Physical analysis of an Antarctic ice core-towards an integration of micro- and macrodynamics of polar ice
Microstructures from deep ice cores reflect the dynamic conditions of the drill location as well as the thermodynamic history of the drill site and catchment area in great detail. Ice core parameters (crystal lattice-preferred orientation (LPO), grain size, grain shape), mesostructures (visual strat...
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Online Access: | https://resolver.sub.uni-goettingen.de/purl?gro-2/43241 https://resolver.sub.uni-goettingen.de/purl?gs-1/14306 https://doi.org/10.1098/rsta.2015.0347 |
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ftsubgoettingen:oai:publications.goettingen-research-online.de:2/43241 2023-09-05T13:13:05+02:00 Physical analysis of an Antarctic ice core-towards an integration of micro- and macrodynamics of polar ice Weikusat, Ilka Jansen, Daniela Binder, Tobias Eichler, Jan Faria, Sergio H. Wilhelms, Frank Kipfstuhl, Sepp Sheldon, Simon G. Miller, Heinrich Dahl-Jensen, Dorthe Kleiner, Thomas 2017 https://resolver.sub.uni-goettingen.de/purl?gro-2/43241 https://resolver.sub.uni-goettingen.de/purl?gs-1/14306 https://doi.org/10.1098/rsta.2015.0347 unknown Royal Soc 1471-2962 1364-503X https://resolver.sub.uni-goettingen.de/purl?gro-2/43241 doi:10.1098/rsta.2015.0347 000391840100005 https://resolver.sub.uni-goettingen.de/purl?gs-1/14306 CC BY 4.0 https://creativecommons.org/licenses/by/4.0/ journal_article published yes published_version 2017 ftsubgoettingen https://doi.org/10.1098/rsta.2015.0347 2023-08-20T22:13:35Z Microstructures from deep ice cores reflect the dynamic conditions of the drill location as well as the thermodynamic history of the drill site and catchment area in great detail. Ice core parameters (crystal lattice-preferred orientation (LPO), grain size, grain shape), mesostructures (visual stratigraphy) as well as borehole deformation were measured in a deep ice core drilled at Kohnen Station, Dronning Maud Land (DML), Antarctica. These observations are used to characterize the local dynamic setting and its rheological as well as microstructural effects at the EDML ice core drilling site (European Project for Ice Coring in Antarctica in DML). The results suggest a division of the core into five distinct sections, interpreted as the effects of changing deformation boundary conditions from triaxial deformation with horizontal extension to bedrock-parallel shear. Region 1 (uppermost approx. 450m depth) with still small macroscopic strain is dominated by compression of bubbles and strong strain and recrystallization localization. Region 2 (approx. 450-1700m depth) shows a girdle-type LPO with the girdle plane being perpendicular to grain elongations, which indicates triaxial deformation with dominating horizontal extension. In this region (approx. 1000m depth), the first subtle traces of shear deformation are observed in the shape-preferred orientation (SPO) by inclination of the grain elongation. Region 3 (approx. 1700-2030m depth) represents a transitional regime between triaxial deformation and dominance of shear, which becomes apparent in the progression of the girdle to a single maximum LPO and increasing obliqueness of grain elongations. The fully developed single maximum LPO in region 4 (approx. 2030-2385m depth) is an indicator of shear dominance. Region 5 (below approx. 2385m depth) is marked by signs of strong shear, such as strong SPO values of grain elongation and strong kink folding of visual layers. The details of structural observations are compared with results from a numerical ice sheet model ... Article in Journal/Newspaper Antarc* Antarctic Antarctica DML Dronning Maud Land ice core Ice Sheet Georg-August-Universität Göttingen: GoeScholar Antarctic Dronning Maud Land Kohnen ENVELOPE(0.000,0.000,-75.000,-75.000) Kohnen Station ENVELOPE(0.000,0.000,-75.000,-75.000) |
institution |
Open Polar |
collection |
Georg-August-Universität Göttingen: GoeScholar |
op_collection_id |
ftsubgoettingen |
language |
unknown |
description |
