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.

  • Letter
  • Published:

Structural and temporal requirements for geomagnetic field reversal deduced from lava flows


Reversals of the Earth's magnetic field reflect changes in the geodynamo—flow within the outer core—that generates the field. Constraining core processes or mantle properties that induce or modulate reversals requires knowing the timing and morphology of field changes that precede and accompany these reversals1,2,3,4. But the short duration of transitional field states and fragmentary nature of even the best palaeomagnetic records make it difficult to provide a timeline for the reversal process1,5. 40Ar/39Ar dating of lavas on Tahiti, long thought to record the primary part of the most recent ‘Matuyama–Brunhes’ reversal, gives an age of 795 ± 7 kyr, indistinguishable from that of lavas in Chile and La Palma that record a transition in the Earth's magnetic field, but older than the accepted age for the reversal. Only the ‘transitional’ lavas on Maui and one from La Palma (dated at 776 ± 2 kyr), agree with the astronomical age for the reversal. Here we propose that the older lavas record the onset of a geodynamo process, which only on occasion would result in polarity change. This initial instability, associated with the first of two decreases in field intensity, began 18 kyr before the actual polarity switch. These data support the claim6 that complete reversals require a significant period for magnetic flux to escape from the solid inner core and sufficiently weaken its stabilizing effect7.

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

Access options

Buy this article

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

Figure 1: 40Ar/39Ar age spectra and isochrons from lavas TT, RIT and RIV in Punaruu Valley, Tahiti.
Figure 2: Virtual Geomagnetic Poles (VGPs) and paths of four lava sequences that record transitional directions between 795 and 775 kyr ago.
Figure 3: 40Ar/39Ar ages of 23 transitionally magnetized lava flows and palaeointensity records from 12 marine cores25.

Similar content being viewed by others


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

    Article  ADS  Google Scholar 

  2. Laj, C., Mazaud, A., Weeks, R., Fuller, M. & Herrero-Bervera, E. Geomagnetic reversal paths. Nature 351, 447 (1991)

    Article  ADS  Google Scholar 

  3. Glatzmaier, G. A., Coe, R. S., Hongre, L. & Roberts, P. H. The role of the Earth's mantle in controlling the frequency of geomagnetic reversals. Nature 401, 885–890 (1999)

    Article  ADS  Google Scholar 

  4. Hoffman, K. A. Dipolar reversal states of the geomagnetic field and core-mantle dynamics. Nature 359, 789–794 (1992)

    Article  ADS  Google Scholar 

  5. Coe, R. S. & Glen, J. M. G. The complexity of reversals. In Timescales of the Paleomagnetic Field (eds Channell, J. E. T., Kent, D. V., Lowrie, W. & Meert, J.) 221–232 (Am. Geophys. Un. Geophys. Monogr. 145, 2004)

    Google Scholar 

  6. Gubbins, D. The distinction between geomagnetic excursions and reversals. Geophys. J. Int. 137, F1–F3 (1999)

    Article  Google Scholar 

  7. Hollerbach, R. & Jones, C. A. Influence of the Earth's inner core on geomagnetic fluctuations and reversals. Nature 365, 541–543 (1993)

    Article  ADS  Google Scholar 

  8. Laj, C., Guitton, S. & Kissel, C. Rapid changes and near-stationarity of the geomagnetic field during a polarity reversal. Nature 330, 145–148 (1987)

    Article  ADS  Google Scholar 

  9. 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 

  10. Kent, D. V. & Schneider, D. A. Correlation of paleointensity variation records in the Brunhes-Matuyama polarity transition interval. Earth Planet. Sci. Lett. 129, 135–144 (1995)

    Article  ADS  CAS  Google Scholar 

  11. Channell, J. E. T. & Kleiven, H. F. Geomagnetic palaeointensities and astrochronologic ages for the Matuyama-Brunhes boundary and the boundaries of the Jaramillo Subchron: palaeomagnetic and oxygen isotope records from ODP site 983. Phil. Trans. R. Soc. Lond. A 358, 1027–1047 (2000)

    Article  ADS  CAS  Google Scholar 

  12. Shackleton, N. J., Berger, A. & Peltier, W. R. An alternative astronomical calibration of the lower Pleistocene timescale based on ODP site 677. Trans. R. Soc. Edinb. Earth Sci. 81, 251–261 (1990)

