Encyclopedia of Geomagnetism and Paleomagnetism

2007 Edition
| Editors: David Gubbins, Emilio Herrero-Bervera

Magnetization, Viscous Remanent (VRM)

  • David J. Dunlop
Reference work entry
DOI: https://doi.org/10.1007/978-1-4020-4423-6_200


Viscous magnetization is the gradual change of magnetization with time in an applied magnetic field H. Brief exposure of a ferromagnetic material to a field results in isothermal remanent magnetization (IRM). The additional remanence produced by a longer field exposure is viscous remanent magnetization (VRM). The longer the exposure time t, the stronger is the VRM.

Viscous remagnetization is the time‐dependent change of VRM or other remanences, such as thermoremanent magnetization (TRM), depositional remanent magnetization (DRM), or chemical remanent magnetization (CRM), in response to a change in the direction or strength of H. In nature, such field changes are due to secular variation, excursions, polarity transitions, or plate motion. In laboratory experiments, but never in nature, samples may be exposed to zero field and the viscous decay of their magnetization measured.

The natural remanent magnetization (NRM) of rocks, sediments, and soils usually includes a VRM...

This is a preview of subscription content, log in to check access.


  1. Biquand, D., and Prévot, M., 1971. AF demagnetization of viscous remanent magnetization in rocks. Zeitschrift für Geophysik, 37: 471–485.Google Scholar
  2. Borradaile, G.J., 2003. Viscous magnetization, archaeology and Bayesian statistics of small samples from Israel and England. Geophysical Research Letters, 30(10): 1528, doi:10.1029/2003GL016977.CrossRefGoogle Scholar
  3. Creer, K.M., 1957. The remanent magnetization of unstable Keuper marls. Philosophical Transactions of the Royal Society of London, A250: 130–143.CrossRefGoogle Scholar
  4. Dunlop, D.J., 1973. Theory of the magnetic viscosity of lunar and terrestrial rocks. Reviews of Geophysics and Space Physics, 11: 855–901.Google Scholar
  5. Dunlop, D.J., 1983. Viscous magnetization of 0.04–100 μm magnetites. Geophysical Journal of the Royal Astronomical Society, 74: 667–687.Google Scholar
  6. Dunlop, D.J., and Özdemir, Ö., 1990. Alternating field stability of high‐temperature viscous remanent magnetization. Physics of the Earth and Planetary Interiors, 65: 188–196.CrossRefGoogle Scholar
  7. Dunlop, D.J., and Özdemir, Ö., 1997. Rock Magnetism: Fundamentals and Frontiers. Cambridge: Cambridge University Press.Google Scholar
  8. Dunlop, D.J., and Özdemir, Ö., 2000. Effect of grain size and domain state on thermal demagnetization tails. Geophysical Research Letters, 27: 1311–1314.CrossRefGoogle Scholar
  9. Dunlop, D.J., Schmidt, P.W., Özdemir, Ö., and Clark, D.A., 1997. Paleomagnetism and paleothermometry of the Sydney Basin. 1. Thermoviscous and chemical overprinting of the Milton Monzonite. Journal of Geophysical Research, 102: 27 271–27 283.Google Scholar
  10. Dunlop, D.J., Özdemir, Ö., Clark, D.A., and Schmidt, P.W., 2000. Time‐temperature relations for the remagnetization of pyrrhotite (Fe7S8) and their use in estimating paleotemperatures. Earth and Planetary Science Letters, 176: 107–116.CrossRefGoogle Scholar
  11. Enkin, R.J., and Dunlop, D.J., 1988. The demagnetization temperature necessary to remove viscous remanent magnetization. Geophysical Research Letters, 15: 514–517.Google Scholar
  12. Fox, J.M.W., and Aitken, M.J., 1980. Cooling‐rate dependence of thermoremanent magnetisation. Nature, 283: 462–463.CrossRefGoogle Scholar
  13. Halgedahl, S.L., 1993. Experiments to investigate the origin of anomalously elevated unblocking temperatures. Journal of Geophysical Research, 98: 22 443–22 460.Google Scholar
