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What compensates the topography of southern Norway? Insights from thermo-isostatic modeling

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Title: What compensates the topography of southern Norway? Insights from thermo-isostatic modeling
Authors: Kolstrup, Marianne L.1 m.l.kolstrup@geo.uio.no, Pascal, Christophe2, Maupin, Valerie1
Source: Journal of Geodynamics. Oct2012, Vol. 61, p105-119. 15p.
Subjects: Mountains, Lithosphere, Surface waves (Fluids), Heat equation, Isostasy, Earth's mantle, Earth (Planet)
Geographic Terms: Baltic Shield, Norway
Abstract: Abstract: The origin of the high topography of the Norwegian Mountains is currently much debated. Several geophysical studies show that the uppermost mantle below southern Norway has anomalously low velocities as compared to other parts of the Baltic Shield. This study aims to shed lights on the structure of the lithospheric mantle below southern Norway by adapting and further refining a method based on isostatic and thermal equilibrium to compute temperature, temperature-related density and synthetic S-wave velocity in stable continental domains. The one-dimensional steady-state heat equation is used with topographic, Moho depth, crustal density and surface heat flow data. A condition of local isostasy is assumed and geoid undulations are used to constrain the range of possible lithosphere models. Results derived from this method suggest a thickening of the thermal lithosphere below southern Norway from west to east. The western part is found to have higher temperatures, lower densities and lower synthetic S-wave velocities than the eastern part, compatible with results from a recent P-wave travel time residual study. Comparison of the synthetic shear-velocity profiles beneath southwestern Norway with velocity profiles inverted from Rayleigh wave dispersion data suggests that the higher temperatures associated with a thinner lithosphere can explain parts of the seismic low-velocity anomaly. The inferred lithospheric structure is sensitive to uncertainties in the crustal input model, but the main features remain undisturbed by changes in the input data. The results show that the lithosphere of southwestern Norway can be in local isostatic equilibrium, if it is thinner and warmer than the lithosphere of eastern Norway. The present-day high topography may therefore be partially sustained by lower densities in the mantle lithosphere. [Copyright &y& Elsevier]
Copyright of Journal of Geodynamics is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
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Header DbId: egs
DbLabel: Engineering Source
An: 80221725
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
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  Data: What compensates the topography of southern Norway? Insights from thermo-isostatic modeling
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  Data: <searchLink fieldCode="AR" term="%22Kolstrup%2C+Marianne+L%2E%22">Kolstrup, Marianne L.</searchLink><relatesTo>1</relatesTo><i> m.l.kolstrup@geo.uio.no</i><br /><searchLink fieldCode="AR" term="%22Pascal%2C+Christophe%22">Pascal, Christophe</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Maupin%2C+Valerie%22">Maupin, Valerie</searchLink><relatesTo>1</relatesTo>
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  Data: <searchLink fieldCode="JN" term="%22Journal+of+Geodynamics%22">Journal of Geodynamics</searchLink>. Oct2012, Vol. 61, p105-119. 15p.
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  Data: <searchLink fieldCode="DE" term="%22Mountains%22">Mountains</searchLink><br /><searchLink fieldCode="DE" term="%22Lithosphere%22">Lithosphere</searchLink><br /><searchLink fieldCode="DE" term="%22Surface+waves+%28Fluids%29%22">Surface waves (Fluids)</searchLink><br /><searchLink fieldCode="DE" term="%22Heat+equation%22">Heat equation</searchLink><br /><searchLink fieldCode="DE" term="%22Isostasy%22">Isostasy</searchLink><br /><searchLink fieldCode="DE" term="%22Earth's+mantle%22">Earth's mantle</searchLink><br /><searchLink fieldCode="DE" term="%22Earth+%28Planet%29%22">Earth (Planet)</searchLink>
– Name: SubjectGeographic
  Label: Geographic Terms
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  Data: <searchLink fieldCode="DE" term="%22Baltic+Shield%22">Baltic Shield</searchLink><br /><searchLink fieldCode="DE" term="%22Norway%22">Norway</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Abstract: The origin of the high topography of the Norwegian Mountains is currently much debated. Several geophysical studies show that the uppermost mantle below southern Norway has anomalously low velocities as compared to other parts of the Baltic Shield. This study aims to shed lights on the structure of the lithospheric mantle below southern Norway by adapting and further refining a method based on isostatic and thermal equilibrium to compute temperature, temperature-related density and synthetic S-wave velocity in stable continental domains. The one-dimensional steady-state heat equation is used with topographic, Moho depth, crustal density and surface heat flow data. A condition of local isostasy is assumed and geoid undulations are used to constrain the range of possible lithosphere models. Results derived from this method suggest a thickening of the thermal lithosphere below southern Norway from west to east. The western part is found to have higher temperatures, lower densities and lower synthetic S-wave velocities than the eastern part, compatible with results from a recent P-wave travel time residual study. Comparison of the synthetic shear-velocity profiles beneath southwestern Norway with velocity profiles inverted from Rayleigh wave dispersion data suggests that the higher temperatures associated with a thinner lithosphere can explain parts of the seismic low-velocity anomaly. The inferred lithospheric structure is sensitive to uncertainties in the crustal input model, but the main features remain undisturbed by changes in the input data. The results show that the lithosphere of southwestern Norway can be in local isostatic equilibrium, if it is thinner and warmer than the lithosphere of eastern Norway. The present-day high topography may therefore be partially sustained by lower densities in the mantle lithosphere. [Copyright &y& Elsevier]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Journal of Geodynamics is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
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RecordInfo BibRecord:
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      – Type: doi
        Value: 10.1016/j.jog.2012.03.008
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      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 15
        StartPage: 105
    Subjects:
      – SubjectFull: Mountains
        Type: general
      – SubjectFull: Lithosphere
        Type: general
      – SubjectFull: Surface waves (Fluids)
        Type: general
      – SubjectFull: Heat equation
        Type: general
      – SubjectFull: Isostasy
        Type: general
      – SubjectFull: Earth's mantle
        Type: general
      – SubjectFull: Earth (Planet)
        Type: general
      – SubjectFull: Baltic Shield
        Type: general
      – SubjectFull: Norway
        Type: general
    Titles:
      – TitleFull: What compensates the topography of southern Norway? Insights from thermo-isostatic modeling
        Type: main
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          Name:
            NameFull: Kolstrup, Marianne L.
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            NameFull: Pascal, Christophe
      – PersonEntity:
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            NameFull: Maupin, Valerie
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          Dates:
            – D: 01
              M: 10
              Text: Oct2012
              Type: published
              Y: 2012
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              Value: 02643707
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              Value: 61
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            – TitleFull: Journal of Geodynamics
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