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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ftdoajarticles:oai:doaj.org/article:eeea22ec801748c19fce801ddf0d295e 2023-05-15T16:28:59+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 2016-03-01T00:00:00Z https://doi.org/10.5194/tc-10-553-2016 https://doaj.org/article/eeea22ec801748c19fce801ddf0d295e EN eng Copernicus Publications http://www.the-cryosphere.net/10/553/2016/tc-10-553-2016.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-10-553-2016 https://doaj.org/article/eeea22ec801748c19fce801ddf0d295e The Cryosphere, Vol 10, Iss 2, Pp 553-567 (2016) Environmental sciences GE1-350 Geology QE1-996.5 article 2016 ftdoajarticles https://doi.org/10.5194/tc-10-553-2016 2022-12-31T13:27:58Z 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 ( δ 18 O and δ D), 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 ( δ 18 O and δ D), 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 δ 18 O 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 ... Article in Journal/Newspaper Greenland Greenland ice core Greenland Ice core Project GRIP ice core Ice Sheet North Greenland The Cryosphere Directory of Open Access Journals: DOAJ Articles Greenland The Cryosphere 10 2 553 567 |
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Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 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 |
Environmental sciences GE1-350 Geology QE1-996.5 |
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 ( δ 18 O and δ D), 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 ( δ 18 O and δ D), 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 δ 18 O 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 ... |
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 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 |
http://www.the-cryosphere.net/10/553/2016/tc-10-553-2016.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-10-553-2016 https://doaj.org/article/eeea22ec801748c19fce801ddf0d295e |
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_ |
1766018679009443840 |