A comprehensive interpretation of the NEEM basal ice build-up using a multi-parametric approach
Basal ice is a common expression to describe bottom ice layers of glaciers, ice caps and ice sheets in which the ice is primarily conditioned by processes operating at the bed. It is chemically and/or physically distinct from the ice above and can be characterized by a component of basally derived s...
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Format: | Article in Journal/Newspaper |
Language: | English |
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Copernicus Publications
2016
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Online Access: | https://doi.org/10.5194/tc-10-553-2016 http://www.the-cryosphere.net/10/553/2016/tc-10-553-2016.pdf https://doaj.org/article/eeea22ec801748c19fce801ddf0d295e |
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fttriple:oai:gotriple.eu:oai:doaj.org/article:eeea22ec801748c19fce801ddf0d295e 2023-05-15T16:28:56+02:00 A comprehensive interpretation of the NEEM basal ice build-up using a multi-parametric approach T. Goossens C. J. Sapart D. Dahl-Jensen T. Popp S. El Amri J.-L. Tison 2016-03-01 https://doi.org/10.5194/tc-10-553-2016 http://www.the-cryosphere.net/10/553/2016/tc-10-553-2016.pdf https://doaj.org/article/eeea22ec801748c19fce801ddf0d295e en eng Copernicus Publications 1994-0416 1994-0424 doi:10.5194/tc-10-553-2016 http://www.the-cryosphere.net/10/553/2016/tc-10-553-2016.pdf https://doaj.org/article/eeea22ec801748c19fce801ddf0d295e undefined The Cryosphere, Vol 10, Iss 2, Pp 553-567 (2016) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2016 fttriple https://doi.org/10.5194/tc-10-553-2016 2023-01-22T19:15:57Z Basal ice is a common expression to describe bottom ice layers of glaciers, ice caps and ice sheets in which the ice is primarily conditioned by processes operating at the bed. It is chemically and/or physically distinct from the ice above and can be characterized by a component of basally derived sediments. The study of basal ice properties provides a rare opportunity to improve our understanding of subglacial environments and processes and to refine ice sheet behaviour modelling. Here, we present and discuss the results of water stable isotopes (δ18O and δD), ice fabrics, debris weight/size distribution and gas content of the basal part of the NEEM (North Greenland Eemian Ice Drilling Project) ice core. Below a depth of 2533.85 m, almost 10 m of basal debris-rich material was retrieved from the borehole, and regular occurrence of frozen sediments with only interstitial ice lenses in the bottom 5 m suggest that the ice–bedrock interface was reached. The sequence is composed of an alternation of three visually contrasting types of ice: clear ice with specks (very small amounts) of particulate inclusions, stratified debris-rich layers and ice containing dispersed debris. The use of water stable isotope signatures (δ18O and δD), together with other parameters, allows discrimination between the different types of ice and to unravel the processes involved in their formation and transformation. The basal debris-rich material presents δ18O values [−39.9 ‰; −34.4 ‰] within the range of the above last 300 m of unaltered meteoric ice [−44.9 ‰; −30.6 ‰] spanning a glacial-interglacial range of values. This rules out the hypothesis of a basal ice layer originating from pre-ice sheet ice overridden by the growing ice sheet, as previously suggested e.g. in the case of GRIP (Greenland Ice Core Project). We show that clear basal ice with specks corresponds to altered meteoric glacial ice where some of the climatic signal could have been preserved. However, the stratified debris-rich layers and the ice containing dispersed ... Article in Journal/Newspaper Greenland Greenland ice core Greenland Ice core Project GRIP ice core Ice Sheet North Greenland The Cryosphere Unknown Greenland The Cryosphere 10 2 553 567 |
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Open Polar |
collection |
Unknown |
op_collection_id |
fttriple |
language |
English |
topic |
geo envir |
spellingShingle |
