Pore morphology of polar firn around closure revealed by X-ray tomography
International audience Understanding the slow densification process of polar firn into ice is essential in order to constrain the age difference between the ice matrix and entrapped gases. The progressive microstructure evolution of the firn column with depth leads to pore closure and gas entrapment...
Published in: | The Cryosphere |
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Main Authors: | , , , , , |
Other Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2018
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Online Access: | https://hal.science/hal-01864373 https://hal.science/hal-01864373/document https://hal.science/hal-01864373/file/Burr%20et%20al._2018_Pore%20morphology%20of%20polar%20firn%20around%20closure%20revealed%20by%20X-ray%20tomography.pdf https://doi.org/10.5194/tc-12-2481-2018 |
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Open Polar |
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Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
[SPI.MAT]Engineering Sciences [physics]/Materials [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology [SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph] |
spellingShingle |
[SPI.MAT]Engineering Sciences [physics]/Materials [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology [SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph] Burr, Alexis Ballot, Clément Lhuissier, Pierre Martinerie, Patricia L. Martin, Christophe Philip, Armelle Pore morphology of polar firn around closure revealed by X-ray tomography |
topic_facet |
[SPI.MAT]Engineering Sciences [physics]/Materials [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology [SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph] |
description |
International audience Understanding the slow densification process of polar firn into ice is essential in order to constrain the age difference between the ice matrix and entrapped gases. The progressive microstructure evolution of the firn column with depth leads to pore closure and gas entrapment. Air transport models in the firn usually include a closed porosity profile based on available data. Pycnometry or melting–refreezing techniques have been used to obtain the ratio of closed to total porosity and air content in closed pores, respectively. X-ray-computed tomography is complementary to these methods , as it enables one to obtain the full pore network in 3-D. This study takes advantage of this nondestructive technique to discuss the morphological evolution of pores on four different Antarctic sites. The computation of refined geometrical parameters for the very cold polar sites Dome C and Lock In (the two Antarctic plateau sites studied here) provides new information that could be used in further studies. The comparison of these two sites shows a more tortuous pore network at Lock In than at Dome C, which should result in older gas ages in deep firn at Lock In. A comprehensive estimation of the different errors related to X-ray tomography and to the sample variability has been performed. The procedure described here may be used as a guideline for further experimental characterization of firn samples. We show that the closed-to-total porosity ratio, which is classically used for the detection of pore closure, is strongly affected by the sample size, the image reconstruction, and spatial heterogeneities. In this work, we introduce an alternative parameter, the connec-tivity index, which is practically independent of sample size and image acquisition conditions, and that accurately predicts the close-off depth and density. Its strength also lies in its simple computation, without any assumption of the pore status (open or close). The close-off prediction is obtained for Dome C and Lock In, without any ... |
author2 |
Science et Ingénierie des Matériaux et Procédés (SIMaP ) Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ) Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ) |
format |
Article in Journal/Newspaper |
author |
Burr, Alexis Ballot, Clément Lhuissier, Pierre Martinerie, Patricia L. Martin, Christophe Philip, Armelle |
author_facet |
Burr, Alexis Ballot, Clément Lhuissier, Pierre Martinerie, Patricia L. Martin, Christophe Philip, Armelle |
author_sort |
Burr, Alexis |
title |
Pore morphology of polar firn around closure revealed by X-ray tomography |
title_short |
Pore morphology of polar firn around closure revealed by X-ray tomography |
title_full |
Pore morphology of polar firn around closure revealed by X-ray tomography |
title_fullStr |
Pore morphology of polar firn around closure revealed by X-ray tomography |
title_full_unstemmed |
Pore morphology of polar firn around closure revealed by X-ray tomography |
title_sort |
pore morphology of polar firn around closure revealed by x-ray tomography |
