Fabric along the NEEM ice core, Greenland, and its comparison with GRIP and NGRIP ice cores
Fabric (distribution of crystallographic orientations) along the full NEEM ice core, Greenland was measured in the field by an automatic ice texture analyzer every 10 m, from 33 m down to 2461 m depth. The fabric evolves from a slightly anisotropic fabric at the top, toward a strong single maximum a...
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-07-01
|
| Series: | The Cryosphere |
| Online Access: | http://www.the-cryosphere.net/8/1129/2014/tc-8-1129-2014.pdf |
| _version_ | 1818887510231613440 |
|---|---|
| author | M. Montagnat N. Azuma D. Dahl-Jensen J. Eichler S. Fujita F. Gillet-Chaulet S. Kipfstuhl D. Samyn A. Svensson I. Weikusat |
| author_facet | M. Montagnat N. Azuma D. Dahl-Jensen J. Eichler S. Fujita F. Gillet-Chaulet S. Kipfstuhl D. Samyn A. Svensson I. Weikusat |
| author_sort | M. Montagnat |
| collection | DOAJ |
| description | Fabric (distribution of crystallographic orientations) along the full NEEM
ice core, Greenland was measured in the field by an automatic ice texture
analyzer every 10 m, from 33 m down to 2461 m depth. The fabric evolves
from a slightly anisotropic fabric at the top, toward a strong single maximum
at about 2300 m, which is typical of a deformation pattern mostly driven by
uniaxial compression and simple shearing. A sharp increase in the fabric
strengthening rate is observed at the Holocene to Wisconsin (HW) climatic
transition. From a simple model we estimate that this depth is located at a
transition from a state dominated by vertical compression to a state
dominated by vertical shear. Comparisons are made to two others ice cores
drilled along the same ridge; the GRIP ice core, drilled at the summit of the
ice sheet, and the NGRIP ice core, drilled 325 km to the NNW of the summit
along the ridge, and 365 km upstream from NEEM. This comparison tends to
demonstrate that the ice viscosity change with the HW climatic transition
must be associated with the shear-dominated state to induce the abrupt fabric
strengthening observed at NEEM. This comparison therefore reflects the
increasing role of shear deformation on the coring site when moving NW along
the ridge from GRIP to NGRIP and NEEM. The difference in fabric profiles
between NEEM and NGRIP also evidences a stronger lateral extension associated
with a sharper ridge at NGRIP. Further along the core, centimeter scale
abrupt texture (fabric and microstructure) variations are observed in the
bottom part of the core. Their positions are in good agreement with the
observed folding layers in Dahl-Jensen et al. (2013). |
| first_indexed | 2024-12-19T16:38:22Z |
| format | Article |
| id | doaj.art-2b0ad529d52349c7ac52064d5bc08fe0 |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-12-19T16:38:22Z |
| publishDate | 2014-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-2b0ad529d52349c7ac52064d5bc08fe02022-12-21T20:13:54ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242014-07-01841129113810.5194/tc-8-1129-2014Fabric along the NEEM ice core, Greenland, and its comparison with GRIP and NGRIP ice coresM. Montagnat0N. Azuma1D. Dahl-Jensen2J. Eichler3S. Fujita4F. Gillet-Chaulet5S. Kipfstuhl6D. Samyn7A. Svensson8I. Weikusat9CNRS, LGGE, UMR5183, 38041 Grenoble, FranceDepartment of Mechanical Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Niigata, JapanNiels Bohr Institute, Ice and Climate Research, University of Copenhagen, Juliane Maries Vej 30, <br/>2100 Copenhagen, DenmarkAlfred Wegener Institute for Polar and Marine Research, Columbusstrasse, 27568 Bremerhaven, GermanyNational Institute of Polar Research, Research Organization of Information and Systems (ROIS), Midori-chou 10-3, Tachikawa, Tokyo, 190-8518, JapanCNRS, LGGE, UMR5183, 38041 Grenoble, FranceAlfred Wegener Institute for Polar and Marine Research, Columbusstrasse, 27568 Bremerhaven, GermanyDepartment of