    Article  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  14. Hoffman, K. A. Transitional field behavior from southern hemisphere lavas: evidence for two-stage reversals of the geodynamo. Nature 320, 228–232 (1986)

    Article  ADS  Google Scholar 

  15. Singer, B. S., Hoffman, K. A., Chauvin, A., Coe, R. S. & Pringle, M. S. Dating transitionally magnetized lavas of the late Matuyama Chron: Toward a new 40Ar/39Ar timescale of reversals and events. J. Geophys. Res. 104, 679–693 (1999)

    Article  ADS  Google Scholar 

  16. Singer, B. S. et al. Ar/Ar ages of transitionally magnetized lavas on La Palma, Canary Islands, and the Geomagnetic Instability Timescale. J. Geophys. Res. Solid Earth 107(B11), doi:10.1029/2001JB001613 (2002)

  17. Coe, R. S., Singer, B. S., Pringle, M. S. & Zhao, X. Matuyama-Brunhes reversal and Kamikatsura event on Maui: paleomagnetic directions, 40Ar/39Ar ages and implications. Earth Planet. Sci. Lett. 222, 667–684 (2004)

    Article  ADS  CAS  Google Scholar 

  18. Brown, L., Singer, B. S., Pickens, J. & Jicha, B. Paleomagnetic directions and 40Ar/39Ar ages from the Tatara-San Pedro volcanic complex, Chilean Andes: Lava record of a Matuyama-Brunhes precursor? J. Geophys. Res. Solid Earth 109(B12), doi:10.1029/2004JB003007 (2004)

  19. Love, J. J. & Mazaud, A. A database for the Matuyama-Brunhes magnetic reversal. Phys. Earth Planet. Inter. 103, 207–245 (1997)

    Article  ADS  Google Scholar 

  20. Chauvin, A., Roperch, P. & Duncan, R. A. Records of geomagnetic reversals from volcanic islands of French Polynesia 2. Paleomagnetic study of a flow sequence (1.2 to 0.6 Ma) from the Island of Tahiti and discussion of reversal models. J. Geophys. Res. 95, 2727–2752 (1990)

    Article  ADS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  22. Brown, L., Pickens, J. & Singer, B. Matuyama-Brunhes transition recorded in lava flows of the Chilean Andes: Evidence for dipolar fields during reversals. Geology 22, 299–302 (1994)

    Article  ADS  Google Scholar 

  23. Renne, P. R. et al. Intercalibration of standards, absolute ages and uncertainties in 40Ar/39Ar dating. Chem. Geol. 145, 117–152 (1998)

    Article  ADS  CAS  Google Scholar 

  24. Tauxe, L., Herbert, T., Shackleton, N. J. & Kok, Y. S. Astronomical calibration of the Matuyama-Brunhes boundary: Consequences for magnetic remanence acquisition in marine carbonates and the Asian loess sequences. Earth Planet. Sci. Lett. 140, 133–146 (1996)

    Article  ADS  CAS  Google Scholar 

  25. Hartl, P. & Tauxe, L. A precursor to the Matuyama/Brunhes transition-field instability as recorded in pelagic sediments. Earth Planet. Sci. Lett. 138, 121–135 (1996)

    Article  ADS  CAS  Google Scholar 

  26. Prévot, M., Mankinen, E. A., Gromme, C. S. & Coe, R. S. How the geomagnetic field vector reverses polarity. Nature 316, 230–234 (1985)

    Article  ADS  Google Scholar 

  27. Hoffman, K. A. & Singer, B. S. Regionally recurrent paleomagnetic transitional fields and mantle proccesses. in Timescales of the Paleomagnetic Field (eds Channell, J. E. T., Kent, D. V., Lowrie, W. & Meert, J.) 223–243 (Am. Geophys. Un. Geophys. Monogr. 145, 2004)

    Google Scholar 

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

    Google Scholar 

Download references


We thank J. Pickens, M. Relle, A. Battle, L. Powell and R. Allen for assistance with field work, argon and palaeomagnetic analyses, and graphics. This study was supported by the US NSF.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Brad S. Singer.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Table S1

This file contains a spreadsheet with a single table of argon isotope data and age calculations. Complete 40Ar/39Ar Analyses of transitionally magnetized lava flows from Punaruu Valley, Tahiti. (PDF 20 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Singer, B., Hoffman, K., Coe, R. et al. Structural and temporal requirements for geomagnetic field reversal deduced from lava flows. Nature 434, 633–636 (2005).

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