publisher |
HAL CCSD |
publishDate |
2018 |
url |
https://hal.science/hal-01864373 https://hal.science/hal-01864373/document https://hal.science/hal-01864373/file/Burr%20et%20al._2018_Pore%20morphology%20of%20polar%20firn%20around%20closure%20revealed%20by%20X-ray%20tomography.pdf https://doi.org/10.5194/tc-12-2481-2018 |
genre |
Antarc* Antarctic The Cryosphere |
genre_facet |
Antarc* Antarctic The Cryosphere |
op_source |
ISSN: 1994-0424 EISSN: 1994-0416 The Cryosphere https://hal.science/hal-01864373 The Cryosphere, 2018, 12 (7), pp.2481-2500. ⟨10.5194/tc-12-2481-2018⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/tc-12-2481-2018 hal-01864373 https://hal.science/hal-01864373 https://hal.science/hal-01864373/document https://hal.science/hal-01864373/file/Burr%20et%20al._2018_Pore%20morphology%20of%20polar%20firn%20around%20closure%20revealed%20by%20X-ray%20tomography.pdf doi:10.5194/tc-12-2481-2018 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.5194/tc-12-2481-2018 |
container_title |
The Cryosphere |
container_volume |
12 |
container_issue |
7 |
container_start_page |
2481 |
op_container_end_page |
2500 |
_version_ |
1797572541410181120 |
spelling |
ftinsu:oai:HAL:hal-01864373v1 2024-04-28T08:00:13+00:00 Pore morphology of polar firn around closure revealed by X-ray tomography Burr, Alexis Ballot, Clément Lhuissier, Pierre Martinerie, Patricia L. Martin, Christophe Philip, Armelle Science et Ingénierie des Matériaux et Procédés (SIMaP ) Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ) Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ) 2018 https://hal.science/hal-01864373 https://hal.science/hal-01864373/document https://hal.science/hal-01864373/file/Burr%20et%20al._2018_Pore%20morphology%20of%20polar%20firn%20around%20closure%20revealed%20by%20X-ray%20tomography.pdf https://doi.org/10.5194/tc-12-2481-2018 en eng HAL CCSD Copernicus info:eu-repo/semantics/altIdentifier/doi/10.5194/tc-12-2481-2018 hal-01864373 https://hal.science/hal-01864373 https://hal.science/hal-01864373/document https://hal.science/hal-01864373/file/Burr%20et%20al._2018_Pore%20morphology%20of%20polar%20firn%20around%20closure%20revealed%20by%20X-ray%20tomography.pdf doi:10.5194/tc-12-2481-2018 info:eu-repo/semantics/OpenAccess ISSN: 1994-0424 EISSN: 1994-0416 The Cryosphere https://hal.science/hal-01864373 The Cryosphere, 2018, 12 (7), pp.2481-2500. ⟨10.5194/tc-12-2481-2018⟩ [SPI.MAT]Engineering Sciences [physics]/Materials [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology [SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph] info:eu-repo/semantics/article Journal articles 2018 ftinsu https://doi.org/10.5194/tc-12-2481-2018 2024-04-05T00:45:22Z International audience Understanding the slow densification process of polar firn into ice is essential in order to constrain the age difference between the ice matrix and entrapped gases. The progressive microstructure evolution of the firn column with depth leads to pore closure and gas entrapment. Air transport models in the firn usually include a closed porosity profile based on available data. Pycnometry or melting–refreezing techniques have been used to obtain the ratio of closed to total porosity and air content in closed pores, respectively. X-ray-computed tomography is complementary to these methods , as it enables one to obtain the full pore network in 3-D. This study takes advantage of this nondestructive technique to discuss the morphological evolution of pores on four different Antarctic sites. The computation of refined geometrical parameters for the very cold polar sites Dome C and Lock In (the two Antarctic plateau sites studied here) provides new information that could be used in further studies. The comparison of these two sites shows a more tortuous pore network at Lock In than at Dome C, which should result in older gas ages in deep firn at Lock In. A comprehensive estimation of the different errors related to X-ray tomography and to the sample variability has been performed. The procedure described here may be used as a guideline for further experimental characterization of firn samples. We show that the closed-to-total porosity ratio, which is classically used for the detection of pore closure, is strongly affected by the sample size, the image reconstruction, and spatial heterogeneities. In this work, we introduce an alternative parameter, the connec-tivity index, which is practically independent of sample size and image acquisition conditions, and that accurately predicts the close-off depth and density. Its strength also lies in its simple computation, without any assumption of the pore status (open or close). The close-off prediction is obtained for Dome C and Lock In, without any ... Article in Journal/Newspaper Antarc* Antarctic The Cryosphere Institut national des sciences de l'Univers: HAL-INSU The Cryosphere 12 7 2481 2500 |