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...
Published in: | Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |
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Online Access: | http://dx.doi.org/10.1098/rsta.2015.0347 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.2015.0347 https://royalsocietypublishing.org/doi/full-xml/10.1098/rsta.2015.0347 |
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crroyalsociety:10.1098/rsta.2015.0347 2024-09-30T14:25:12+00:00 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, Sérgio H. Wilhelms, Frank Kipfstuhl, Sepp Sheldon, Simon Miller, Heinrich Dahl-Jensen, Dorthe Kleiner, Thomas HGF SPP 1158 DFG Ramón y Cajal Research 2017 http://dx.doi.org/10.1098/rsta.2015.0347 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.2015.0347 https://royalsocietypublishing.org/doi/full-xml/10.1098/rsta.2015.0347 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences volume 375, issue 2086, page 20150347 ISSN 1364-503X 1471-2962 journal-article 2017 crroyalsociety https://doi.org/10.1098/rsta.2015.0347 2024-09-17T04:34:45Z 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. 450 m depth) with still small macroscopic strain is dominated by compression of bubbles and strong strain and recrystallization localization. Region 2 (approx. 450–1700 m 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. 1000 m 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. 1700–2030 m 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. 2030–2385 m depth) is an indicator of shear dominance. Region 5 (below approx. 2385 m 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 ... Article in Journal/Newspaper Antarc* Antarctic Antarctica DML Dronning Maud Land ice core Ice Sheet The Royal Society 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) Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375 2086 20150347 |
institution |
Open Polar |
collection |
The Royal Society |
op_collection_id |
crroyalsociety |
language |
English |
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. 450 m depth) with still small macroscopic strain is dominated by compression of bubbles and strong strain and recrystallization localization. Region 2 (approx. 450–1700 m 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. 1000 m 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. 1700–2030 m 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. 2030–2385 m depth) is an indicator of shear dominance. Region 5 (below approx. 2385 m 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 ... |
author2 |
HGF SPP 1158 DFG Ramón y Cajal Research |
format |
Article in Journal/Newspaper |
author |
Weikusat, Ilka Jansen, Daniela Binder, Tobias Eichler, Jan Faria, Sérgio H. Wilhelms, Frank Kipfstuhl, Sepp Sheldon, Simon Miller, Heinrich Dahl-Jensen, Dorthe Kleiner, Thomas |
spellingShingle |
Weikusat, Ilka Jansen, Daniela Binder, Tobias Eichler, Jan Faria, Sérgio H. Wilhelms, Frank Kipfstuhl, Sepp Sheldon, Simon 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, Sérgio H. Wilhelms, Frank Kipfstuhl, Sepp Sheldon, Simon 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 |
The Royal Society |
publishDate |
2017 |
url |
http://dx.doi.org/10.1098/rsta.2015.0347 https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.2015.0347 https://royalsocietypublishing.org/doi/full-xml/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_source |
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences volume 375, issue 2086, page 20150347 ISSN 1364-503X 1471-2962 |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rsta.2015.0347 |
container_title |
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |
container_volume |
375 |
container_issue |
2086 |
container_start_page |
20150347 |
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1811643896219828224 |