Ice stream motion facilitated by a shallow-deforming and accreting bed

Matteo Spagnolo; Emrys Phillips; Jan A. Piotrowski; Brice R. Rea; Chris D. Clark; Chris R. Stokes; Simon J. Carr; Jeremy C. Ely; Adriano Ribolini; Wojciech Wysota; Izabela Szuman

doi:10.1038/ncomms10723

Ice stream motion facilitated by a shallow-deforming and accreting bed

Matteo Spagnolo^*, Emrys Phillips, Jan A. Piotrowski, Brice R. Rea, Chris D. Clark, Chris R. Stokes, Simon J. Carr, Jeremy C. Ely, Adriano Ribolini, Wojciech Wysota, Izabela Szuman

^*Corresponding author for this work

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Abstract

Ice streams drain large portions of ice sheets and play a fundamental role in governing their response to atmospheric and oceanic forcing, with implications for sea-level change. The mechanisms that generate ice stream flow remain elusive. Basal sliding and/or bed deformation have been hypothesized, but ice stream beds are largely inaccessible. Here we present a comprehensive, multi-scale study of the internal structure of mega-scale glacial lineations (MSGLs) formed at the bed of a palaeo ice stream. Analyses were undertaken at macro-and microscales, using multiple techniques including X-ray tomography, thin sections and ground penetrating radar (GPR) acquisitions. Results reveal homogeneity in stratigraphy, kinematics, granulometry and petrography. The consistency of the physical and geological properties demonstrates a continuously accreting, shallow-deforming, bed and invariant basal conditions. This implies that ice stream basal motion on soft sediment beds during MSGL formation is accommodated by plastic deformation, facilitated by continuous sediment supply and an inefficient drainage system.

Original language	English
Article number	10723
Pages (from-to)	1-11
Number of pages	11
Journal	Nature Communications
Volume	7
DOIs	https://doi.org/10.1038/ncomms10723
Publication status	Published - 22 Feb 2016

Bibliographical note

The research was funded by the NE/J004766/1 UK NERC New Investigator grant awarded to M.S. and, in addition, by the Danish Agency for Science, Technology and Innovation grant 272-06-0450 to J.A.P. J.C.E. thanks the Denisons for funding his PhD. We thank Dr Adrian Palmer for the careful preparation of the thin sections; Dr Dmitri Mauquoy for assistance with the statistical analysis of the samples; Lucy Diggens for the CT scanning and volume reconstruction; the laboratory staff at the Department of Geoscience, Aarhus University, for the sedimentological analyses; and the cartographers at the School of Geosciences, University of Aberdeen, for the drawing of some of the figures.

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Ice stream motion facilitated by a shallow-deforming and accreting bed
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Cite this

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title = "Ice stream motion facilitated by a shallow-deforming and accreting bed",

abstract = "Ice streams drain large portions of ice sheets and play a fundamental role in governing their response to atmospheric and oceanic forcing, with implications for sea-level change. The mechanisms that generate ice stream flow remain elusive. Basal sliding and/or bed deformation have been hypothesized, but ice stream beds are largely inaccessible. Here we present a comprehensive, multi-scale study of the internal structure of mega-scale glacial lineations (MSGLs) formed at the bed of a palaeo ice stream. Analyses were undertaken at macro-and microscales, using multiple techniques including X-ray tomography, thin sections and ground penetrating radar (GPR) acquisitions. Results reveal homogeneity in stratigraphy, kinematics, granulometry and petrography. The consistency of the physical and geological properties demonstrates a continuously accreting, shallow-deforming, bed and invariant basal conditions. This implies that ice stream basal motion on soft sediment beds during MSGL formation is accommodated by plastic deformation, facilitated by continuous sediment supply and an inefficient drainage system.",

author = "Matteo Spagnolo and Emrys Phillips and Piotrowski, {Jan A.} and Rea, {Brice R.} and Clark, {Chris D.} and Stokes, {Chris R.} and Carr, {Simon J.} and Ely, {Jeremy C.} and Adriano Ribolini and Wojciech Wysota and Izabela Szuman",

note = "The research was funded by the NE/J004766/1 UK NERC New Investigator grant awarded to M.S. and, in addition, by the Danish Agency for Science, Technology and Innovation grant 272-06-0450 to J.A.P. J.C.E. thanks the Denisons for funding his PhD. We thank Dr Adrian Palmer for the careful preparation of the thin sections; Dr Dmitri Mauquoy for assistance with the statistical analysis of the samples; Lucy Diggens for the CT scanning and volume reconstruction; the laboratory staff at the Department of Geoscience, Aarhus University, for the sedimentological analyses; and the cartographers at the School of Geosciences, University of Aberdeen, for the drawing of some of the figures.",

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AU - Clark, Chris D.

AU - Stokes, Chris R.

AU - Carr, Simon J.

AU - Ely, Jeremy C.

AU - Ribolini, Adriano

AU - Wysota, Wojciech

AU - Szuman, Izabela

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PY - 2016/2/22

Y1 - 2016/2/22

N2 - Ice streams drain large portions of ice sheets and play a fundamental role in governing their response to atmospheric and oceanic forcing, with implications for sea-level change. The mechanisms that generate ice stream flow remain elusive. Basal sliding and/or bed deformation have been hypothesized, but ice stream beds are largely inaccessible. Here we present a comprehensive, multi-scale study of the internal structure of mega-scale glacial lineations (MSGLs) formed at the bed of a palaeo ice stream. Analyses were undertaken at macro-and microscales, using multiple techniques including X-ray tomography, thin sections and ground penetrating radar (GPR) acquisitions. Results reveal homogeneity in stratigraphy, kinematics, granulometry and petrography. The consistency of the physical and geological properties demonstrates a continuously accreting, shallow-deforming, bed and invariant basal conditions. This implies that ice stream basal motion on soft sediment beds during MSGL formation is accommodated by plastic deformation, facilitated by continuous sediment supply and an inefficient drainage system.

AB - Ice streams drain large portions of ice sheets and play a fundamental role in governing their response to atmospheric and oceanic forcing, with implications for sea-level change. The mechanisms that generate ice stream flow remain elusive. Basal sliding and/or bed deformation have been hypothesized, but ice stream beds are largely inaccessible. Here we present a comprehensive, multi-scale study of the internal structure of mega-scale glacial lineations (MSGLs) formed at the bed of a palaeo ice stream. Analyses were undertaken at macro-and microscales, using multiple techniques including X-ray tomography, thin sections and ground penetrating radar (GPR) acquisitions. Results reveal homogeneity in stratigraphy, kinematics, granulometry and petrography. The consistency of the physical and geological properties demonstrates a continuously accreting, shallow-deforming, bed and invariant basal conditions. This implies that ice stream basal motion on soft sediment beds during MSGL formation is accommodated by plastic deformation, facilitated by continuous sediment supply and an inefficient drainage system.

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Ice stream motion facilitated by a shallow-deforming and accreting bed

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Brice Rea

Matteo Spagnolo

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Ice stream motion facilitated by a shallow-deforming and accreting bed

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