Differentiating bubble-free layers from melt layers in ice cores using noble gases
Melt layers are clear indicators of extreme summer warmth on polar ice caps. The visual identification of refrozen meltwater as clear bubble-free layers cannot be used to study some past warm periods, because, in deeper ice, bubbles are lost to clathrate formation. We present here a reliable method...
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ftcdlib:oai:escholarship.org:ark:/13030/qt0r15x7ww 2023-06-18T03:40:57+02:00 Differentiating bubble-free layers from melt layers in ice cores using noble gases Orsi, Anais J Kawamura, Kenji Fegyveresi, John M Headly, Melissa A Alley, Richard B Severinghaus, Jeffrey P 585 - 594 2015-01-01 application/pdf https://escholarship.org/uc/item/0r15x7ww unknown eScholarship, University of California qt0r15x7ww https://escholarship.org/uc/item/0r15x7ww public Journal of Glaciology, vol 61, iss 227 ice and climate ice core meltwater chemistry polar firn surface melt Physical Geography and Environmental Geoscience Meteorology & Atmospheric Sciences article 2015 ftcdlib 2023-06-05T18:01:52Z Melt layers are clear indicators of extreme summer warmth on polar ice caps. The visual identification of refrozen meltwater as clear bubble-free layers cannot be used to study some past warm periods, because, in deeper ice, bubbles are lost to clathrate formation. We present here a reliable method to detect melt events, based on the analysis of Kr/Ar and Xe/Ar ratios in ice cores, and apply it to the detection of melt in clathrate ice from the Eemian at NEEM, Greenland. Additionally, melt layers in ice cores can compromise the integrity of the gas record by dissolving soluble gases, or by altering gas transport in the firn, which affects the gas chronology. We find that the easily visible 1 mm thick bubble-free layers in the WAIS Divide ice core do not contain sufficient melt to alter the gas composition in the core, and do not cause artifacts or discontinuities in the gas chronology. The presence of these layers during winter, and the absence of anomalies in soluble gases, suggests that these layers can be formed by processes other than refreezing of meltwater. Consequently, the absence of bubbles in thin crusts is not in itself proof of a melt event. Article in Journal/Newspaper Greenland ice core Journal of Glaciology University of California: eScholarship Greenland |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
ice and climate ice core meltwater chemistry polar firn surface melt Physical Geography and Environmental Geoscience Meteorology & Atmospheric Sciences |
spellingShingle |
ice and climate ice core meltwater chemistry polar firn surface melt Physical Geography and Environmental Geoscience Meteorology & Atmospheric Sciences Orsi, Anais J Kawamura, Kenji Fegyveresi, John M Headly, Melissa A Alley, Richard B Severinghaus, Jeffrey P Differentiating bubble-free layers from melt layers in ice cores using noble gases |
topic_facet |
ice and climate ice core meltwater chemistry polar firn surface melt Physical Geography and Environmental Geoscience Meteorology & Atmospheric Sciences |
description |
Melt layers are clear indicators of extreme summer warmth on polar ice caps. The visual identification of refrozen meltwater as clear bubble-free layers cannot be used to study some past warm periods, because, in deeper ice, bubbles are lost to clathrate formation. We present here a reliable method to detect melt events, based on the analysis of Kr/Ar and Xe/Ar ratios in ice cores, and apply it to the detection of melt in clathrate ice from the Eemian at NEEM, Greenland. Additionally, melt layers in ice cores can compromise the integrity of the gas record by dissolving soluble gases, or by altering gas transport in the firn, which affects the gas chronology. We find that the easily visible 1 mm thick bubble-free layers in the WAIS Divide ice core do not contain sufficient melt to alter the gas composition in the core, and do not cause artifacts or discontinuities in the gas chronology. The presence of these layers during winter, and the absence of anomalies in soluble gases, suggests that these layers can be formed by processes other than refreezing of meltwater. Consequently, the absence of bubbles in thin crusts is not in itself proof of a melt event. |
format |
Article in Journal/Newspaper |
author |
Orsi, Anais J Kawamura, Kenji Fegyveresi, John M Headly, Melissa A Alley, Richard B Severinghaus, Jeffrey P |
author_facet |
Orsi, Anais J Kawamura, Kenji Fegyveresi, John M Headly, Melissa A Alley, Richard B Severinghaus, Jeffrey P |
author_sort |
Orsi, Anais J |
title |
Differentiating bubble-free layers from melt layers in ice cores using noble gases |
title_short |
Differentiating bubble-free layers from melt layers in ice cores using noble gases |
title_full |
Differentiating bubble-free layers from melt layers in ice cores using noble gases |
title_fullStr |
Differentiating bubble-free layers from melt layers in ice cores using noble gases |
title_full_unstemmed |
Differentiating bubble-free layers from melt layers in ice cores using noble gases |
title_sort |
differentiating bubble-free layers from melt layers in ice cores using noble gases |
publisher |
eScholarship, University of California |
publishDate |
2015 |
url |
https://escholarship.org/uc/item/0r15x7ww |
op_coverage |
585 - 594 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland ice core Journal of Glaciology |
genre_facet |
Greenland ice core Journal of Glaciology |
op_source |
Journal of Glaciology, vol 61, iss 227 |
op_relation |
qt0r15x7ww https://escholarship.org/uc/item/0r15x7ww |
op_rights |
public |
_version_ |
1769006310312902656 |