern Spitsbergen

Flink¹,

Hill²,

Noormets³

et al. 2017

Boreas

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Submarine geomorphology is one of the main tools for understanding past fluctuations of tidewater glaciers. In this study we investigate the glacial history of Mohnbukta, on the east coast of Spitsbergen, Svalbard, by combining multibeam‐bathymetric data, marine sediment cores and remote sensing data. Presently, three tidewater glaciers, Heuglinbreen, Königsbergbreen and Hayesbreen calve into Mohnbukta. Hayesbreen surged at the end of the Little Ice Age, between 1901 and 1910. The submarine landform assemblage in Mohnbukta contains two large transverse ridges, interpreted as terminal moraines, with debrisflow lobes on their distal slopes and sets of well‐preserved geometric networks of ridges, interpreted as crevasse‐squeeze ridges inshore of the moraines. The arrangement of crevasse‐squeeze ridges suggests that both landform sets were produced during surge‐type advances. The terminus position of the 1901–1910 Hayesbreen surge correlates with the inner (R.2) terminal moraine ridge suggesting that the R.1 ridge formed prior to 1901. Marine sediment cores display 14C ages between 5700–7700 cal. a BP derived from benthic foraminifera, from a clast‐rich mud unit. This unit represents pre‐surge unconsolidated Holocene sediments pushed in front of the glacier terminus and mixed up during the 1901 surge. An absence of retreat moraines in the deeper part of the inner basin and the observation of tabular icebergs calving off the glacier front during retreat suggest that the front of Hayesbreen was close to flotation, at least in the deeper parts of the basin. As the MOH15‐01 core does not penetrate into a subglacial till and the foraminifera in the samples were well preserved, the R.1 ridge is suggested to have formed prior to the deposition of the foraminifera. Based on these data we propose that a surge‐type advance occurred in Mohnbukta in the early Holocene, prior to 7700 cal. a BP, which in turn indicates that glaciers can switch to and from surge mode.

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“…Quantitative studies of Svalbard glaciers, however, have concentrated mainly on transformations in glacier geometry, dynamics and mass balance (e.g. Hagen and Liestøl, 1990;Hagen et al, 1993;Jania and Hagen, 1996;Melvold and Hagen, 1998;Ziaja, 2001;Bamber et al, 2005;Ziaja, 2005;Nuth et al, 2007;Zagorski et al, 2008Zagorski et al, , 2012Sund et al, 2009;Moholdt et al, 2010a,b;Nuth et al, 2010;Kristensen and Benn, 2012;Mansell et al, 2012;Murray et al, 2012;Błaszczyk et al, 2013;Małecki, 2013). Quantification of changes in glacial landforms, including transformations due to dead-ice melting, has been made in a much smaller number of studies (e.g.…”

Section: Introductionmentioning

confidence: 99%

Quantification of the ice-cored moraines' short-term dynamics in the high-Arctic glaciers Ebbabreen and Ragnarbreen, Petuniabukta, Svalbard

Ewertowski

Tomczyk

2015

Geomorphology

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Extensive ice-cored moraine complexes are common elements, marking the last advance of many Svalbard glaciers. Sediment gravity flows are among the most dynamic processes, transforming these landforms. The short-term (yearly and weekly) dynamics of mass-wasting processes were studied in a cm-scale using repetitive topographic scanning. We monitored several active sites on the forelands of two glaciers, Ebbabreen and Ragnarbreen, both of which are located near the Petuniabukta at the northern end of Billefjorden in Spitsbergen.The surveys indicate high dynamic rates of landforms' transformation. The mean annual volume loss of sediments and dead-ice for the most active parts of the moraines was up to 1.8 m a -1 . However, most of the transformation occurred during summer, with the short-term values of mean elevation changes as high as −104 mm day −1 . In comparison, the dynamics of the other (i.e. non-active) parts of the ice-cored moraines were much lower, namely, the mean annual lowering (attributed mainly to dead-ice downwasting) was up to 0.3 m a -1 , whereas lowering during summer was up to 8 mm day −1 . Our results indicate that in the case of the studied glaciers, backwasting was much more effective than downwasting in terms of landscape transformation in the glacier forelands. However, despite the high activity of localised mass movement processes, the overall short-term dynamics of ice-cored moraines for the studied glaciers were relatively low. We suggest that as long as debris cover is sufficiently thick (thicker than the permafrost's active layer depths), the mass movement activity would occur only under specific topographic conditions and/or due to occurrence of external meltwater sources and slope undercutting. In other areas, ice-cored moraines remain a stable landsystem component in a yearly to decadal time-scale. Graphical abstractPlease cite this article as: Ewertowski, Marek W., Tomczyk, Aleksandra M., Quantification of the ice-cored moraines' short-term dynamics in the high-Arctic glaciers Ebbabreen and Ragnarbreen, Petuniabukta, Svalbard, Geomorphology 234 (2015): 211-227,

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A surge of the glaciers Skobreen–Paulabreen, Svalbard, observed by time-lapse photographs and remote sensing data

Cited by 31 publications

References 35 publications

Debris entrainment and landform genesis during tidewater glacier surges

Debris entrainment and landform genesis during tidewater glacier surges

Holocene glacial evolution of Mohnbukta in eastern Spitsbergen

Quantification of the ice-cored moraines' short-term dynamics in the high-Arctic glaciers Ebbabreen and Ragnarbreen, Petuniabukta, Svalbard

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