Texture of the Upper 1000 m in the GRIP and NorthGRIP Ice Cores
In this study we discuss new and published profiles of c-axis fabric and size distributions of a large number of crystals in the upper 1000 m of the Greenland GRIP and NorthGRIP ice cores as obtained with an automatic c-axis fabric analyzer. We show that in both cores the fabric is strongly anisotro...
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Institute of Low Temperature Science, Hokkaido University
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fthokunivhus:oai:eprints.lib.hokudai.ac.jp:2115/45437 2023-05-15T16:27:10+02:00 Texture of the Upper 1000 m in the GRIP and NorthGRIP Ice Cores Svensson, Anders Durand, Gaël Mathiesen, Joachim Persson, Asbjørn Dahl-Jensen, Dorthe http://hdl.handle.net/2115/45437 eng eng Institute of Low Temperature Science, Hokkaido University Physics of Ice Core Records II : Papers collected after the 2nd International Workshop on Physics of Ice Core Records, held in Sapporo, Japan, 2-6 February 2007. Edited by Takeo Hondoh http://hdl.handle.net/2115/45437 ice core ice crystal texture fabric Greenland 400 bulletin (article) fthokunivhus 2022-11-18T01:02:09Z In this study we discuss new and published profiles of c-axis fabric and size distributions of a large number of crystals in the upper 1000 m of the Greenland GRIP and NorthGRIP ice cores as obtained with an automatic c-axis fabric analyzer. We show that in both cores the fabric is strongly anisotropic already just below the firn (about 110 m depth) with a degree of orientation around 30%. We determine the mean crystal area profiles which are somewhat contrasting to earlier findings based on manual measurements. The crystal size distributions are compared to a simple ID model which takes into account crystal growth and polygonization (rotation recrystallization). The model suggests that the crystal size distribution develops into a Bessel type distribution that differs from the commonly applied log normal distribution. Finally. we combine the fabric and microstructure results to determine the sub-grain boundaries in the GRIP samples. Both the size distribution model and the sub-grain study suggest that polygonization is significant already below the firn and that the physical processes governing the conventionally adapted 'normal grain growth' and 'polygonization' regimes are identical. The new measurements provide a dataset for ice sheet models that take into account the anisotropy of the Greenland ice sheet. I. Microphysical properties, deformation, texture and grain growth Article in Journal/Newspaper Greenland GRIP ice core Ice Sheet Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) Greenland |
institution |
Open Polar |
collection |
Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) |
op_collection_id |
fthokunivhus |
language |
English |
topic |
ice core ice crystal texture fabric Greenland 400 |
spellingShingle |
ice core ice crystal texture fabric Greenland 400 Svensson, Anders Durand, Gaël Mathiesen, Joachim Persson, Asbjørn Dahl-Jensen, Dorthe Texture of the Upper 1000 m in the GRIP and NorthGRIP Ice Cores |
topic_facet |
ice core ice crystal texture fabric Greenland 400 |
description |
In this study we discuss new and published profiles of c-axis fabric and size distributions of a large number of crystals in the upper 1000 m of the Greenland GRIP and NorthGRIP ice cores as obtained with an automatic c-axis fabric analyzer. We show that in both cores the fabric is strongly anisotropic already just below the firn (about 110 m depth) with a degree of orientation around 30%. We determine the mean crystal area profiles which are somewhat contrasting to earlier findings based on manual measurements. The crystal size distributions are compared to a simple ID model which takes into account crystal growth and polygonization (rotation recrystallization). The model suggests that the crystal size distribution develops into a Bessel type distribution that differs from the commonly applied log normal distribution. Finally. we combine the fabric and microstructure results to determine the sub-grain boundaries in the GRIP samples. Both the size distribution model and the sub-grain study suggest that polygonization is significant already below the firn and that the physical processes governing the conventionally adapted 'normal grain growth' and 'polygonization' regimes are identical. The new measurements provide a dataset for ice sheet models that take into account the anisotropy of the Greenland ice sheet. I. Microphysical properties, deformation, texture and grain growth |
format |
Article in Journal/Newspaper |
author |
Svensson, Anders Durand, Gaël Mathiesen, Joachim Persson, Asbjørn Dahl-Jensen, Dorthe |
author_facet |
Svensson, Anders Durand, Gaël Mathiesen, Joachim Persson, Asbjørn Dahl-Jensen, Dorthe |
author_sort |
Svensson, Anders |
title |
Texture of the Upper 1000 m in the GRIP and NorthGRIP Ice Cores |
title_short |
Texture of the Upper 1000 m in the GRIP and NorthGRIP Ice Cores |
title_full |
Texture of the Upper 1000 m in the GRIP and NorthGRIP Ice Cores |
title_fullStr |
Texture of the Upper 1000 m in the GRIP and NorthGRIP Ice Cores |
title_full_unstemmed |
Texture of the Upper 1000 m in the GRIP and NorthGRIP Ice Cores |
title_sort |
texture of the upper 1000 m in the grip and northgrip ice cores |
publisher |
Institute of Low Temperature Science, Hokkaido University |
url |
http://hdl.handle.net/2115/45437 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland GRIP ice core Ice Sheet |
genre_facet |
Greenland GRIP ice core Ice Sheet |
op_relation |
Physics of Ice Core Records II : Papers collected after the 2nd International Workshop on Physics of Ice Core Records, held in Sapporo, Japan, 2-6 February 2007. Edited by Takeo Hondoh http://hdl.handle.net/2115/45437 |
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1766016254987993088 |