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Deep Continental Roots: The Effects of Lateral Variations of Viscosity on Post-Glacial Rebound

  • P. Gasperini
  • R. Sabadini
  • D. A. Yuen
Chapter
Part of the NATO ASI Series book series (ASIC, volume 334)

Abstract

The existence of lateral viscosity variations in the earth mantle could be inferred by recent tomographic results. This can potentially cause substantial changes in the interpretation of the results from usual postglacial uplift modelling which assumes a uniform mantle. In this work we study the impact of a high viscosity craton located below the lithosphere in Fennoscandia. The solution is obtained using a finite element code which treats the surface rebound of an axisymmetrical viscoelastic half-space. The effects on the vertical displacements and velocity fields could be of the order of 30% in the centre of deglaciated areas and become larger for horizontal displacements, strain-fields and vertical velocities at the peripheral region. Viscosity increases beneath continental regions with respect to oceanic regions may be able to explain the systematically lower viscosity values inferred from sea-level data from Pacific Island sites. Our findings are potentially very important in the interpretation of GPS data.

Keywords

Gravity Anomaly Horizontal Displacement Maximum Shear Stress Global Position System Data Uniform Model 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Chapman D.S., 1985. Continental heat flow, in: Landolt-Bornstein Numerical Data and Functional Relationships in Science and Technology, New Series Vol. 2, edited by K. Fuchs and H. Soffel, Springer Verlag, pp 1–19.Google Scholar
  2. Dost B., 1990. Upper mantle structure under western Europe from fundamental and higher surface waves using the NARS array, Geophys. J. Int., 100, 131–151.CrossRefGoogle Scholar
  3. James T.S. and Morgan W.J., 1990. Horizontal motions due to post-glacial rebound, Geophys. Res. Lett., 17, 957–960.CrossRefGoogle Scholar
  4. Gasperini P. and Sabadini R., 1989. Lateral heterogeneities in mantle viscosity and post-glacial rebound, Geophys. J., 98, 413–428.CrossRefGoogle Scholar
  5. Gasperini P., Yuen D.A. and Sabadini R., 1990. Effects of viscosity variations on postglacial rebound: implications for recent sea-level trends, Geophys. Res. Lett., 17, 5–8.CrossRefGoogle Scholar
  6. Grand S.P., 1987. Tomographic inversion for shear velocity beneath the North-American plate, J. Geophys. Res., 92, 14065–14030.CrossRefGoogle Scholar
  7. Kroger P.M., Lyzenga G., Wallace K.S. and Davidson J.M., 1987. Tectonic motion in the western United States inferred from very long baseline interferometry measurements, 1980–1986, J. Geophys. Res., 92, 14151–14163.CrossRefGoogle Scholar
  8. Nakada M. and Lambeck K., 1991. Late Pleistocene and Holocene sea-level change; evidence for lateral mantle viscosity structure?, this volume.Google Scholar
  9. Sabadini R. and Gasperini P., 1989. Glacial isostasy and the interplay between upper and lower mantle lateral viscosity heterogeneities, Geophys. Res. Lett., 16, 429–432.CrossRefGoogle Scholar
  10. Sabadini R., Yuen D.A. and Portney M., 1986. The effects of upper-mantle lateral heterogeneities on post glacial rebound, Geophys. Res. Lett., 13, 337–340.CrossRefGoogle Scholar
  11. Tralli D.M. and Lichten S.M., 1990. Stochastic estimation of tropospheric path delays in Global Positioning System geodetic measurements, Bull. Gèod., 64, 127–159.CrossRefGoogle Scholar
  12. Woodhouse J. H. and Dziewonski A. M., 1984. Mapping the upper mantle: three-dimensional modeling of Earth structure by inversion of seismic waveforms, J. Geophys. Res., 89, 5953–5986.CrossRefGoogle Scholar
  13. Wolf D., 1984. The relaxation of spherical and flat Maxwell Earth models and effects due to presence of the lithosphere, J. Geophys, 56, 24–33Google Scholar
  14. Yan B., Graham E.K. and Furlong K.P., 1989. Lateral variations in upper mantle thermal structure inferred from three-dimensional seismic inversion models, Geophys. Res. Lett., 16, 449–452.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 1991

Authors and Affiliations

  • P. Gasperini
    • 1
  • R. Sabadini
    • 2
  • D. A. Yuen
    • 3
  1. 1.Istituto Nazionale di GeofisicaSezione di BolognaBolognaItaly
  2. 2.Dipartimento di Fisica - Settore GeofisicaUniversità di BolognaBolognaItaly
  3. 3.Minnesota Supercomputer InstituteUniversity of MinnesotaMinneapolisUSA

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