Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps
Crystal orientation fabric (COF) analysis provides information about the c-axis orientation of ice grains and the associated anisotropy and microstructural information about deformation and recrystallisation processes within the glacier. This information can be used to introduce modules that fully d...
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ftethz:oai:www.research-collection.ethz.ch:20.500.11850/474292 2023-08-20T04:07:12+02:00 Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps Hellmann, Sebastian id_orcid:0 000-0002-2365-7369 Kerch, Johanna Weikusat, Ilka Bauder, Andreas id_orcid:0 000-0001-7197-7706 Grab, Melchior id_orcid:0 000-0002-8293-4872 Jouvet, Guillaume Schwikowski, Margit Maurer, Hansruedi 2021 application/application/pdf https://hdl.handle.net/20.500.11850/474292 https://doi.org/10.3929/ethz-b-000474292 en eng Copernicus info:eu-repo/semantics/altIdentifier/doi/10.5194/tc-15-677-2021 info:eu-repo/semantics/altIdentifier/wos/000619678800001 info:eu-repo/grantAgreement/SNF/Projekte MINT/169329 http://hdl.handle.net/20.500.11850/474292 doi:10.3929/ethz-b-000474292 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International The Cryosphere, 15 (2) info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2021 ftethz https://doi.org/20.500.11850/47429210.3929/ethz-b-00047429210.5194/tc-15-677-2021 2023-07-30T23:53:20Z Crystal orientation fabric (COF) analysis provides information about the c-axis orientation of ice grains and the associated anisotropy and microstructural information about deformation and recrystallisation processes within the glacier. This information can be used to introduce modules that fully describe the microstructural anisotropy or at least direction-dependent enhancement factors for glacier modelling. The COF was studied at an ice core that was obtained from the temperate Rhonegletscher, located in the central Swiss Alps. Seven samples, extracted at depths between 2 and 79 m, were analysed with an automatic fabric analyser. The COF analysis revealed conspicuous four-maxima patterns of the c-axis orientations at all depths. Additional data, such as microstructural images, produced during the ice sample preparation process, were considered to interpret these patterns. Furthermore, repeated high-precision global navigation satellite system (GNSS) surveying allowed the local glacier flow direction to be determined. The relative movements of the individual surveying points indicated longitudinal compressive stresses parallel to the glacier flow. Finally, numerical modelling of the ice flow permitted estimation of the local stress distribution. An integrated analysis of all the data sets provided indications and suggestions for the development of the four-maxima patterns. The centroid of the four-maxima patterns of the individual core samples and the coinciding maximum eigenvector approximately align with the compressive stress directions obtained from numerical modelling with an exception for the deepest sample. The clustering of the c axes in four maxima surrounding the predominant compressive stress direction is most likely the result of a fast migration recrystallisation. This interpretation is supported by air bubble analysis of large-area scanning macroscope (LASM) images. Our results indicate that COF studies, which have so far predominantly been performed on cold ice samples from the polar regions, ... Article in Journal/Newspaper ice core The Cryosphere ETH Zürich Research Collection |
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Open Polar |
collection |
ETH Zürich Research Collection |
op_collection_id |
ftethz |
language |
English |
description |
Crystal orientation fabric (COF) analysis provides information about the c-axis orientation of ice grains and the associated anisotropy and microstructural information about deformation and recrystallisation processes within the glacier. This information can be used to introduce modules that fully describe the microstructural anisotropy or at least direction-dependent enhancement factors for glacier modelling. The COF was studied at an ice core that was obtained from the temperate Rhonegletscher, located in the central Swiss Alps. Seven samples, extracted at depths between 2 and 79 m, were analysed with an automatic fabric analyser. The COF analysis revealed conspicuous four-maxima patterns of the c-axis orientations at all depths. Additional data, such as microstructural images, produced during the ice sample preparation process, were considered to interpret these patterns. Furthermore, repeated high-precision global navigation satellite system (GNSS) surveying allowed the local glacier flow direction to be determined. The relative movements of the individual surveying points indicated longitudinal compressive stresses parallel to the glacier flow. Finally, numerical modelling of the ice flow permitted estimation of the local stress distribution. An integrated analysis of all the data sets provided indications and suggestions for the development of the four-maxima patterns. The centroid of the four-maxima patterns of the individual core samples and the coinciding maximum eigenvector approximately align with the compressive stress directions obtained from numerical modelling with an exception for the deepest sample. The clustering of the c axes in four maxima surrounding the predominant compressive stress direction is most likely the result of a fast migration recrystallisation. This interpretation is supported by air bubble analysis of large-area scanning macroscope (LASM) images. Our results indicate that COF studies, which have so far predominantly been performed on cold ice samples from the polar regions, ... |
format |
Article in Journal/Newspaper |
author |
Hellmann, Sebastian id_orcid:0 000-0002-2365-7369 Kerch, Johanna Weikusat, Ilka Bauder, Andreas id_orcid:0 000-0001-7197-7706 Grab, Melchior id_orcid:0 000-0002-8293-4872 Jouvet, Guillaume Schwikowski, Margit Maurer, Hansruedi |
spellingShingle |
Hellmann, Sebastian id_orcid:0 000-0002-2365-7369 Kerch, Johanna Weikusat, Ilka Bauder, Andreas id_orcid:0 000-0001-7197-7706 Grab, Melchior id_orcid:0 000-0002-8293-4872 Jouvet, Guillaume Schwikowski, Margit Maurer, Hansruedi Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps |
author_facet |
Hellmann, Sebastian id_orcid:0 000-0002-2365-7369 Kerch, Johanna Weikusat, Ilka Bauder, Andreas id_orcid:0 000-0001-7197-7706 Grab, Melchior id_orcid:0 000-0002-8293-4872 Jouvet, Guillaume Schwikowski, Margit Maurer, Hansruedi |
author_sort |
Hellmann, Sebastian |
title |
Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps |
title_short |
Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps |
title_full |
Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps |
title_fullStr |
Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps |
title_full_unstemmed |
Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps |
title_sort |
crystallographic analysis of temperate ice on rhonegletscher, swiss alps |
publisher |
Copernicus |
publishDate |
2021 |
url |
https://hdl.handle.net/20.500.11850/474292 https://doi.org/10.3929/ethz-b-000474292 |
genre |
ice core The Cryosphere |
genre_facet |
ice core The Cryosphere |
op_source |
The Cryosphere, 15 (2) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/tc-15-677-2021 info:eu-repo/semantics/altIdentifier/wos/000619678800001 info:eu-repo/grantAgreement/SNF/Projekte MINT/169329 http://hdl.handle.net/20.500.11850/474292 doi:10.3929/ethz-b-000474292 |
op_rights |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International |
op_doi |
https://doi.org/20.500.11850/47429210.3929/ethz-b-00047429210.5194/tc-15-677-2021 |
_version_ |
1774718682832830464 |