Implications of a ductile crustal layer for the deformation caused by the Fennoscandian ice sheet
Previous studies of glacial–isostatic adjustment have usually considered earth models with a purely elastic lithosphere. A possibly significant deviation from this assumption is the presence of a ductile crustal layer embedded in an otherwise elastic lithosphere. Such a layer has been suggested for...
Published in: | Geophysical Journal International |
---|---|
Main Authors: | , |
Format: | Text |
Language: | English |
Published: |
Oxford University Press
1999
|
Subjects: | |
Online Access: | http://gji.oxfordjournals.org/cgi/content/short/139/1/216 https://doi.org/10.1046/j.1365-246X.1999.00936.x |
id |
fthighwire:oai:open-archive.highwire.org:gji:139/1/216 |
---|---|
record_format |
openpolar |
spelling |
fthighwire:oai:open-archive.highwire.org:gji:139/1/216 2023-05-15T16:12:51+02:00 Implications of a ductile crustal layer for the deformation caused by the Fennoscandian ice sheet Klemann, Volker Wolf, Detlef 1999-10-01 00:00:00.0 text/html http://gji.oxfordjournals.org/cgi/content/short/139/1/216 https://doi.org/10.1046/j.1365-246X.1999.00936.x en eng Oxford University Press http://gji.oxfordjournals.org/cgi/content/short/139/1/216 http://dx.doi.org/10.1046/j.1365-246X.1999.00936.x Copyright (C) 1999, Oxford University Press Articles TEXT 1999 fthighwire https://doi.org/10.1046/j.1365-246X.1999.00936.x 2015-02-28T21:23:33Z Previous studies of glacial–isostatic adjustment have usually considered earth models with a purely elastic lithosphere. A possibly significant deviation from this assumption is the presence of a ductile crustal layer embedded in an otherwise elastic lithosphere. Such a layer has been suggested for various continental regions on the basis of seismic and tectonic evidence. The present study investigates the implications of a ductile crustal layer for the interpretation of glacial–isostatic adjustment using a layered, incompressible Maxwell viscoelastic earth model and a simplified representation of the Fennoscandian glaciation. The relaxation-time and amplitude spectra show that, besides the conventional buoyancy mode M0 also present in earth models with a purely elastic lithosphere, the ductile layer supports a slowly decaying mode MC, which is capable of modifying the deformation markedly. Thus, measures of the absolute deformation such as the stress clearly reflect the presence of the ductile layer. In contrast to this are measures of the relative deformation such as the vertical displacement rate and the rate of gravity change. To a good approximation, these rates are inversely proportional to the relaxation time of the more quickly decaying mode M0, and are, therefore, less affected by the ductile layer. Taken together, the present study suggests that, provided a ductile crustal layer exists, its presence should be accounted for in interpretations of the glacial–isostatic adjustment following the Fennoscandian or smaller glaciations. Text Fennoscandian Ice Sheet HighWire Press (Stanford University) Geophysical Journal International 139 1 216 226 |
institution |
Open Polar |
collection |
HighWire Press (Stanford University) |
op_collection_id |
fthighwire |
language |
English |
topic |
Articles |
spellingShingle |
Articles Klemann, Volker Wolf, Detlef Implications of a ductile crustal layer for the deformation caused by the Fennoscandian ice sheet |
topic_facet |
Articles |
description |
Previous studies of glacial–isostatic adjustment have usually considered earth models with a purely elastic lithosphere. A possibly significant deviation from this assumption is the presence of a ductile crustal layer embedded in an otherwise elastic lithosphere. Such a layer has been suggested for various continental regions on the basis of seismic and tectonic evidence. The present study investigates the implications of a ductile crustal layer for the interpretation of glacial–isostatic adjustment using a layered, incompressible Maxwell viscoelastic earth model and a simplified representation of the Fennoscandian glaciation. The relaxation-time and amplitude spectra show that, besides the conventional buoyancy mode M0 also present in earth models with a purely elastic lithosphere, the ductile layer supports a slowly decaying mode MC, which is capable of modifying the deformation markedly. Thus, measures of the absolute deformation such as the stress clearly reflect the presence of the ductile layer. In contrast to this are measures of the relative deformation such as the vertical displacement rate and the rate of gravity change. To a good approximation, these rates are inversely proportional to the relaxation time of the more quickly decaying mode M0, and are, therefore, less affected by the ductile layer. Taken together, the present study suggests that, provided a ductile crustal layer exists, its presence should be accounted for in interpretations of the glacial–isostatic adjustment following the Fennoscandian or smaller glaciations. |
format |
Text |
author |
Klemann, Volker Wolf, Detlef |
author_facet |
Klemann, Volker Wolf, Detlef |
author_sort |
Klemann, Volker |
title |
Implications of a ductile crustal layer for the deformation caused by the Fennoscandian ice sheet |
title_short |
Implications of a ductile crustal layer for the deformation caused by the Fennoscandian ice sheet |
title_full |
Implications of a ductile crustal layer for the deformation caused by the Fennoscandian ice sheet |
title_fullStr |
Implications of a ductile crustal layer for the deformation caused by the Fennoscandian ice sheet |
title_full_unstemmed |
Implications of a ductile crustal layer for the deformation caused by the Fennoscandian ice sheet |
title_sort |
implications of a ductile crustal layer for the deformation caused by the fennoscandian ice sheet |
publisher |
Oxford University Press |
publishDate |
1999 |
url |
http://gji.oxfordjournals.org/cgi/content/short/139/1/216 https://doi.org/10.1046/j.1365-246X.1999.00936.x |
genre |
Fennoscandian Ice Sheet |
genre_facet |
Fennoscandian Ice Sheet |
op_relation |
http://gji.oxfordjournals.org/cgi/content/short/139/1/216 http://dx.doi.org/10.1046/j.1365-246X.1999.00936.x |
op_rights |
Copyright (C) 1999, Oxford University Press |
op_doi |
https://doi.org/10.1046/j.1365-246X.1999.00936.x |
container_title |
Geophysical Journal International |
container_volume |
139 |
container_issue |
1 |
container_start_page |
216 |
op_container_end_page |
226 |
_version_ |
1765998458406174720 |