The impact of lateral variations in lithospheric thickness on glacial isostatic adjustment in West Antarctica.
Differences in predictions of Glacial Isostatic Adjustment (GIA) for Antarctica persist due to uncertainties in deglacial history and Earth rheology. The Earth models adopted in many GIA studies are defined by parameters that vary in the radial direction only and represent a global average Earth str...
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Oxford University Press
2018
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Online Access: | http://dro.dur.ac.uk/24696/ http://dro.dur.ac.uk/24696/1/24696.pdf http://dro.dur.ac.uk/24696/2/24696.pdf https://doi.org/10.1093/gji/ggy158 |
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ftunivdurham:oai:dro.dur.ac.uk.OAI2:24696 2023-05-15T13:47:56+02:00 The impact of lateral variations in lithospheric thickness on glacial isostatic adjustment in West Antarctica. Nield, G.A. Whitehouse, P.L. van der Wal, W. Blank, B. O'Donnell, J.P. Stuart, G.W. 2018-08-01 application/pdf http://dro.dur.ac.uk/24696/ http://dro.dur.ac.uk/24696/1/24696.pdf http://dro.dur.ac.uk/24696/2/24696.pdf https://doi.org/10.1093/gji/ggy158 unknown Oxford University Press dro:24696 issn:0956-540X issn: 1365-246X doi:10.1093/gji/ggy158 http://dro.dur.ac.uk/24696/ https://doi.org/10.1093/gji/ggy158 http://dro.dur.ac.uk/24696/1/24696.pdf http://dro.dur.ac.uk/24696/2/24696.pdf © The Author(s) 2018. Published by Oxford University Press on behalf of The Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. CC-BY Geophysical journal international, 2018, Vol.214(2), pp.811-824 [Peer Reviewed Journal] Article PeerReviewed 2018 ftunivdurham https://doi.org/10.1093/gji/ggy158 2020-05-28T22:39:43Z Differences in predictions of Glacial Isostatic Adjustment (GIA) for Antarctica persist due to uncertainties in deglacial history and Earth rheology. The Earth models adopted in many GIA studies are defined by parameters that vary in the radial direction only and represent a global average Earth structure (referred to as 1D Earth models). Over-simplifying actual Earth structure leads to bias in model predictions in regions where Earth parameters differ significantly from the global average, such as West Antarctica. We investigate the impact of lateral variations in lithospheric thickness on GIA in Antarctica by carrying out two experiments that use different rheological approaches to define 3D Earth models that include spatial variations in lithospheric thickness. The first experiment defines an elastic lithosphere with spatial variations in thickness inferred from seismic studies. We compare the results from this 3D model with results derived from a 1D Earth model that has a uniform lithospheric thickness defined as the average of the 3D lithospheric thickness. Irrespective of deglacial history and sub-lithospheric mantle viscosity, we find higher gradients of present-day uplift rates (i.e. higher amplitude and shorter wavelength) in West Antarctica when using the 3D models, due to the thinner-than-1D-average lithosphere prevalent in this region. The second experiment uses seismically-inferred temperature as input to a power-law rheology thereby allowing the lithosphere to have a viscosity structure. Modelling the lithosphere with a power-law rheology results in behaviour that is equivalent to a thinner-lithosphere model, and it leads to higher amplitude and shorter wavelength deformation compared with the first experiment. We conclude that neglecting spatial variations in lithospheric thickness in GIA models will result in predictions of peak uplift and subsidence that are biased low in West Antarctica. This has important implications for ice-sheet modelling studies as the steeper gradients of uplift predicted from the more realistic 3D model may promote stability in marine-grounded regions of West Antarctica. Including lateral variations in lithospheric thickness, at least to the level of considering West and East Antarctica separately, is important for capturing short wavelength deformation and it has the potential to provide a better fit to GPS observations as well as an improved GIA correction for GRACE data. Article in Journal/Newspaper Antarc* Antarctica East Antarctica Ice Sheet West Antarctica Durham University: Durham Research Online East Antarctica West Antarctica Geophysical Journal International 214 2 811 824 |
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Open Polar |
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Durham University: Durham Research Online |
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ftunivdurham |
language |
unknown |
description |