Mechanical Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Niigata, JapanNiels Bohr Institute, Ice and Climate Research, University of Copenhagen, Juliane Maries Vej 30, <br/>2100 Copenhagen, DenmarkAlfred Wegener Institute for Polar and Marine Research, Columbusstrasse, 27568 Bremerhaven, GermanyFabric (distribution of crystallographic orientations) along the full NEEM ice core, Greenland was measured in the field by an automatic ice texture analyzer every 10 m, from 33 m down to 2461 m depth. The fabric evolves from a slightly anisotropic fabric at the top, toward a strong single maximum at about 2300 m, which is typical of a deformation pattern mostly driven by uniaxial compression and simple shearing. A sharp increase in the fabric strengthening rate is observed at the Holocene to Wisconsin (HW) climatic transition. From a simple model we estimate that this depth is located at a transition from a state dominated by vertical compression to a state dominated by vertical shear. Comparisons are made to two others ice cores drilled along the same ridge; the GRIP ice core, drilled at the summit of the ice sheet, and the NGRIP ice core, drilled 325 km to the NNW of the summit along the ridge, and 365 km upstream from NEEM. This comparison tends to demonstrate that the ice viscosity change with the HW climatic transition must be associated with the shear-dominated state to induce the abrupt fabric strengthening observed at NEEM. This comparison therefore reflects the increasing role of shear deformation on the coring site when moving NW along the ridge from GRIP to NGRIP and NEEM. The difference in fabric profiles between NEEM and NGRIP also evidences a stronger lateral extension associated with a sharper ridge at NGRIP. Further along the core, centimeter scale abrupt texture (fabric and microstructure) variations are observed in the bottom part of the core. Their positions are in good agreement with the observed folding layers in Dahl-Jensen et al. (2013).http://www.the-cryosphere.net/8/1129/2014/tc-8-1129-2014.pdf |
| spellingShingle | M. Montagnat N. Azuma D. Dahl-Jensen J. Eichler S. Fujita F. Gillet-Chaulet S. Kipfstuhl D. Samyn A. Svensson I. Weikusat Fabric along the NEEM ice core, Greenland, and its comparison with GRIP and NGRIP ice cores The Cryosphere |
| title | Fabric along the NEEM ice core, Greenland, and its comparison with GRIP and NGRIP ice cores |
| title_full | Fabric along the NEEM ice core, Greenland, and its comparison with GRIP and NGRIP ice cores |
| title_fullStr | Fabric along the NEEM ice core, Greenland, and its comparison with GRIP and NGRIP ice cores |
| title_full_unstemmed | Fabric along the NEEM ice core, Greenland, and its comparison with GRIP and NGRIP ice cores |
| title_short | Fabric along the NEEM ice core, Greenland, and its comparison with GRIP and NGRIP ice cores |
| title_sort | fabric along the neem ice core greenland and its comparison with grip and ngrip ice cores |
| url | http://www.the-cryosphere.net/8/1129/2014/tc-8-1129-2014.pdf |
| work_keys_str_mv | AT mmontagnat fabricalongtheneemicecoregreenlandanditscomparisonwithgripandngripicecores AT nazuma fabricalongtheneemicecoregreenlandanditscomparisonwithgripandngripicecores AT ddahljensen fabricalongtheneemicecoregreenlandanditscomparisonwithgripandngripicecores AT jeichler fabricalongtheneemicecoregreenlandanditscomparisonwithgripandngripicecores AT sfujita fabricalongtheneemicecoregreenlandanditscomparisonwithgripandngripicecores AT fgilletchaulet fabricalongtheneemicecoregreenlandanditscomparisonwithgripandngripicecores AT skipfstuhl fabricalongtheneemicecoregreenlandanditscomparisonwithgripandngripicecores AT dsamyn fabricalongtheneemicecoregreenlandanditscomparisonwithgripandngripicecores AT asvensson fabricalongtheneemicecoregreenlandanditscomparisonwithgripandngripicecores AT iweikusat fabricalongtheneemicecoregreenlandanditscomparisonwithgripandngripicecores |