Slip-band distributions and microstructural fading memory beneath the firn ice transition of polar ice sheets
The Antarctic Ice Sheet is a continental ice mass with circa 23 million gigatons of ice, which represent roughly 67 % of world's freshwater supply. This colossal mass of ice is by no means static, as the old ice slowly creeps under its own weight towards the ocean, while new ice is continually...
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ftunivpaisvasco:oai:addi.ehu.eus:10810/47614 2023-05-15T13:56:39+02:00 Slip-band distributions and microstructural fading memory beneath the firn ice transition of polar ice sheets Faria, S. H. 2018 application/pdf http://hdl.handle.net/10810/47614 eng eng Elsevier info:eu-repo/grantAgreement/MINECO/RYC-2012-12167 ES/6PN/RYC-2012-12167 https://dx.doi.org/10.1016/j.mechrescom.2018.09.009 Mechanics Research Communications 94 : 95-101 (2018) 0936413 http://hdl.handle.net/10810/47614 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-sa/3.0/es/ © 2018 Elsevier Ltd Atribución-NoComercial-CompartirIgual 3.0 España CC-BY-NC-SA Chains Creep Crystal microstructure Crystallization Dynamic recrystallization Glaciers Microstructure Polycrystalline materials Polycrystals Porous materials Recovery Residual stresses Sintering Snow Stabilization Strain energy Antarctica Firn Force chains Heterogeneous deformation Ice flow Slip band Ice info:eu-repo/semantics/article 2018 ftunivpaisvasco https://doi.org/10.1016/j.mechrescom.2018.09.009 2022-11-30T00:20:59Z The Antarctic Ice Sheet is a continental ice mass with circa 23 million gigatons of ice, which represent roughly 67 % of world's freshwater supply. This colossal mass of ice is by no means static, as the old ice slowly creeps under its own weight towards the ocean, while new ice is continually formed through the sintering of snow deposited on the ice sheet surface. A crucial role in this metamorphism is played by firn, which is the porous material in an intermediate state between the granular snow and the solid polycrystalline ice. Understanding the snow firn ice metamorphism is essential not only for a precise determination of the mechanical (creep) properties of polar ice, but also for comprehending the formation and decay of climate proxies widely used in ice-core studies. This work investigates the transition from firn to ice through the spatial and directional distributions of slip bands in bubbly ice. The analysis of high-resolution micrographs of ice sections extracted from the EPICA-DML Deep Ice Core allows us to identify a clear influence of strain-induced anisotropy (viz. c-axis preferred orientations) on the evolution of slip-band inclinations in deep bubbly ice. In contrast, we discover an unanticipated behaviour of slip bands in shallow bubbly ice, which prompts the introduction of the hypothesis of microstructural fading memory and the definition of a stabilization zone that may penetrate hundreds of metres into the bubbly ice. Within this stabilization zone, highly localized concentrations of strain energy and internal stresses once generated by force chains in the ancient firn are gradually redistributed by the newly formed bubbly-ice microstructure. We show that this hypothesis is compatible with the localized dynamic recrystallization episodes observed in polar firn (even at temperatures close to -45°C), and it may also explain the sluggish rotation of c-axes observed in the upper hundreds of metres of polar ice sheets. © 2018 Elsevier Ltd Financial support from the Ramón y Cajal grant ... Article in Journal/Newspaper Antarc* Antarctic Antarctica DML EPICA ice core Ice Sheet ADDI: Repositorio Institucional de la Universidad del País Vasco (UPV) Antarctic The Antarctic Mechanics Research Communications 94 95 101 |
institution |
Open Polar |
collection |
ADDI: Repositorio Institucional de la Universidad del País Vasco (UPV) |
op_collection_id |
ftunivpaisvasco |
language |
English |
topic |
Chains Creep Crystal microstructure Crystallization Dynamic recrystallization Glaciers Microstructure Polycrystalline materials Polycrystals Porous materials Recovery Residual stresses Sintering Snow Stabilization Strain energy Antarctica Firn Force chains Heterogeneous deformation Ice flow Slip band Ice |
spellingShingle |
