The periodic topography of ice stream beds: Insights from the Fourier spectra of mega-scale glacial lineations
Ice stream bed topography contains key evidence for the ways ice streams interact with, and are potentially controlled by, their beds. Here we present the first application of two-dimensional Fourier analysis to 22 marine and terrestrial topographies from 5 regions in Antarctica and Canada, with and...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/267028 2024-02-04T09:56:04+01:00 The periodic topography of ice stream beds: Insights from the Fourier spectra of mega-scale glacial lineations Spagnolo, M Bartholomaus, TC Clark, CD Stokes, CR Atkinson, N Dowdeswell, JA Ely, JC Graham, AGC Hogan, KA King, EC Larter, RD Livingstone, SJ Pritchard, HD 2017 application/pdf https://www.repository.cam.ac.uk/handle/1810/267028 https://doi.org/10.17863/CAM.12223 eng eng AGU Publications http://dx.doi.org/10.1002/2016jf004154 Journal of Geophysical Research: Earth Surface https://www.repository.cam.ac.uk/handle/1810/267028 doi:10.17863/CAM.12223 Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ ice stream bed mega-scale glacial lineations period topography pattern topography Fourier Article 2017 ftunivcam https://doi.org/10.17863/CAM.12223 2024-01-11T23:30:57Z Ice stream bed topography contains key evidence for the ways ice streams interact with, and are potentially controlled by, their beds. Here we present the first application of two-dimensional Fourier analysis to 22 marine and terrestrial topographies from 5 regions in Antarctica and Canada, with and without mega-scale glacial lineations (MSGLs). We find that the topography of MSGL-rich ice stream sedimentary beds is characterized by multiple, periodic wavelengths between 300 and 1200 m and amplitudes from decimeters to a few meters. This periodic topography is consistent with the idea that instability is a key element to the formation of MSGL bedforms. Dominant wavelengths vary among locations and, on one paleo ice stream bed, increase along the direction of ice flow by 1.7 ± 0.52% km−1. We suggest that these changes are likely to reflect pattern evolution via downstream wavelength coarsening, even under potentially steady ice stream geometry and flow conditions. The amplitude of MSGLs is smaller than that of other fluvial and glacial topographies but within the same order of magnitude. However, MSGLs are a striking component of ice stream beds because the topographic amplitude of features not aligned with ice flow is reduced by an order of magnitude relative to those oriented with the flow direction. This study represents the first attempt to automatically derive the spectral signatures of MSGLs. It highlights the plausibility of identifying these landform assemblages using automated techniques and provides a benchmark for numerical models of ice stream flow and subglacial landscape evolution. The research was funded by the NE/J004766/1 UK NERC New Investigator and a SAGES 728 PECRE grants awarded to MS. Article in Journal/Newspaper Antarc* Antarctica Apollo - University of Cambridge Repository Canada |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
ice stream bed mega-scale glacial lineations period topography pattern topography Fourier |
spellingShingle |
ice stream bed mega-scale glacial lineations period topography pattern topography Fourier Spagnolo, M Bartholomaus, TC Clark, CD Stokes, CR Atkinson, N Dowdeswell, JA Ely, JC Graham, AGC Hogan, KA King, EC Larter, RD Livingstone, SJ Pritchard, HD The periodic topography of ice stream beds: Insights from the Fourier spectra of mega-scale glacial lineations |
topic_facet |
ice stream bed mega-scale glacial lineations period topography pattern topography Fourier |
description |
Ice stream bed topography contains key evidence for the ways ice streams interact with, and are potentially controlled by, their beds. Here we present the first application of two-dimensional Fourier analysis to 22 marine and terrestrial topographies from 5 regions in Antarctica and Canada, with and without mega-scale glacial lineations (MSGLs). We find that the topography of MSGL-rich ice stream sedimentary beds is characterized by multiple, periodic wavelengths between 300 and 1200 m and amplitudes from decimeters to a few meters. This periodic topography is consistent with the idea that instability is a key element to the formation of MSGL bedforms. Dominant wavelengths vary among locations and, on one paleo ice stream bed, increase along the direction of ice flow by 1.7 ± 0.52% km−1. We suggest that these changes are likely to reflect pattern evolution via downstream wavelength coarsening, even under potentially steady ice stream geometry and flow conditions. The amplitude of MSGLs is smaller than that of other fluvial and glacial topographies but within the same order of magnitude. However, MSGLs are a striking component of ice stream beds because the topographic amplitude of features not aligned with ice flow is reduced by an order of magnitude relative to those oriented with the flow direction. This study represents the first attempt to automatically derive the spectral signatures of MSGLs. It highlights the plausibility of identifying these landform assemblages using automated techniques and provides a benchmark for numerical models of ice stream flow and subglacial landscape evolution. The research was funded by the NE/J004766/1 UK NERC New Investigator and a SAGES 728 PECRE grants awarded to MS. |
format |
Article in Journal/Newspaper |
author |
Spagnolo, M Bartholomaus, TC Clark, CD Stokes, CR Atkinson, N Dowdeswell, JA Ely, JC Graham, AGC Hogan, KA King, EC Larter, RD Livingstone, SJ Pritchard, HD |
author_facet |
Spagnolo, M Bartholomaus, TC Clark, CD Stokes, CR Atkinson, N Dowdeswell, JA Ely, JC Graham, AGC Hogan, KA King, EC Larter, RD Livingstone, SJ Pritchard, HD |
author_sort |
Spagnolo, M |
title |
The periodic topography of ice stream beds: Insights from the Fourier spectra of mega-scale glacial lineations |
title_short |
The periodic topography of ice stream beds: Insights from the Fourier spectra of mega-scale glacial lineations |
title_full |
The periodic topography of ice stream beds: Insights from the Fourier spectra of mega-scale glacial lineations |
title_fullStr |
The periodic topography of ice stream beds: Insights from the Fourier spectra of mega-scale glacial lineations |
title_full_unstemmed |
The periodic topography of ice stream beds: Insights from the Fourier spectra of mega-scale glacial lineations |
title_sort |
periodic topography of ice stream beds: insights from the fourier spectra of mega-scale glacial lineations |
publisher |
AGU Publications |
publishDate |
2017 |
url |
https://www.repository.cam.ac.uk/handle/1810/267028 https://doi.org/10.17863/CAM.12223 |
geographic |
Canada |
geographic_facet |
Canada |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/267028 doi:10.17863/CAM.12223 |
op_rights |
Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.17863/CAM.12223 |
_version_ |
1789960454114639872 |