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.

Dependence of the duration of geomagnetic polarity reversals on site latitude


An important constraint on the processes governing the geodynamo—the flow in the outer core responsible for generating Earth's magnetic field—is the duration of geomagnetic polarity reversals; that is, how long it takes for Earth's magnetic field to reverse1. It is generally accepted that Earth's magnetic field strength drops to low levels during polarity reversals, and the field direction progresses through a 180° change while the field is weak1. The time it takes for this process to happen, however, remains uncertain, with estimates ranging from a few thousand up to 28,000 years. Here I present an analysis of the available sediment records of the four most recent polarity reversals. These records yield an average estimate of about 7,000 years for the time it takes for the directional change to occur. The variation about this mean duration is not random, but instead varies with site latitude, with shorter durations observed at low-latitude sites, and longer durations observed at mid- to high-latitude sites. Such variation of duration with site latitude is predicted by simple geometrical reversal models, in which non-dipole fields are allowed to persist while the axial dipole decays through zero and then builds in the opposite direction, and provides a constraint on numerical dynamo models.

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

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Comparison of the transition-zone thickness in the lower Jaramillo record from ODP Hole 758A (ref.
Figure 2: The duration of the directional changes during polarity transitions varies as a function of site latitude.
Figure 3: The durations do not correlate with sedimentation rates.
Figure 4: Simple geometrical models in which standing non-dipole fields are allowed to persist while the axial dipole field decays to zero and then builds up in the opposite direction produce transition durations that vary systematically with latitude.


  1. Merrill, R. T. & McFadden, P. L. Geomagnetic polarity transitions. Rev. Geophys. 37, 201–226 (1999)

    Article  ADS  Google Scholar 

  2. Singer, B. S. & Pringle, M. S. Age and duration of the Matuyama-Brunhes geomagnetic polarity reversal from 40Ar/39Ar incremental heating analyses of lavas. Earth Planet. Sci. Lett. 139, 47–61 (1996)

    Article  ADS  CAS  Google Scholar 

  3. McElhinny, M. W. & Lock, J. IAGA paleomagnetic databases with access. Surv. Geophys. 17, 575–591 (1996)

    Article  ADS  Google Scholar 

  4. Channell, J. E. T. & Lehman, B. The last two geomagnetic polarity reversals recorded in high-deposition-rate sediment drifts. Nature 389, 712–715 (1997)

    Article  ADS  CAS  Google Scholar 

  5. Yamazaki, T. & Oda, H. Orbital influence on Earth's magnetic field; 100,000-year periodicity in inclination. Science 295, 2435–2438 (2002)

    Article  ADS  CAS  Google Scholar 

  6. Oda, H., Shibuya, H. & Hsu, V. Palaeomagnetic records of the Brunhes/Matuyama polarity transition from ODP Leg 124 (Celebes and Sulu seas). Geophys. J. Int. 142, 319–338 (2000)

    Article  ADS  Google Scholar 

  7. Fisher, R. A. Dispersion on a sphere. Proc. R. Astron. Soc. A 217, 295–305 (1953)

    Article  ADS  MathSciNet  Google Scholar 

  8. Channell, J. E. T., Hodell, D. A. & Lehman, B. Relative geomagnetic paleointensity and δ18O at ODP Site 983 (Gardar Drift, North Atlantic) since 350 ka. Earth Planet. Sci. Lett. 153, 103–118 (1997)

    Article  ADS  CAS  Google Scholar 

  9. Cande, S. C. & Kent, D. V. Revised calibration of the geomagnetic polarity time scale for the Late Cretacous and Cenozoic. J. Geophys. Res. 100, 6093–6095 (1995)

    Article  ADS  Google Scholar 

  10. Holt, J. W. & Kirschvink, J. L. The upper Olduvai geomagnetic field reversal from Death Valley, California; a fold test of transitional directions. Earth Planet. Sci. Lett. 133, 475–491 (1995)

    Article  ADS  CAS  Google Scholar 

  11. Clement, B. M. & Kent, D. V. Latitudinal dependency of geomagnetic polarity transition durations. Nature 310, 488–491 (1984)

    Article  ADS  Google Scholar 

  12. Dormy, E., Valet, J.-P. & Courtillot, V. Numerical models of the geodynamo and observational constraints. Geochem. Geophys. Geosyst. 1, doi:2000GC000062 (2000)

  13. McMillan, D. G., Constable, C. G., Parker, R. L. & Glatzmaier, G. A. A statistical analysis of magnetic fields from some geodynamo simulations. Geochem. Geophys. Geosyst.[online] 28, doi:2000GC000130 (2001)

  14. Coe, R. S., Hongre, L. & Glatzmaier, G. A. An examination of simulated geomagnetic reversals from a palaeomagnetic perspective. Phil. Trans. R. Soc. 358, 1141–1170 (2000)

    Article  ADS  Google Scholar 

  15. Clement, B. M. & Kent, D. V. A southern hemisphere record of the Matuyama-Brunhes polarity reversal. Geophys. Res. Lett. 18, 81–84 (1991)

    Article  ADS  Google Scholar 

  16. Theyer, F., Herrero-Bervera, E., Hsu, V. & Hammond, S. R. The zonal harmonic model of polarity transitions; a test using successive reversals. J. Geophys. Res. B 90, 1963–1982 (1985)

    Article  ADS  Google Scholar 

  17. Valet, J.-P., Tauxe, L. & Clement, B. Equatorial and mid-latitude records of the last geomagnetic reversal from the Atlantic Ocean. Earth Planet. Sci. Lett. 94, 371–384 (1989)

    Article  ADS  Google Scholar 

  18. Clement, B. M., Kent, D. V. & Opdyke, N. D. Brunhes-Matuyama polarity transition in three deep-sea sediment cores. Phil. Trans. R. Soc. Lond. 306, 113–119 (1982)

    Article  ADS  Google Scholar 

  19. Cisowski, S. M. et al. Detailed record of the Brunhes/Matuyama polarity reversal in high sedimentation rate marine sediments from the Isu-Bonin Arc. Proc. ODP Sci. Res. 126, 341–352 (1992)

    Google Scholar 

  20. Zhu, R., Laj, C. & Mazuad, A. The Matuyama-Brunhes and upper Jaramillo transitions recorded in a loess section at Weinan, north-central China. Earth Planet. Sci. Lett. 125, 143–158 (1994)

    Article  ADS  Google Scholar 

  21. Okada, M. & Niitsuma, N. Detailed paleomagnetic records during the Brunhes-Matuyama geomagnetic reversal, and a direct determination of depth lag for magnetization in marine sediments. Phys. Earth Planet. Inter. 56, 133–150 (1989)

    Article  ADS  Google Scholar 

  22. Valet, J.-P., Tauxe, L. & Clark, C. R. The Brunhes-Matuyama transition recorded from Lake Tecopa sediments (California). Earth Planet. Sci. Lett. 87, 463–472 (1988)

    Article  ADS  CAS  Google Scholar 

  23. Clement, B. M., Kent, D. V. Geomagnetic polarity transition records from five hydraulic piston core sites in the North Atlantic. in Init. Rep. Deep Sea Drilling Project (ed. Ruddiman, W. F. et al.) 94, 831–852 (US Government Printing Office, Washington, 1987)

    Google Scholar 

  24. Athanossopolous, J. A Matuyama-Brunhes Polarity Reversal Record; Comparison Between Thermal and Alternating Field Demagnetization of Ocean Sediments from the North Pacific Transect. PhD thesis, Univ. California, Santa Barbara, 225 (1993)

    Google Scholar 

  25. Herrero-Bervera, E. & Theyer, F. Non-axisymmetric behaviour of Olduvai and Jaramillo polarity transitions recorded in north-central Pacific deep-sea sediments. Nature 322, 159–162 (1986)

    Article  ADS  Google Scholar 

  26. Clement, B. M. & Kent, D. V. A detailed record of the lower Jaramillo polarity transition from a southern hemisphere, deep-sea sediment core. J. Geophys. Res. 89, 1049–1058 (1984)

    Article  ADS  Google Scholar 

  27. Gee, J. S. et al. Lower Jaramillo polarity transition records from the equatorial Atlantic and Indian oceans. Proc. ODP Sci. Res. 121, 377–391 (1991)

    Google Scholar 

  28. Clement, B. M. & Kent, D. V. A comparison of two sequential geomagnetic polarity transitions (upper Olduvai and lower Jaramillo) from the Southern Hemisphere. Phys. Earth Planet. Inter. 39, 301–313 (1985)

    Article  ADS  Google Scholar 

  29. Herrero-Bervera, E. & Khan, M. A. Olduvai termination; detailed palaeomagnetic analysis of a north central Pacific core. Geophys. J. Int. 108, 535–545 (1992)

    Article  ADS  Google Scholar 

Download references


R. Coe, D. V. Kent, J. Dauphin & B. Midson provided comments that improved the manuscript. J. E. T. Channell and T. Yamazaki provided their data for this work.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Bradford M. Clement.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Clement, B. Dependence of the duration of geomagnetic polarity reversals on site latitude. Nature 428, 637–640 (2004).

Download citation

  • Received:

  • Accepted:

  • 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