Chains Creep Crystal microstructure Crystallization Dynamic recrystallization Glaciers Microstructure Polycrystalline materials Polycrystals Porous materials Recovery Residual stresses Sintering Snow Stabilization Strain energy Antarctica Firn Force chains Heterogeneous deformation Ice flow Slip band Ice Faria, S. H. Slip-band distributions and microstructural fading memory beneath the firn ice transition of polar ice sheets |
topic_facet |
Chains Creep Crystal microstructure Crystallization Dynamic recrystallization Glaciers Microstructure Polycrystalline materials Polycrystals Porous materials Recovery Residual stresses Sintering Snow Stabilization Strain energy Antarctica Firn Force chains Heterogeneous deformation Ice flow Slip band Ice |
description |
The Antarctic Ice Sheet is a continental ice mass with circa 23 million gigatons of ice, which represent roughly 67 % of world's freshwater supply. This colossal mass of ice is by no means static, as the old ice slowly creeps under its own weight towards the ocean, while new ice is continually formed through the sintering of snow deposited on the ice sheet surface. A crucial role in this metamorphism is played by firn, which is the porous material in an intermediate state between the granular snow and the solid polycrystalline ice. Understanding the snow firn ice metamorphism is essential not only for a precise determination of the mechanical (creep) properties of polar ice, but also for comprehending the formation and decay of climate proxies widely used in ice-core studies. This work investigates the transition from firn to ice through the spatial and directional distributions of slip bands in bubbly ice. The analysis of high-resolution micrographs of ice sections extracted from the EPICA-DML Deep Ice Core allows us to identify a clear influence of strain-induced anisotropy (viz. c-axis preferred orientations) on the evolution of slip-band inclinations in deep bubbly ice. In contrast, we discover an unanticipated behaviour of slip bands in shallow bubbly ice, which prompts the introduction of the hypothesis of microstructural fading memory and the definition of a stabilization zone that may penetrate hundreds of metres into the bubbly ice. Within this stabilization zone, highly localized concentrations of strain energy and internal stresses once generated by force chains in the ancient firn are gradually redistributed by the newly formed bubbly-ice microstructure. We show that this hypothesis is compatible with the localized dynamic recrystallization episodes observed in polar firn (even at temperatures close to -45°C), and it may also explain the sluggish rotation of c-axes observed in the upper hundreds of metres of polar ice sheets. © 2018 Elsevier Ltd Financial support from the Ramón y Cajal grant ... |
format |
Article in Journal/Newspaper |
author |
Faria, S. H. |
author_facet |
Faria, S. H. |
author_sort |
Faria, S. H. |
title |
Slip-band distributions and microstructural fading memory beneath the firn ice transition of polar ice sheets |
title_short |
Slip-band distributions and microstructural fading memory beneath the firn ice transition of polar ice sheets |
title_full |
Slip-band distributions and microstructural fading memory beneath the firn ice transition of polar ice sheets |
title_fullStr |
Slip-band distributions and microstructural fading memory beneath the firn ice transition of polar ice sheets |
title_full_unstemmed |
Slip-band distributions and microstructural fading memory beneath the firn ice transition of polar ice sheets |
title_sort |
slip-band distributions and microstructural fading memory beneath the firn ice transition of polar ice sheets |
publisher |
Elsevier |
publishDate |
2018 |
url |
http://hdl.handle.net/10810/47614 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Antarctica DML EPICA ice core Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica DML EPICA ice core Ice Sheet |
op_relation |
info:eu-repo/grantAgreement/MINECO/RYC-2012-12167 ES/6PN/RYC-2012-12167 https://dx.doi.org/10.1016/j.mechrescom.2018.09.009 Mechanics Research Communications 94 : 95-101 (2018) 0936413 http://hdl.handle.net/10810/47614 |
op_rights |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-sa/3.0/es/ © 2018 Elsevier Ltd Atribución-NoComercial-CompartirIgual 3.0 España |
op_rightsnorm |
CC-BY-NC-SA |
op_doi |
https://doi.org/10.1016/j.mechrescom.2018.09.009 |
container_title |
Mechanics Research Communications |
container_volume |
94 |
container_start_page |
95 |
op_container_end_page |
101 |
_version_ |
1766264181776973824 |