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.

Palaeozoic and Proterozoic zircons from the Mid-Atlantic Ridge


According to the theory of plate tectonics, rocks found in the vicinity of mid-ocean ridges — where oceanic plates are created — should be relatively young (at most several Myr old). Here we report the discovery of zircons with ages of about 330 and 1,600 Myr that were drilled from exposed gabbros beneath the Mid-Atlantic Ridge near the Kane fracture zone1,2,3,4. Age determinations were made using the 207Pb/206Pb evaporation method5 and confirmed with conventional U–Pb dating and ion microprobe (SHRIMP) analysis. We suggest two plausible explanations for the origin of these unusually old zircons. During the opening of the Atlantic, sheared crustal material or delaminated continental lithosphere sank into small roll-like circulation cells6,7 that developed in the shallow mantle at each side of the ridge axis and the material was then transported through these cells to the ridge axis. Alternatively, material from the continental crust has been trapped within the Kane fracture zone since the opening of the Atlantic Ocean basin through a series of transform migrations and ridge jumps8,9, with portions of this material subsequently migrating down the ridge axis.

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: Generalized bathymetric and tectonic map of the Mid-Atlantic Ridge south of the Kane transform.
Figure 2: Scanning electron micrographs of two selected zircons.
Figure 3: Plot of measured 207Pb/206Pb against measured 204Pb/206Pb, used to obtain the 207Pb/206Pb age of single zircon groups.
Figure 4: Concordia diagrams of U–Pb age determinations33.


  1. Cannat, M. & ODP shipboard Scientific Party Leg 153 Probing the foundation of the Mid-Atlantic Ridge. Eos 76, 129–133 (1995).

    Google Scholar 

  2. Werner, C.-D. Data report: geochemistry of rocks and minerals of the gabbro complex from the MARK area. Proc. ODP Sci. Res. 153, 491–504 (1997).

    CAS  Google Scholar 

  3. Werner, C.-D. & Pilot, J. Data report: geochemistry and mineral chemistry of ultramafic rocks from the Kane area (MARK). Proc. ODP Sci. Res. 153, 457–470 (1997).

    CAS  Google Scholar 

  4. Pilot, J., Werner, C.-D. & Tichomirow, W. Further oxygen isotope investigations from an ultramafic profile, hole 920D: alterations by seawater. Terra Nostra 4, 66 (1996).

    Google Scholar 

  5. Kober, B. Single-zircon evaporation combined with Pb+ emitter bedding for 207Pb/206Pb-age determinations using thermal ion mass spectrometry, and implications to zirconology. Contrib. Mineral. Petrol. 96, 63–71 (1987).

    Article  ADS  CAS  Google Scholar 

  6. Nicolas, A. Die Ozeanischen Rücken 140, Fig. 7.7 (Springer, Berlin, (1995)).

  7. Rabinowicz, M., Nicolas, A. & Vigneresse, J. L. Arolling mill effect in asthenosphere beneath oceanic spreading centers. Earth Planet. Sci. Lett. 67, 97–108 (1984).

    Article  ADS  Google Scholar 

  8. Bonatti, E. & Crane, K. Oscillatory spreading explanation of anomalously old uplifted crust near oceanic transforms. Nature 300, 343–345 (1982).

    Article  ADS  Google Scholar 

  9. Kepezhinskas, P. & Dmitiev, D. Continental lithospheric blocks in central Atlantic Ocean. Ofioliti 17, 19–35 (1992).

    Google Scholar 

  10. Cannat, M., Bideau, D. & Bougault, H. Serpentinized peridotites and gabbros in the Mid-Atlantic Ridge axial valley at 15° 37′ N and 16° 52′ N. Earth Planet. Sci. Lett. 109, 87–106 (1992).

    Article  ADS  CAS  Google Scholar 

  11. Karson, J. A. & Winters, A. T. in Ophiolites and their Modern Oceanic Analogues (eds Parsons, L. M., Murton, B. J. & Browning, P.) 107–116 (Spec. Publ. 60, Geol. Soc., Boulder, (1992)).

    Google Scholar 

  12. Pupin, J. P. Zircon and granite petrology. Contrib. Mineral. Petrol. 73, 207–220 (1980).

    Article  ADS  CAS  Google Scholar 

  13. Gaggero, L. & Gazzotti, M. Primary and secondary oxides, sulfides and accessory minerals in Mid-Atlantic gabbros: mineralogy and petrology. Ofioliti 21, 105–116 (1996).

    Google Scholar 

  14. Kelley, D. S. & Malpas, J. Melt-fluid evolution in gabbroic rocks from Hess Deep. Proc. ODP Sci. Res. 147, 213–226 (1996).

    CAS  Google Scholar 

  15. Cannat, M., Ceuleneer, G., Fletscher, J. Localization of ductile strain and the magmatic evolution of gabbroic rocks drilled at the Mid-Atlantic Ridge (23° N). Proc. ODP Sci. Res. 153, 84 (1997).

    Google Scholar 

  16. Tera, F. & Wasserburg, G. J. U-Th-Pb systematics in lunar highland samples from the Luna 20 and Apollo 16 mission. Earth Planet. Sci. Lett. 17, 36–51 (1972).

