Geomorphological investigation of multiphase glacitectonic composite ridge systems in Svalbard

Harold Lovell, Douglas I. Benn, Sven Lukas, Matteo Spagnolo, Simon Cook, Darrel A. Swift, Chris D. Clark, Jacob C. Yde, Tom P. Watts

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Abstract

Some surge-type glaciers on the High-Arctic archipelago of Svalbard have large glacitectonic composite ridge systems at their terrestrial margins. These have formed by rapid glacier advance into proglacial sediments during the active surge phase, creating multicrested moraine complexes. Such complexes can be formed during single surge advances or multiple surges to successively less-extensive positions. The few existing studies of composite ridge systems have relied on detailed information on internal structure and sedimentology to reconstruct their formation and links to surge processes. However, natural exposures of internal structure are commonly unavailable, and the creation of artificial exposures is often problematic in fragile Arctic environments. To compensate for these issues, we investigate the potential for reconstructing composite ridge system formation based on geomorphological evidence alone, focusing on clear morphostratigraphic relationships between ridges within the moraine complex and relict meltwater channels/outwash fans. Based on mapping at the margins of Finsterwalderbreen (in Van Keulenfjorden) and Grønfjordbreen (in Grønfjorden), we show that relict meltwater channels that breach outer parts of the composite ridge systems are in most cases truncated upstream within the ridge complex by an inner pushed ridge or ridges at their ice-proximal extents. Our interpretation of this relationship is that the entire composite ridge system is unlikely to have formed during the same glacier advance but is instead the product of multiple advances to successively less-extensive positions, whereby younger ridges are emplaced on the ice-proximal side of older ridges. This indicates that the Finsterwalderbreen composite ridge system has been formed by multiple separate advances, consistent with the cyclicity of surges. Being able to identify the frequency and magnitude of former surges is important as it provides insight into the past behaviour of surge-type glaciers and, if absolute dating is possible, allows for the assessment of surge-type glacier response to climate change on decadal to centennial timescales. Although further investigations into the internal structure of these deposits should be sought where possible, our study demonstrates that geomorphology could be an invaluable tool for reconstructing the formation of composite ridge systems
Original languageEnglish
Pages (from-to)176-188
Number of pages13
JournalGeomorphology
Volume300
Early online date31 Oct 2017
DOIs
Publication statusPublished - 1 Jan 2018

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glacier advance
glacier
moraine
meltwater
ice
arctic environment
outwash
cyclicity
sedimentology
geomorphology
archipelago
timescale
climate change
sediment
exposure
dating
product
young

Keywords

  • Glacial geomorphology
  • Glacier surge
  • Glacitectonic composite ridge system
  • Svalbard

Cite this

Lovell, Harold ; Benn, Douglas I. ; Lukas, Sven ; Spagnolo, Matteo ; Cook, Simon ; Swift, Darrel A. ; Clark, Chris D. ; Yde, Jacob C. ; Watts, Tom P. / Geomorphological investigation of multiphase glacitectonic composite ridge systems in Svalbard. In: Geomorphology. 2018 ; Vol. 300. pp. 176-188.
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abstract = "Some surge-type glaciers on the High-Arctic archipelago of Svalbard have large glacitectonic composite ridge systems at their terrestrial margins. These have formed by rapid glacier advance into proglacial sediments during the active surge phase, creating multicrested moraine complexes. Such complexes can be formed during single surge advances or multiple surges to successively less-extensive positions. The few existing studies of composite ridge systems have relied on detailed information on internal structure and sedimentology to reconstruct their formation and links to surge processes. However, natural exposures of internal structure are commonly unavailable, and the creation of artificial exposures is often problematic in fragile Arctic environments. To compensate for these issues, we investigate the potential for reconstructing composite ridge system formation based on geomorphological evidence alone, focusing on clear morphostratigraphic relationships between ridges within the moraine complex and relict meltwater channels/outwash fans. Based on mapping at the margins of Finsterwalderbreen (in Van Keulenfjorden) and Gr{\o}nfjordbreen (in Gr{\o}nfjorden), we show that relict meltwater channels that breach outer parts of the composite ridge systems are in most cases truncated upstream within the ridge complex by an inner pushed ridge or ridges at their ice-proximal extents. Our interpretation of this relationship is that the entire composite ridge system is unlikely to have formed during the same glacier advance but is instead the product of multiple advances to successively less-extensive positions, whereby younger ridges are emplaced on the ice-proximal side of older ridges. This indicates that the Finsterwalderbreen composite ridge system has been formed by multiple separate advances, consistent with the cyclicity of surges. Being able to identify the frequency and magnitude of former surges is important as it provides insight into the past behaviour of surge-type glaciers and, if absolute dating is possible, allows for the assessment of surge-type glacier response to climate change on decadal to centennial timescales. Although further investigations into the internal structure of these deposits should be sought where possible, our study demonstrates that geomorphology could be an invaluable tool for reconstructing the formation of composite ridge systems",
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Lovell, H, Benn, DI, Lukas, S, Spagnolo, M, Cook, S, Swift, DA, Clark, CD, Yde, JC & Watts, TP 2018, 'Geomorphological investigation of multiphase glacitectonic composite ridge systems in Svalbard', Geomorphology, vol. 300, pp. 176-188. https://doi.org/10.1016/j.geomorph.2017.10.024

Geomorphological investigation of multiphase glacitectonic composite ridge systems in Svalbard. / Lovell, Harold; Benn, Douglas I.; Lukas, Sven; Spagnolo, Matteo; Cook, Simon; Swift, Darrel A.; Clark, Chris D.; Yde, Jacob C.; Watts, Tom P.

