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...

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Published in:The Cryosphere
Main Authors: S. Hellmann, J. Kerch, I. Weikusat, A. Bauder, M. Grab, G. Jouvet, M. Schwikowski, H. Maurer
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2021
Subjects:
Online Access:https://doi.org/10.5194/tc-15-677-2021
https://doaj.org/article/9a31dfd48dc54ec6943c515b0ac80ea3
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spelling ftdoajarticles:oai:doaj.org/article:9a31dfd48dc54ec6943c515b0ac80ea3 2023-05-15T16:39:20+02:00 Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps S. Hellmann J. Kerch I. Weikusat A. Bauder M. Grab G. Jouvet M. Schwikowski H. Maurer 2021-02-01T00:00:00Z https://doi.org/10.5194/tc-15-677-2021 https://doaj.org/article/9a31dfd48dc54ec6943c515b0ac80ea3 EN eng Copernicus Publications https://tc.copernicus.org/articles/15/677/2021/tc-15-677-2021.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-15-677-2021 1994-0416 1994-0424 https://doaj.org/article/9a31dfd48dc54ec6943c515b0ac80ea3 The Cryosphere, Vol 15, Pp 677-694 (2021) Environmental sciences GE1-350 Geology QE1-996.5 article 2021 ftdoajarticles https://doi.org/10.5194/tc-15-677-2021 2022-12-30T22:02:41Z 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 Directory of Open Access Journals: DOAJ Articles The Cryosphere 15 2 677 694
institution 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
S. Hellmann
J. Kerch
I. Weikusat
A. Bauder
M. Grab
G. Jouvet
M. Schwikowski
H. Maurer
Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps
topic_facet Environmental sciences
GE1-350
Geology
QE1-996.5
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 S. Hellmann
J. Kerch
I. Weikusat
A. Bauder
M. Grab
G. Jouvet
M. Schwikowski
H. Maurer
author_facet S. Hellmann
J. Kerch
I. Weikusat
A. Bauder
M. Grab
G. Jouvet
M. Schwikowski
H. Maurer
author_sort S. Hellmann
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 Publications
publishDate 2021
url https://doi.org/10.5194/tc-15-677-2021
https://doaj.org/article/9a31dfd48dc54ec6943c515b0ac80ea3
genre ice core
The Cryosphere
genre_facet ice core
The Cryosphere
op_source The Cryosphere, Vol 15, Pp 677-694 (2021)
op_relation https://tc.copernicus.org/articles/15/677/2021/tc-15-677-2021.pdf
https://doaj.org/toc/1994-0416
https://doaj.org/toc/1994-0424
doi:10.5194/tc-15-677-2021
1994-0416
1994-0424
https://doaj.org/article/9a31dfd48dc54ec6943c515b0ac80ea3
op_doi https://doi.org/10.5194/tc-15-677-2021
container_title The Cryosphere
container_volume 15
container_issue 2
container_start_page 677
op_container_end_page 694
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