Differences in predictions of Glacial Isostatic Adjustment (GIA) for Antarctica persist due to uncertainties in deglacial history and Earth rheology. The Earth models adopted in many GIA studies are defined by parameters that vary in the radial direction only and represent a global average Earth structure (referred to as 1D Earth models). Over-simplifying actual Earth structure leads to bias in model predictions in regions where Earth parameters differ significantly from the global average, such as West Antarctica. We investigate the impact of lateral variations in lithospheric thickness on GIA in Antarctica by carrying out two experiments that use different rheological approaches to define 3D Earth models that include spatial variations in lithospheric thickness. The first experiment defines an elastic lithosphere with spatial variations in thickness inferred from seismic studies. We compare the results from this 3D model with results derived from a 1D Earth model that has a uniform lithospheric thickness defined as the average of the 3D lithospheric thickness. Irrespective of deglacial history and sub-lithospheric mantle viscosity, we find higher gradients of present-day uplift rates (i.e. higher amplitude and shorter wavelength) in West Antarctica when using the 3D models, due to the thinner-than-1D-average lithosphere prevalent in this region. The second experiment uses seismically-inferred temperature as input to a power-law rheology thereby allowing the lithosphere to have a viscosity structure. Modelling the lithosphere with a power-law rheology results in behaviour that is equivalent to a thinner-lithosphere model, and it leads to higher amplitude and shorter wavelength deformation compared with the first experiment. We conclude that neglecting spatial variations in lithospheric thickness in GIA models will result in predictions of peak uplift and subsidence that are biased low in West Antarctica. This has important implications for ice-sheet modelling studies as the steeper gradients of uplift predicted from the more realistic 3D model may promote stability in marine-grounded regions of West Antarctica. Including lateral variations in lithospheric thickness, at least to the level of considering West and East Antarctica separately, is important for capturing short wavelength deformation and it has the potential to provide a better fit to GPS observations as well as an improved GIA correction for GRACE data. |
format |
Article in Journal/Newspaper |
author |
Nield, G.A. Whitehouse, P.L. van der Wal, W. Blank, B. O'Donnell, J.P. Stuart, G.W. |
spellingShingle |
Nield, G.A. Whitehouse, P.L. van der Wal, W. Blank, B. O'Donnell, J.P. Stuart, G.W. The impact of lateral variations in lithospheric thickness on glacial isostatic adjustment in West Antarctica. |
author_facet |
Nield, G.A. Whitehouse, P.L. van der Wal, W. Blank, B. O'Donnell, J.P. Stuart, G.W. |
author_sort |
Nield, G.A. |
title |
The impact of lateral variations in lithospheric thickness on glacial isostatic adjustment in West Antarctica. |
title_short |
The impact of lateral variations in lithospheric thickness on glacial isostatic adjustment in West Antarctica. |
title_full |
The impact of lateral variations in lithospheric thickness on glacial isostatic adjustment in West Antarctica. |
title_fullStr |
The impact of lateral variations in lithospheric thickness on glacial isostatic adjustment in West Antarctica. |
title_full_unstemmed |
The impact of lateral variations in lithospheric thickness on glacial isostatic adjustment in West Antarctica. |
title_sort |
impact of lateral variations in lithospheric thickness on glacial isostatic adjustment in west antarctica. |
publisher |
Oxford University Press |
publishDate |
2018 |
url |
http://dro.dur.ac.uk/24696/ http://dro.dur.ac.uk/24696/1/24696.pdf http://dro.dur.ac.uk/24696/2/24696.pdf https://doi.org/10.1093/gji/ggy158 |
geographic |
East Antarctica West Antarctica |
geographic_facet |
East Antarctica West Antarctica |
genre |
Antarc* Antarctica East Antarctica Ice Sheet West Antarctica |
genre_facet |
Antarc* Antarctica East Antarctica Ice Sheet West Antarctica |
op_source |
Geophysical journal international, 2018, Vol.214(2), pp.811-824 [Peer Reviewed Journal] |
op_relation |
dro:24696 issn:0956-540X issn: 1365-246X doi:10.1093/gji/ggy158 http://dro.dur.ac.uk/24696/ https://doi.org/10.1093/gji/ggy158 http://dro.dur.ac.uk/24696/1/24696.pdf http://dro.dur.ac.uk/24696/2/24696.pdf |
op_rights |
© The Author(s) 2018. Published by Oxford University Press on behalf of The Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1093/gji/ggy158 |
container_title |
Geophysical Journal International |
container_volume |
214 |
container_issue |
2 |
container_start_page |
811 |
op_container_end_page |
824 |
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1766248017279582208 |