Former dynamic behaviour of a cold-based valley glacier on Svalbard revealed by basal ice and structural glaciology investigations
H.L. was funded by a UK Natural Environment Research Council (NERC) PhD studentship (NE/I528050/1), the Queen Mary Postgraduate Research Fund, and an Arctic Field Grant from the Research Council of Norway. E.J.F. was funded by a NERC PhD studentship as part of the GAINS (Glacial Activity in Neoprote...
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Online Access: | http://hdl.handle.net/10023/7724 https://doi.org/10.3189/2015JoG14J120 |
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ftstandrewserep:oai:research-repository.st-andrews.ac.uk:10023/7724 2023-07-02T03:31:24+02:00 Former dynamic behaviour of a cold-based valley glacier on Svalbard revealed by basal ice and structural glaciology investigations Lovell, H. Fleming, E.J. Benn, D.I. Hubbard, B. Lukas, S. Naegeli, K. University of St Andrews. Geography & Sustainable Development University of St Andrews. Bell-Edwards Geographic Data Institute 2015-11-01 20 application/pdf http://hdl.handle.net/10023/7724 https://doi.org/10.3189/2015JoG14J120 eng eng Journal of Glaciology Lovell , H , Fleming , E J , Benn , D I , Hubbard , B , Lukas , S & Naegeli , K 2015 , ' Former dynamic behaviour of a cold-based valley glacier on Svalbard revealed by basal ice and structural glaciology investigations ' , Journal of Glaciology , vol. 61 , no. 226 , pp. 309-328 . https://doi.org/10.3189/2015JoG14J120 0022-1430 PURE: 209403672 PURE UUID: 4de31780-5439-4c88-9d39-f0a15bf8c420 Scopus: 84937881421 WOS: 000355778000011 ORCID: /0000-0002-3604-0886/work/64697376 http://hdl.handle.net/10023/7724 https://doi.org/10.3189/2015JoG14J120 Copyright 2015 International Glaciological Society. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at http://dx.doi.org/10.3189/2015JoG14J120 Arctic glaciology Basal ice Ice dynamics Structural glaciology Subglacial sediments GB Physical geography NDAS GB Journal article 2015 ftstandrewserep https://doi.org/10.3189/2015JoG14J120 2023-06-13T18:26:20Z H.L. was funded by a UK Natural Environment Research Council (NERC) PhD studentship (NE/I528050/1), the Queen Mary Postgraduate Research Fund, and an Arctic Field Grant from the Research Council of Norway. E.J.F. was funded by a NERC PhD studentship as part of the GAINS (Glacial Activity in Neoproterozoic Svalbard) grant (NE/H004963/1). K.N. was funded by an Arctic Field Grant, the Swiss Society for Speleology, and the travel grant commission of the Swiss Academy of Science. Large numbers of small valley glaciers on Svalbard were thicker and more extensive during the Little Ice Age (LIA), demonstrated by prominent ice-cored moraines up to several kilometres beyond present-day margins. The majority of these glaciers have since experienced a long period of strongly negative mass balance during the 20th century and are now largely frozen to their beds, indicating they are likely to have undergone a thermal transition from a polythermal to a cold-based regime. We present evidence for such a switch by reconstructing the former flow dynamics and thermal regime of Tellbreen, a small cold-based valley glacier in central Spitsbergen, based on its basal sequence and glaciological structures. Within the basal sequence, the underlying matrix-supported diamict is interpreted as saturated subglacial traction till which has frozen at the bed, indicating that the thermal switch has resulted in a cessation of subglacial sediment deformation due to freezing of the former deforming layer. This is overlain by debris-poor dispersed facies ice, interpreted to have formed through strain-induced metamorphism of englacial ice. The sequential development of structures includes arcuate fracture traces, interpreted as shear planes formed in a compressive/transpressive stress regime; and fracture traces, interpreted as healed extensional crevasses. The formation of these sediment/ice facies and structures is indicative of dynamic, warm-based flow, most likely during the LIA when the glacier was significantly thicker. Publisher PDF ... Article in Journal/Newspaper Arctic glacier glacier Journal of Glaciology Svalbard Spitsbergen University of St Andrews: Digital Research Repository Arctic Norway Svalbard Tellbreen ENVELOPE(16.217,16.217,78.250,78.250) Journal of Glaciology 61 226 309 328 |
institution |
Open Polar |
collection |
University of St Andrews: Digital Research Repository |
op_collection_id |
ftstandrewserep |
language |
English |
topic |
Arctic glaciology Basal ice Ice dynamics Structural glaciology Subglacial sediments GB Physical geography NDAS GB |
spellingShingle |
Arctic glaciology Basal ice Ice dynamics Structural glaciology Subglacial sediments GB Physical geography NDAS GB Lovell, H. Fleming, E.J. Benn, D.I. Hubbard, B. Lukas, S. Naegeli, K. Former dynamic behaviour of a cold-based valley glacier on Svalbard revealed by basal ice and structural glaciology investigations |
topic_facet |
Arctic glaciology Basal ice Ice dynamics Structural glaciology Subglacial sediments GB Physical geography NDAS GB |
description |
H.L. was funded by a UK Natural Environment Research Council (NERC) PhD studentship (NE/I528050/1), the Queen Mary Postgraduate Research Fund, and an Arctic Field Grant from the Research Council of Norway. E.J.F. was funded by a NERC PhD studentship as part of the GAINS (Glacial Activity in Neoproterozoic Svalbard) grant (NE/H004963/1). K.N. was funded by an Arctic Field Grant, the Swiss Society for Speleology, and the travel grant commission of the Swiss Academy of Science. Large numbers of small valley glaciers on Svalbard were thicker and more extensive during the Little Ice Age (LIA), demonstrated by prominent ice-cored moraines up to several kilometres beyond present-day margins. The majority of these glaciers have since experienced a long period of strongly negative mass balance during the 20th century and are now largely frozen to their beds, indicating they are likely to have undergone a thermal transition from a polythermal to a cold-based regime. We present evidence for such a switch by reconstructing the former flow dynamics and thermal regime of Tellbreen, a small cold-based valley glacier in central Spitsbergen, based on its basal sequence and glaciological structures. Within the basal sequence, the underlying matrix-supported diamict is interpreted as saturated subglacial traction till which has frozen at the bed, indicating that the thermal switch has resulted in a cessation of subglacial sediment deformation due to freezing of the former deforming layer. This is overlain by debris-poor dispersed facies ice, interpreted to have formed through strain-induced metamorphism of englacial ice. The sequential development of structures includes arcuate fracture traces, interpreted as shear planes formed in a compressive/transpressive stress regime; and fracture traces, interpreted as healed extensional crevasses. The formation of these sediment/ice facies and structures is indicative of dynamic, warm-based flow, most likely during the LIA when the glacier was significantly thicker. Publisher PDF ... |
author2 |
University of St Andrews. Geography & Sustainable Development University of St Andrews. Bell-Edwards Geographic Data Institute |
format |
Article in Journal/Newspaper |
author |
Lovell, H. Fleming, E.J. Benn, D.I. Hubbard, B. Lukas, S. Naegeli, K. |
author_facet |
Lovell, H. Fleming, E.J. Benn, D.I. Hubbard, B. Lukas, S. Naegeli, K. |
author_sort |
Lovell, H. |
title |
Former dynamic behaviour of a cold-based valley glacier on Svalbard revealed by basal ice and structural glaciology investigations |
title_short |
Former dynamic behaviour of a cold-based valley glacier on Svalbard revealed by basal ice and structural glaciology investigations |
title_full |
Former dynamic behaviour of a cold-based valley glacier on Svalbard revealed by basal ice and structural glaciology investigations |
title_fullStr |
Former dynamic behaviour of a cold-based valley glacier on Svalbard revealed by basal ice and structural glaciology investigations |
title_full_unstemmed |
Former dynamic behaviour of a cold-based valley glacier on Svalbard revealed by basal ice and structural glaciology investigations |
title_sort |
former dynamic behaviour of a cold-based valley glacier on svalbard revealed by basal ice and structural glaciology investigations |
publishDate |
2015 |
url |
http://hdl.handle.net/10023/7724 https://doi.org/10.3189/2015JoG14J120 |
long_lat |
ENVELOPE(16.217,16.217,78.250,78.250) |
geographic |
Arctic Norway Svalbard Tellbreen |
geographic_facet |
Arctic Norway Svalbard Tellbreen |
genre |
Arctic glacier glacier Journal of Glaciology Svalbard Spitsbergen |
genre_facet |
Arctic glacier glacier Journal of Glaciology Svalbard Spitsbergen |
op_relation |
Journal of Glaciology Lovell , H , Fleming , E J , Benn , D I , Hubbard , B , Lukas , S & Naegeli , K 2015 , ' Former dynamic behaviour of a cold-based valley glacier on Svalbard revealed by basal ice and structural glaciology investigations ' , Journal of Glaciology , vol. 61 , no. 226 , pp. 309-328 . https://doi.org/10.3189/2015JoG14J120 0022-1430 PURE: 209403672 PURE UUID: 4de31780-5439-4c88-9d39-f0a15bf8c420 Scopus: 84937881421 WOS: 000355778000011 ORCID: /0000-0002-3604-0886/work/64697376 http://hdl.handle.net/10023/7724 https://doi.org/10.3189/2015JoG14J120 |
op_rights |
Copyright 2015 International Glaciological Society. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at http://dx.doi.org/10.3189/2015JoG14J120 |
op_doi |
https://doi.org/10.3189/2015JoG14J120 |
container_title |
Journal of Glaciology |
container_volume |
61 |
container_issue |
226 |
container_start_page |
309 |
op_container_end_page |
328 |
_version_ |
1770270801569775616 |