Microstructures from deep ice cores reflect the dynamic conditions of the drill location as well as the thermodynamic history of the drill site and catchment area in great detail. Ice core parameters (crystal lattice-preferred orientation (LPO), grain size, grain shape), mesostructures (visual stratigraphy) as well as borehole deformation were measured in a deep ice core drilled at Kohnen Station, Dronning Maud Land (DML), Antarctica. These observations are used to characterize the local dynamic setting and its rheological as well as microstructural effects at the EDML ice core drilling site (European Project for Ice Coring in Antarctica in DML). The results suggest a division of the core into five distinct sections, interpreted as the effects of changing deformation boundary conditions from triaxial deformation with horizontal extension to bedrock-parallel shear. Region 1 (uppermost approx. 450m depth) with still small macroscopic strain is dominated by compression of bubbles and strong strain and recrystallization localization. Region 2 (approx. 450-1700m depth) shows a girdle-type LPO with the girdle plane being perpendicular to grain elongations, which indicates triaxial deformation with dominating horizontal extension. In this region (approx. 1000m depth), the first subtle traces of shear deformation are observed in the shape-preferred orientation (SPO) by inclination of the grain elongation. Region 3 (approx. 1700-2030m depth) represents a transitional regime between triaxial deformation and dominance of shear, which becomes apparent in the progression of the girdle to a single maximum LPO and increasing obliqueness of grain elongations. The fully developed single maximum LPO in region 4 (approx. 2030-2385m depth) is an indicator of shear dominance. Region 5 (below approx. 2385m depth) is marked by signs of strong shear, such as strong SPO values of grain elongation and strong kink folding of visual layers. The details of structural observations are compared with results from a numerical ice sheet model ... |
format |
Article in Journal/Newspaper |
author |
Weikusat, Ilka Jansen, Daniela Binder, Tobias Eichler, Jan Faria, Sergio H. Wilhelms, Frank Kipfstuhl, Sepp Sheldon, Simon G. Miller, Heinrich Dahl-Jensen, Dorthe Kleiner, Thomas |
spellingShingle |
Weikusat, Ilka Jansen, Daniela Binder, Tobias Eichler, Jan Faria, Sergio H. Wilhelms, Frank Kipfstuhl, Sepp Sheldon, Simon G. Miller, Heinrich Dahl-Jensen, Dorthe Kleiner, Thomas Physical analysis of an Antarctic ice core-towards an integration of micro- and macrodynamics of polar ice |
author_facet |
Weikusat, Ilka Jansen, Daniela Binder, Tobias Eichler, Jan Faria, Sergio H. Wilhelms, Frank Kipfstuhl, Sepp Sheldon, Simon G. Miller, Heinrich Dahl-Jensen, Dorthe Kleiner, Thomas |
author_sort |
Weikusat, Ilka |
title |
Physical analysis of an Antarctic ice core-towards an integration of micro- and macrodynamics of polar ice |
title_short |
Physical analysis of an Antarctic ice core-towards an integration of micro- and macrodynamics of polar ice |
title_full |
Physical analysis of an Antarctic ice core-towards an integration of micro- and macrodynamics of polar ice |
title_fullStr |
Physical analysis of an Antarctic ice core-towards an integration of micro- and macrodynamics of polar ice |
title_full_unstemmed |
Physical analysis of an Antarctic ice core-towards an integration of micro- and macrodynamics of polar ice |
title_sort |
physical analysis of an antarctic ice core-towards an integration of micro- and macrodynamics of polar ice |
publisher |
Royal Soc |
publishDate |
2017 |
url |
https://resolver.sub.uni-goettingen.de/purl?gro-2/43241 https://resolver.sub.uni-goettingen.de/purl?gs-1/14306 https://doi.org/10.1098/rsta.2015.0347 |
long_lat |
ENVELOPE(0.000,0.000,-75.000,-75.000) ENVELOPE(0.000,0.000,-75.000,-75.000) |
geographic |
Antarctic Dronning Maud Land Kohnen Kohnen Station |
geographic_facet |
Antarctic Dronning Maud Land Kohnen Kohnen Station |
genre |
Antarc* Antarctic Antarctica DML Dronning Maud Land ice core Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica DML Dronning Maud Land ice core Ice Sheet |
op_relation |
1471-2962 1364-503X https://resolver.sub.uni-goettingen.de/purl?gro-2/43241 doi:10.1098/rsta.2015.0347 000391840100005 https://resolver.sub.uni-goettingen.de/purl?gs-1/14306 |
op_rights |
CC BY 4.0 https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1098/rsta.2015.0347 |
_version_ |
1776203407801974784 |