In: Geomorphology, Vol. 300, 01.01.2018, p. 176-188.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Geomorphological investigation of multiphase glacitectonic composite ridge systems in Svalbard

AU - Lovell, Harold

AU - Benn, Douglas I.

AU - Lukas, Sven

AU - Spagnolo, Matteo

AU - Cook, Simon

AU - Swift, Darrel A.

AU - Clark, Chris D.

AU - Yde, Jacob C.

AU - Watts, Tom P.

N1 - © 2017 Elsevier B.V. All rights reserved.

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Some surge-type glaciers on the High-Arctic archipelago of Svalbard have large glacitectonic composite ridge systems at their terrestrial margins. These have formed by rapid glacier advance into proglacial sediments during the active surge phase, creating multicrested moraine complexes. Such complexes can be formed during single surge advances or multiple surges to successively less-extensive positions. The few existing studies of composite ridge systems have relied on detailed information on internal structure and sedimentology to reconstruct their formation and links to surge processes. However, natural exposures of internal structure are commonly unavailable, and the creation of artificial exposures is often problematic in fragile Arctic environments. To compensate for these issues, we investigate the potential for reconstructing composite ridge system formation based on geomorphological evidence alone, focusing on clear morphostratigraphic relationships between ridges within the moraine complex and relict meltwater channels/outwash fans. Based on mapping at the margins of Finsterwalderbreen (in Van Keulenfjorden) and Grønfjordbreen (in Grønfjorden), we show that relict meltwater channels that breach outer parts of the composite ridge systems are in most cases truncated upstream within the ridge complex by an inner pushed ridge or ridges at their ice-proximal extents. Our interpretation of this relationship is that the entire composite ridge system is unlikely to have formed during the same glacier advance but is instead the product of multiple advances to successively less-extensive positions, whereby younger ridges are emplaced on the ice-proximal side of older ridges. This indicates that the Finsterwalderbreen composite ridge system has been formed by multiple separate advances, consistent with the cyclicity of surges. Being able to identify the frequency and magnitude of former surges is important as it provides insight into the past behaviour of surge-type glaciers and, if absolute dating is possible, allows for the assessment of surge-type glacier response to climate change on decadal to centennial timescales. Although further investigations into the internal structure of these deposits should be sought where possible, our study demonstrates that geomorphology could be an invaluable tool for reconstructing the formation of composite ridge systems

AB - Some surge-type glaciers on the High-Arctic archipelago of Svalbard have large glacitectonic composite ridge systems at their terrestrial margins. These have formed by rapid glacier advance into proglacial sediments during the active surge phase, creating multicrested moraine complexes. Such complexes can be formed during single surge advances or multiple surges to successively less-extensive positions. The few existing studies of composite ridge systems have relied on detailed information on internal structure and sedimentology to reconstruct their formation and links to surge processes. However, natural exposures of internal structure are commonly unavailable, and the creation of artificial exposures is often problematic in fragile Arctic environments. To compensate for these issues, we investigate the potential for reconstructing composite ridge system formation based on geomorphological evidence alone, focusing on clear morphostratigraphic relationships between ridges within the moraine complex and relict meltwater channels/outwash fans. Based on mapping at the margins of Finsterwalderbreen (in Van Keulenfjorden) and Grønfjordbreen (in Grønfjorden), we show that relict meltwater channels that breach outer parts of the composite ridge systems are in most cases truncated upstream within the ridge complex by an inner pushed ridge or ridges at their ice-proximal extents. Our interpretation of this relationship is that the entire composite ridge system is unlikely to have formed during the same glacier advance but is instead the product of multiple advances to successively less-extensive positions, whereby younger ridges are emplaced on the ice-proximal side of older ridges. This indicates that the Finsterwalderbreen composite ridge system has been formed by multiple separate advances, consistent with the cyclicity of surges. Being able to identify the frequency and magnitude of former surges is important as it provides insight into the past behaviour of surge-type glaciers and, if absolute dating is possible, allows for the assessment of surge-type glacier response to climate change on decadal to centennial timescales. Although further investigations into the internal structure of these deposits should be sought where possible, our study demonstrates that geomorphology could be an invaluable tool for reconstructing the formation of composite ridge systems

KW - Glacial geomorphology

KW - Glacier surge

KW - Glacitectonic composite ridge system

KW - Svalbard

U2 - 10.1016/j.geomorph.2017.10.024

DO - 10.1016/j.geomorph.2017.10.024

M3 - Article

VL - 300

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EP - 188

JO - Geomorphology

JF - Geomorphology

SN - 0169-555X

ER -