Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Evolutionary Processes and Reversals of the Earth's Magnetic Field


IT has been suggested that there is a connexion between reversals of the Earth's magnetic field and evolutionary processes1–3. This topic has excited much interest since the discovery of an apparent correlation between levels of field reversal and microfaunal discontinuities in deep sea sediment cores4. The Earth's magnetic field is known to have reversed its polarity at least nine times during the past 4 × 106 yr5,6 and at frequent intervals before that except during the Permian7. Briefly, the ideas of Uffen1,2 and Simpson3 are that during the process of a reversal there is a period of reduced or zero intensity of the dipole field during which there should be a great increase of cosmic radiation at the Earth, which is no longer shielded by its magnetic field. This enhanced radiation will produce a higher mutation rate, which will result in some kind of evolutionary discontinuity. There is good evidence that during the process of reversal, the Earth's dipole field is reduced in strength, probably passing through zdro4,8. The other assumptions are less acceptable.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout


  1. Uffen, R. J., Nature, 198, 143 (1963).

    Article  ADS  Google Scholar 

  2. Uffen, R. J., Proc. 22nd Intern. Geol. Cong., New Delhi (1964).

  3. Simpson, J. F., Bull. Geol. Soc. Amer., 77, 197 (1966).

    Article  ADS  Google Scholar 

  4. Opdyke, N. D., Glass, B., Hays, J. D., and Foster, J. H., Science, 154, 349 (1966).

    Article  ADS  CAS  Google Scholar 

  5. Doell, R. R., Dalrymple, G. B., and Cox, A., J. Geophys. Res., 71, 531 (1966).

    Article  ADS  Google Scholar 

  6. Doell, R. R., and Dalrymple, G. B., Science, 152, 1060 (1966).

    Article  ADS  CAS  Google Scholar 

  7. Irving, E., in Paleomagnetism (Wiley, 1965).

    Google Scholar 

  8. Harrison, C. G. A., and Somayajulu, B. L. K., Nature, 212, 1193 (1966).

    Article  ADS  Google Scholar 

  9. Rep. UN Sci. Com. Effects of Atomic Radiation, Gen. Ass., official records: seventeenth session, suppl. 16 (A/5216) (1962).

  10. Ginzburg, V. L., and Syrovatskii, S. I., in The Origin of Cosmic Rays (trans. by Massey, H. S. H., edit. by ter Haar, D.) (Macmillan Co., 1964).

    Book  Google Scholar 

  11. Compton, A. H., Phys. Rev., 43, 387 (1933).

    Article  ADS  Google Scholar 

  12. Lingenfelter, R. E., Rev. Geophys., 1, 35 (1963).

    Article  ADS  CAS  Google Scholar 

  13. Smith, P. J., Geophys. J. Roy. Astro. Soc., 12, 321 (1967).

    Article  ADS  Google Scholar 

  14. Bucha, V., Nature, 213, 1005 (1967).

    Article  ADS  Google Scholar 

  15. Kato, H., Schull, W. J., and Neel, J. V., J. Human Genet., 18, 339 (1966).

    CAS  Google Scholar 

  16. The Effects of Nuclear Weapons, rev. ed. (edit. by Glasstone, S.) (US AEC, 1964).

  17. Muller, H. J., Proc. Second UN Inter. Conf. Peaceful Uses of Atomic Energy, 22, 313 (1958).

    Google Scholar 

  18. Rubey, W. W., The Crust of the Earth, Geol. Soc. Amer. Spec. Paper, 62, 631 (1955).

    CAS  Google Scholar 

  19. King, J. W., and Kohl, H., Nature, 206, 699 (1965).

    Article  ADS  Google Scholar 

  20. King-Hele, D. G., and Allan, R. R., Roy. Air. Estab. Tech. Rep. 66212 (1966).

  21. Jacchia, J. G., and Slowey, J., in The Shape and Location of the Diurnal Bulge in the Upper Atmosphere (Smithsonian Institution, 1966).

    Google Scholar 

  22. Mitra, A. P., in Advances in Upper Atmosphere Research (edit. by Landmark, B.), 57 (Pergamon, 1963).

    Google Scholar 

Download references

Author information

Authors and Affiliations


Rights and permissions

Reprints and Permissions

About this article

Cite this article

HARRISON, C. Evolutionary Processes and Reversals of the Earth's Magnetic Field. Nature 217, 46–47 (1968).

Download citation

  • Received:

  • Revised:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing