Ice-sheet grounding-zone wedges (GZWs) on high-latitude continental margins
© 2015 Elsevier B.V. Grounding-zone wedges (GZWs) are asymmetric sedimentary depocentres which form through the rapid accumulation of glacigenic debris along a line-source at the grounding zone of marine-terminating ice sheets during still-stands in ice-sheet retreat. GZWs form largely through the d...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/247712 2024-02-04T09:55:50+01:00 Ice-sheet grounding-zone wedges (GZWs) on high-latitude continental margins Batchelor, CL Dowdeswell, JA 2015-05-01 application/pdf https://www.repository.cam.ac.uk/handle/1810/247712 eng eng Elsevier BV http://dx.doi.org/10.1016/j.margeo.2015.02.001 Marine Geology https://www.repository.cam.ac.uk/handle/1810/247712 Attribution-NonCommercial-NoDerivs 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-nd/2.0/uk/ Grounding-zone wedges Palaeo-ice streams Cross-shelf troughs Seismic reflection Pinning points Ice shelves Article 2015 ftunivcam 2024-01-11T23:28:13Z © 2015 Elsevier B.V. Grounding-zone wedges (GZWs) are asymmetric sedimentary depocentres which form through the rapid accumulation of glacigenic debris along a line-source at the grounding zone of marine-terminating ice sheets during still-stands in ice-sheet retreat. GZWs form largely through the delivery of deforming subglacial sediments. The presence of GZWs in the geological record indicates an episodic style of ice retreat punctuated by still-stands in grounding-zone position. Moraine ridges and ice-proximal fans may also build up at the grounding zone during still-stands of the ice margin, but these require either considerable vertical accommodation space or sediment derived from point-sourced subglacial meltwater streams. By contrast, GZWs form mainly where floating ice shelves constrain vertical accommodation space immediately beyond the grounding-zone. An inventory of GZWs is compiled from available studies of bathymetric and acoustic data from high-latitude continental margins. The locations and dimensions of GZWs from the Arctic and Antarctic, alongside a synthesis of their key architectural and geomorphic characteristics, are presented. GZWs are only observed within cross-shelf troughs and major fjord systems, which are the former locations of ice streams and fast-flowing outlet glaciers. Typical high-latitude GZWs are less than 15. km in along-flow direction and 15 to 100. m thick. GZWs possess a transparent to chaotic acoustic character, which reflects the delivery of diamictic subglacial debris. Many GZWs contain seaward-dipping reflections, which indicate sediment progradation and wedge-growth through continued delivery of basal sediments. GZW formation is inferred to require high rates of sediment delivery to a fast-flowing ice margin that is relatively stable for probably decades to centuries. Although the long-term stability of the grounding zone is controlled by ice-sheet mass balance, the precise location of any still-stands is influenced strongly by the geometry of the continental shelf. ... Article in Journal/Newspaper Antarc* Antarctic Arctic Ice Sheet Ice Shelves Apollo - University of Cambridge Repository Arctic Antarctic |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
Grounding-zone wedges Palaeo-ice streams Cross-shelf troughs Seismic reflection Pinning points Ice shelves |
spellingShingle |
Grounding-zone wedges Palaeo-ice streams Cross-shelf troughs Seismic reflection Pinning points Ice shelves Batchelor, CL Dowdeswell, JA Ice-sheet grounding-zone wedges (GZWs) on high-latitude continental margins |
topic_facet |
Grounding-zone wedges Palaeo-ice streams Cross-shelf troughs Seismic reflection Pinning points Ice shelves |
description |
© 2015 Elsevier B.V. Grounding-zone wedges (GZWs) are asymmetric sedimentary depocentres which form through the rapid accumulation of glacigenic debris along a line-source at the grounding zone of marine-terminating ice sheets during still-stands in ice-sheet retreat. GZWs form largely through the delivery of deforming subglacial sediments. The presence of GZWs in the geological record indicates an episodic style of ice retreat punctuated by still-stands in grounding-zone position. Moraine ridges and ice-proximal fans may also build up at the grounding zone during still-stands of the ice margin, but these require either considerable vertical accommodation space or sediment derived from point-sourced subglacial meltwater streams. By contrast, GZWs form mainly where floating ice shelves constrain vertical accommodation space immediately beyond the grounding-zone. An inventory of GZWs is compiled from available studies of bathymetric and acoustic data from high-latitude continental margins. The locations and dimensions of GZWs from the Arctic and Antarctic, alongside a synthesis of their key architectural and geomorphic characteristics, are presented. GZWs are only observed within cross-shelf troughs and major fjord systems, which are the former locations of ice streams and fast-flowing outlet glaciers. Typical high-latitude GZWs are less than 15. km in along-flow direction and 15 to 100. m thick. GZWs possess a transparent to chaotic acoustic character, which reflects the delivery of diamictic subglacial debris. Many GZWs contain seaward-dipping reflections, which indicate sediment progradation and wedge-growth through continued delivery of basal sediments. GZW formation is inferred to require high rates of sediment delivery to a fast-flowing ice margin that is relatively stable for probably decades to centuries. Although the long-term stability of the grounding zone is controlled by ice-sheet mass balance, the precise location of any still-stands is influenced strongly by the geometry of the continental shelf. ... |
format |
Article in Journal/Newspaper |
author |
Batchelor, CL Dowdeswell, JA |
author_facet |
Batchelor, CL Dowdeswell, JA |
author_sort |
Batchelor, CL |
title |
Ice-sheet grounding-zone wedges (GZWs) on high-latitude continental margins |
title_short |
Ice-sheet grounding-zone wedges (GZWs) on high-latitude continental margins |
title_full |
Ice-sheet grounding-zone wedges (GZWs) on high-latitude continental margins |
title_fullStr |
Ice-sheet grounding-zone wedges (GZWs) on high-latitude continental margins |
title_full_unstemmed |
Ice-sheet grounding-zone wedges (GZWs) on high-latitude continental margins |
title_sort |
ice-sheet grounding-zone wedges (gzws) on high-latitude continental margins |
publisher |
Elsevier BV |
publishDate |
2015 |
url |
https://www.repository.cam.ac.uk/handle/1810/247712 |
geographic |
Arctic Antarctic |
geographic_facet |
Arctic Antarctic |
genre |
Antarc* Antarctic Arctic Ice Sheet Ice Shelves |
genre_facet |
Antarc* Antarctic Arctic Ice Sheet Ice Shelves |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/247712 |
op_rights |
Attribution-NonCommercial-NoDerivs 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-nd/2.0/uk/ |
_version_ |
1789960004692869120 |