geo envir T. Goossens C. J. Sapart D. Dahl-Jensen T. Popp S. El Amri J.-L. Tison A comprehensive interpretation of the NEEM basal ice build-up using a multi-parametric approach |
topic_facet |
geo envir |
description |
Basal ice is a common expression to describe bottom ice layers of glaciers, ice caps and ice sheets in which the ice is primarily conditioned by processes operating at the bed. It is chemically and/or physically distinct from the ice above and can be characterized by a component of basally derived sediments. The study of basal ice properties provides a rare opportunity to improve our understanding of subglacial environments and processes and to refine ice sheet behaviour modelling. Here, we present and discuss the results of water stable isotopes (δ18O and δD), ice fabrics, debris weight/size distribution and gas content of the basal part of the NEEM (North Greenland Eemian Ice Drilling Project) ice core. Below a depth of 2533.85 m, almost 10 m of basal debris-rich material was retrieved from the borehole, and regular occurrence of frozen sediments with only interstitial ice lenses in the bottom 5 m suggest that the ice–bedrock interface was reached. The sequence is composed of an alternation of three visually contrasting types of ice: clear ice with specks (very small amounts) of particulate inclusions, stratified debris-rich layers and ice containing dispersed debris. The use of water stable isotope signatures (δ18O and δD), together with other parameters, allows discrimination between the different types of ice and to unravel the processes involved in their formation and transformation. The basal debris-rich material presents δ18O values [−39.9 ‰; −34.4 ‰] within the range of the above last 300 m of unaltered meteoric ice [−44.9 ‰; −30.6 ‰] spanning a glacial-interglacial range of values. This rules out the hypothesis of a basal ice layer originating from pre-ice sheet ice overridden by the growing ice sheet, as previously suggested e.g. in the case of GRIP (Greenland Ice Core Project). We show that clear basal ice with specks corresponds to altered meteoric glacial ice where some of the climatic signal could have been preserved. However, the stratified debris-rich layers and the ice containing dispersed ... |
format |
Article in Journal/Newspaper |
author |
T. Goossens C. J. Sapart D. Dahl-Jensen T. Popp S. El Amri J.-L. Tison |
author_facet |
T. Goossens C. J. Sapart D. Dahl-Jensen T. Popp S. El Amri J.-L. Tison |
author_sort |
T. Goossens |
title |
A comprehensive interpretation of the NEEM basal ice build-up using a multi-parametric approach |
title_short |
A comprehensive interpretation of the NEEM basal ice build-up using a multi-parametric approach |
title_full |
A comprehensive interpretation of the NEEM basal ice build-up using a multi-parametric approach |
title_fullStr |
A comprehensive interpretation of the NEEM basal ice build-up using a multi-parametric approach |
title_full_unstemmed |
A comprehensive interpretation of the NEEM basal ice build-up using a multi-parametric approach |
title_sort |
comprehensive interpretation of the neem basal ice build-up using a multi-parametric approach |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/tc-10-553-2016 http://www.the-cryosphere.net/10/553/2016/tc-10-553-2016.pdf https://doaj.org/article/eeea22ec801748c19fce801ddf0d295e |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Greenland ice core Greenland Ice core Project GRIP ice core Ice Sheet North Greenland The Cryosphere |
genre_facet |
Greenland Greenland ice core Greenland Ice core Project GRIP ice core Ice Sheet North Greenland The Cryosphere |
op_source |
The Cryosphere, Vol 10, Iss 2, Pp 553-567 (2016) |
op_relation |
1994-0416 1994-0424 doi:10.5194/tc-10-553-2016 http://www.the-cryosphere.net/10/553/2016/tc-10-553-2016.pdf https://doaj.org/article/eeea22ec801748c19fce801ddf0d295e |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-10-553-2016 |
container_title |
The Cryosphere |
container_volume |
10 |
container_issue |
2 |
container_start_page |
553 |
op_container_end_page |
567 |
_version_ |
1766018626604761088 |