    Article  ADS  CAS  Google Scholar 

  17. Wendt, I. Radiometric methods in Geochronology. Clausthaler Tektonische Hefte 23, 92–96 (1986). (In German.)

    Google Scholar 

  18. Ludwig, K. R. Effect of initial radioactive-daughter disequilibrium on U-Pb isotope apparent ages of young minerals. J. Res. US Geol. Surv. 5, 663–667 (1977).

    CAS  Google Scholar 

  19. Wendt, I. & Carl, C. U/Pb dating of discordant 0.1 Ma old secondary U minerals. Earth Planet. Sci. Lett. 73, 278–284 (1985).

    Article  ADS  CAS  Google Scholar 

  20. Metzger, K. & Krogstad, E. J. Interpretation of discordant U-Pb zircon ages: an evaluation. J. Metamorphic Geol. 15, 127–140 (1997).

    Article  ADS  Google Scholar 

  21. Lee, J. K. W., Williams, I. S. & Ellis, D. J. Pb, U, and Th diffusion in natural zircon. Nature 390, 159–162 (1997).

    Article  ADS  CAS  Google Scholar 

  22. Kresten, P., Fels, P. & Berggren, G. Kimberlitic zircons — a possible aid in prospecting for kimberlites. Mineral. Deposita (Berl.) 10, 47–56 (1975).

    Article  ADS  CAS  Google Scholar 

  23. Ahrens, L. H., Cherry, R. D. & Erlank, A. J. Observations on the relationship in zircons from granitic rocks and from kimberlites. Geochim. Cosmochim. Acta 31, 2379–2387 (1967).

    Article  ADS  CAS  Google Scholar 

  24. Kinny, P. D., Compston, J., Bristow, J. W. & Williams, I. S. in Kimberlites and Related Rocks Vol. 2(eds Ross, J. et al.) 833–842 (Geol. Soc. Austr. Spec. Publ. 14, Blackwell, Melbourne, (1989)).

    Google Scholar 

  25. Jochum, K. P., Hofmann, A. W., Ito, E., Seufert, H. M. & White, W. M. K, U and Th in mid-ocean ridge basalt glasses and heat production, K/U and K/RB in the mantle. Nature 306, 431–436 (1983).

    Article  ADS  CAS  Google Scholar 

  26. Hofman, A. W. Chemical differentiation of the Earth: the relationship between mantle, continental crust, and oceanic crust. Earth Planet. Sci. Lett. 90, 297–314 (1988).

    Article  ADS  Google Scholar 

  27. Chen, Y. D., O'Reilley, S. Y., Kinny, P. D. & Griffin, W. L. Dating lower crust and upper mantle events: an ion microprobe study from kimberlitic pipes, South Australia. Lithos 32, 77–94 (1994).

    Article  ADS  CAS  Google Scholar 

  28. Bonatti, E. et al. Lower Cretaceous deposits trapped near the equatorial Mid-Atlantic Ridge. Nature 380, 518–520 (1996).

    Article  ADS  CAS  Google Scholar 

  29. Beljatsky, B. V. et al. Precambrian granitic gneiss from MAR (26° N): results of U-Pb and Sm-Nd-isotopic investigations. Geomija 8, 876–880 (1997). (In Russian.)

    Google Scholar 

  30. Truchalev, A. I. et al. Old K-Ar-age of an metagabbro and a granite-gneiss dredged at the axial part of the Mid-Atlantic Ridge, 26° N. Dokl. Akad. Nauk 311, 1447–1452 (1990). (In Russian.)

    Google Scholar 

  31. White, R. & McKenzie, D. Magmatism at rift zones: the generation of volcanic continental margins and flood basalts. J. Geophys. Res. 94(6), 7685–7729 (1989).

    Article  ADS  Google Scholar 

  32. Tucholke, B. E. & Schouten, H. Kane fracture zone. Mar. Geophys. Res. 10, 1–39 (1988).

    Article  Google Scholar 

  33. Ludwig, K. R. ISOPLOT — a Plotting and Regression Program for Radiogenic-Isotope DataV2.71 (Open File Rep. 91-445, US Geol. Surv., Denver, (1992)).

    Google Scholar 

  34. Cannat, M. et al. Ultramafic and gabbroic exposures at the Mid-Atlantic Ridge: geological mapping in the 15°N region. Tectonophysics 279, 193–213 (1997).

    Article  ADS  Google Scholar 

  35. York, D. Least squares fitting of a straight line with correlated errors. Earth Planet. Sci. Lett. 5, 320–324 (1969).

    Article  ADS  CAS  Google Scholar 

Download references


We thank P. Herzig and S. Petersen for comments; A. W. Hofmann, B. Hanan, F. Tera and S. Uhlig for discussions; U. Kempe for help with the SEM images; W. Todt (MPI Mainz) for supporting the conventional U-Pb dating; and I. S. Williams (ANU, RSES, Canberra) for SHRIMP datings. This work was supported by the Deutsche Forschungsgemeinschaft.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Joachim Pilot.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Pilot, J., Werner, CD., Haubrich, F. et al. Palaeozoic and Proterozoic zircons from the Mid-Atlantic Ridge. Nature 393, 676–679 (1998).

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