  14. Heider, F., Halgdahl, S.L., and Dunlop, D.J., 1988. Temperature dependence of magnetic domains in magnetite crystals. Geophysical Research Letters, 15: 499–502.Google Scholar
  15. Heller, F., and Markert, H., 1973. The age of viscous remanent magnetization of Hadrian's Wall (northern England). Geophysical Journal of the Royal Astronomical Society, 31: 395–406.Google Scholar
  16. Jackson, M., and Worm, H.‐U., 2001. Anomalous unblocking temperatures, viscosity and frequency‐dependent susceptibility in the chemically‐remagnetized Trenton limestone. Physics of the Earth and Planetary Interiors, 126: 27–42.CrossRefGoogle Scholar
  17. Le Borgne, E., 1960. Étude expérimentale du traînage magnétique dans le cas d'un ensemble de grains magnétiques très fins dispersés dans une substance non magnétique. Annales de Géophysique, 16: 445–494.Google Scholar
  18. Lowrie, W., and Kent, D.V., 1978. Characteristics of VRM in oceanic basalts. Journal of Geophysics, 44: 297–315.Google Scholar
  19. Middleton, M.F., and Schmidt, P.W., 1982. Paleothermometry of the Sydney Basin. Journal of Geophysical Research, 87: 5351–5359.Google Scholar
  20. Moskowitz, B.M., 1985. Magnetic viscosity, diffusion after‐effect, and disaccommodation in natural and synthetic samples. Geophysical Journal of the Royal Astronomical Society, 82: 143–161.Google Scholar
  21. Mullins, C.E., and Tite, M.S., 1973. Magnetic viscosity, quadrature susceptibility, and frequency dependence of susceptibility in single‐domain assemblies of magnetite and maghemite. Journal of Geophysical Research, 78: 804–809.Google Scholar
  22. Néel, L., 1949. Théorie du traînage magnétique des ferromagnétiques en grain fins avec applications aux terres cuites. Annales de Géophysique, 5: 99–136.Google Scholar
  23. Néel, L., 1955. Some theoretical aspects of rock magnetism. Advances in Physics, 4: 191–243.CrossRefGoogle Scholar
  24. Perrin, M., 1998. Paleointensity determination, magnetic domain structure, and selection criteria. Journal of Geophysical Research, 103: 30 591–30 600.CrossRefGoogle Scholar
  25. Prévot, M., 1981. Some aspects of magnetic viscosity in subaerial and submarine volcanic rocks. Geophysical Journal of the Royal Astronomical Society, 66: 169–192.Google Scholar
  26. Pullaiah, G., Irving, E., Buchan, K.L., and Dunlop, D.J., 1975. Magnetization changes caused by burial and uplift. Earth and Planetary Science Letters, 28: 133–143.CrossRefGoogle Scholar
  27. Saito, T., Ishikawa, N., and Kamata, H., 2003. Identification of magnetic minerals carrying NRM in pyroclastic‐flow deposits. Journal of Volcanology and Geothermal Research, 126: 127–142.CrossRefGoogle Scholar
  28. Shimizu, Y., 1960. Magnetic viscosity of magnetite. Journal of Geomagnetism and Geoelectricity, 11: 125–138.Google Scholar
  29. Thellier, E., 1938. Sur l'aimantation des terres cuites et ses applications géophysiques. Annales de l'Institut de Physique Globe de l'Université de Paris, 16: 157–302Google Scholar
  30. Tivey, M., and Johnson, H.P., 1984. The characterization of viscous remanent magnetization in large and small magnetite particles. Journal of Geophysical Research, 89: 543–552.Google Scholar
  31. Walton, D., 1980. Time‐temperature relations in the magnetization of assemblies of single‐domain grains. Nature, 286: 245–247.CrossRefGoogle Scholar
  32. Walton, D., 1983. Viscous magnetization. Nature, 305: 616–619.CrossRefGoogle Scholar
  33. Walton, D., and Dunlop, D.J., 1985. The magnetization of a random assembly of interacting moments. Solid State Communications, 53: 359–362.CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • David J. Dunlop

There are no affiliations available