Debris entrainment and landform genesis during tidewater glacier surges

Harold Lovell* (Corresponding Author), Edward J. Fleming, Douglas I. Benn, Bryn Hubbard, Sven Lukas, Brice R. Rea, Riko Noormets, Anne E. Flink

*Corresponding author for this work

Research output: Contribution to journalArticle

20 Citations (Scopus)
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Abstract

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.

Original languageEnglish
Pages (from-to)1574-1595
Number of pages22
JournalJournal of Geophysical Research: Earth Surface
Volume120
Issue number8
Early online date22 Aug 2015
DOIs
Publication statusPublished - Aug 2015

Fingerprint

glacier surge
tidewater glacier
basal ice
Landforms
landforms
Glaciers
glaciers
Ice
entrainment
debris
Debris
landform
crevasse
glacier
ice
ridges
crevasses
melt
tectonics
Tectonics

Keywords

  • basal ice
  • debris-rich structures
  • geometrical ridge networks
  • glacier surge
  • Svalbard

ASJC Scopus subject areas

  • Earth-Surface Processes
  • Geophysics

Cite this

Lovell, H., Fleming, E. J., Benn, D. I., Hubbard, B., Lukas, S., Rea, B. R., ... Flink, A. E. (2015). Debris entrainment and landform genesis during tidewater glacier surges. Journal of Geophysical Research: Earth Surface, 120(8), 1574-1595. https://doi.org/10.1002/2015JF003509

Debris entrainment and landform genesis during tidewater glacier surges. / Lovell, Harold (Corresponding Author); Fleming, Edward J.; Benn, Douglas I.; Hubbard, Bryn; Lukas, Sven; Rea, Brice R.; Noormets, Riko; Flink, Anne E.

In: Journal of Geophysical Research: Earth Surface, Vol. 120, No. 8, 08.2015, p. 1574-1595.

Research output: Contribution to journalArticle

Lovell, H, Fleming, EJ, Benn, DI, Hubbard, B, Lukas, S, Rea, BR, Noormets, R & Flink, AE 2015, 'Debris entrainment and landform genesis during tidewater glacier surges', Journal of Geophysical Research: Earth Surface, vol. 120, no. 8, pp. 1574-1595. https://doi.org/10.1002/2015JF003509
Lovell, Harold ; Fleming, Edward J. ; Benn, Douglas I. ; Hubbard, Bryn ; Lukas, Sven ; Rea, Brice R. ; Noormets, Riko ; Flink, Anne E. / Debris entrainment and landform genesis during tidewater glacier surges. In: Journal of Geophysical Research: Earth Surface. 2015 ; Vol. 120, No. 8. pp. 1574-1595.
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abstract = "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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