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Secular Trends in Polar Motions: A New Tool for Probing the Viscosity of the Lower Mantle

Conference paper
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Part of the NATO Advanced Study Institutes Series book series (ASIC, volume 85)

Abstract

Transient flow in the mantle, induced by glacial cycles, produce small but discernible variations in the Earth’s rotational wobble and in the length of the day. These geophysical observables, which arise solely as a consequence of strain fields endowed with low order spherical harmonics (ℓ = 0 and ℓ = 2), can be usefel in distinguishing the viscosity structure of the lower mantle, potentially more so than inferences drawn from relative sea level and gravity anomaly data, whose spectral contents are dominated by much higher angular orders (ℓ ≳ 6). Results from dynamical calculations, which are constraint to fit both the speed of recent polar wander and the non-tidal acceleration of the Earth’s rotation rate, suggest that some amount of shrinkage of the Antarctic ice sheet since the late Wisconsin has occurred and that disintegration of Arctic marine ice sheets in the past may be a distinct possibility.

Keywords

Mantle viscosity ice ages polar wandering 

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References

  1. /1/.
    Cathles, L.M. III: 1975, The Viscosity of the Earth’s Mantle, Princeton Univ. Press.Google Scholar
  2. /2/.
    Peltier, W.R.: 1980, in Physics of the Earth’s Interior, ed. by A.M. Dziewonski and E. Boschi, North Holland Publ. Co., pp 362–431.Google Scholar
  3. /3/.
    Peltier, W.R.: 198l, Annu. Rev. Earth & Planet. Sci.9, pp 199–225.CrossRefGoogle Scholar
  4. /4/.
    Haskell, N.A.: 1937, Am. J. Sci. 33, pp 22–28.CrossRefGoogle Scholar
  5. /5/.
    Peltier, W.R. and Andrews, J.A.: 1976, Geophys. J.R. astr. Soc. 46, pp 605–646.CrossRefGoogle Scholar
  6. /6/.
    Wu, P. and Peltier, W.R.: 1981, Geophys. J.R. astr Soc., submitted.Google Scholar
  7. /7/.
    Takeuchi, H., Saito, M. and Kobayashi, N.: 1962, J.geophys. Res. 67, pp 1141–1154.ADSCrossRefGoogle Scholar
  8. /8/.
    Wu, P. and Peltier, W.R.: 1981, Geophys. J.R. astr. Soc., submitted.Google Scholar
  9. /9/.
    Dickman, S.R.: 1977, Geophys. J.R. astr. Soc. 51, PP 229–244.Google Scholar
  10. /10/.
    Soler, T. and Mueller, I.: 1978, Bull. Geodes. 52, pp 39–57.ADSCrossRefGoogle Scholar
  11. /11/.
    Nakibogly, S.M. and Lambeck, K.: 1980, Geophys. J.R. astr. Soc. 62, pp 49–58.Google Scholar
  12. /12/.
    Sabadini, R. and Peltier, W.R.: 198l, Geophys. J.R. astr. Soc. 66, in press.Google Scholar
  13. /13/.
    Morgan, W.J.: 1981, in The Sea, Vol. 7, ed. by C. Emiliani, J.C.Wiley, in press.Google Scholar
  14. /14/.
    Jurdy, D.M.: 1981, Tectonophys, 74, 1–17.CrossRefGoogle Scholar
  15. /15/.
    Sabadini, R., Yuen, D.A. and Boschi, E.: 1981, J. geophys. Res., in press.Google Scholar
  16. /16/.
    Sabadini, R. and Yuen, D.A.: 1982, in The Ninth International Symposium on Earth Tides, ed. by J. Kuo and P. Melchior, Schweizerbart-Verlag, Stuttgart, in press.Google Scholar
  17. /17/.
    Munk, W.H. and MacDonald, G.J.F.: 1960, The Rotation of the Earth, Cambridge Univ. P.Google Scholar
  18. /18/.
    Emiliani, C.: 1955, J. Geol. 63, pp 538–578.ADSCrossRefGoogle Scholar
  19. /19/.
    Hays, J.D.; Imbrie J. and Shackleton, N.J.: 1976, Science 194, PP 1121–1132.ADSCrossRefGoogle Scholar
  20. /20/.
    Sabadini, R., Yuen, D.A. and Boschi, E.: 1982 Nature, submitted.Google Scholar
  21. /21/.
    Milankovitch, M.: 1930, in Handbuch der Klimatologie, I, ed. by W. Koppen and R. Geiger, Gebruder Bornträger, pp 1–176.Google Scholar
  22. /22/.
    Lambeck, K.: 1979, in The Earth: Its Origin, Structure and Evolution, ed. by M.W. McElhinny, Academic Press, London, pp 59–81.Google Scholar
  23. /23/.
    Backus, G.E. and Gilbert, J.F.: 1967, Geophys, J.R. astr. Soc. 13, pp 247–276.ADSGoogle Scholar
  24. /24/.
    Peltier, W.R.: 1976, Geophys. J.R. astr. Soc. 46, pp 669–705.CrossRefGoogle Scholar
  25. /25/.
    Hughes, T.J., Denton, G.H., Andersen, B.G., Schilling, D.H., Fastook, G.L., and Lingle, C.S.: 1981, in The last Great Ice Sheets, ed. by G.H. Denton and T.J. Hughes, J.Wiley and Sons, pp 275–308.Google Scholar
  26. /26/.
    CLIMAP Project Members: 1976, Science 191, pp 1131–1137.ADSCrossRefGoogle Scholar
  27. /27/.
    Hughes, T.J., Denton, G.H. and Grosswald, M.G.: 1977, Nature 266, pp 596–602.ADSCrossRefGoogle Scholar
  28. /28/.
    Lingle, C.S. and Clark, J.A.: 1979, J.Glaciol. 24, pp 213–230.ADSGoogle Scholar

Copyright information

© D. Reidel Publishing Company 1982

Authors and Affiliations

  1. 1.Istituto di GeofisicaBologna. I.N.F.N.BolognaItaly
  2. 2.Dept. of GeologyArizona State UniversityTempeUSA

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