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.

Mg isotope evidence for contemporaneous formation of chondrules and refractory inclusions

A Corrigendum to this article was published on 30 June 2005


Primitive or undifferentiated meteorites (chondrites) date back to the origin of the Solar System1, and thus preserve a record of the physical and chemical processes that occurred during the earliest evolution of the accretion disk surrounding the young Sun. The oldest Solar System materials present within these meteorites are millimetre- to centimetre-sized calcium-aluminium-rich inclusions (CAIs) and ferromagnesian silicate spherules (chondrules), which probably originated by thermal processing of pre-existing nebula solids2,3,4. Chondrules are currently believed to have formed 2–3 million years (Myr) after CAIs (refs 5–10)—a timescale inconsistent with the dynamical lifespan of small particles in the early Solar System11. Here, we report the presence of excess 26Mg resulting from in situ decay of the short-lived 26Al nuclide in CAIs and chondrules from the Allende meteorite. Six CAIs define an isochron corresponding to an initial 26Al/27Al ratio of (5.25 ± 0.10) × 10-5, and individual model ages with uncertainties as low as ± 30,000 years, suggesting that these objects possibly formed over a period as short as 50,000 years. In contrast, the chondrules record a range of initial 26Al/27Al ratios from (5.66 ± 0.80) to (1.36 ± 0.52) × 10-5, indicating that Allende chondrule formation began contemporaneously with the formation of CAIs, and continued for at least 1.4 Myr. Chondrule formation processes recorded by Allende and other chondrites may have persisted for at least 2–3 Myr in the young Solar System.

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

Access options

Rent or buy this article

Get just this article for as long as you need it


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

Figure 1: Al–Mg evolution diagrams.
Figure 2: Mg stable isotope composition (δ25Mg) versus excess 26Mg (δ26Mg*) diagram.


  1. Alexander, C. M. O'D., Boss, A. P. & Carlson, R. W. The early evolution of the inner solar system: A meteoritic perspective. Science 293, 64–68 (2001)

    Article  ADS  CAS  Google Scholar 

  2. MacPherson, G. J. in Meteorites, Comets and Planets (ed. Davis, A. M.) 201–246, Vol. 1 of Treatise on Geochemistry (eds Holland, H. D. & Turekian, K. K.) (Elsevier-Pergamon, Oxford, 2003).

  3. Rubin, A. E. Petrologic, geochemical and experimental constraints on models of chondrule formation. Earth Sci. Rev. 50, 3–27 (2000)

    Article  ADS  CAS  Google Scholar 

  4. Shu, F. H., Shang, H., Gounelle, M., Glassgold, A. E. & Lee, T. The origin of chondrules and refractory inclusions in chondritic meteorites. Astrophys. J. 548, 1029–1050 (2001)

    Article  ADS  Google Scholar 

  5. Russell, S. S., Srinivasan, G., Huss, G. R., Wasserburg, G. J. & MacPherson, G. J. Evidence for widespread 26Al in the solar nebula and constraints for nebula time scales. Science 273, 757–762 (1996)

    Article  ADS  CAS  PubMed  Google Scholar 

  6. Kita, N. T., Nagahara, S. & Morishita, Y. A short duration of chondrule formation in the solar nebula: Evidence from Al-26 in Semarkona ferromagnesian chondrules. Geochim. Cosmochim. Acta 64, 3913–3922 (2000)

    Article  ADS  CAS  Google Scholar 

  7. Huss, G. R., MacPherson, G. J., Wasserburg, G. J., Russell, S. S. & Srinivasan, G. Aluminum-26 in calcium-aluminum-rich inclusions and chondrules from unequilibrated ordinary chondrites. Meteorit. Planet. Sci. 36, 975–997 (2001)

    Article  ADS  CAS  Google Scholar 

  8. Mostefaoui, S. et al. The relative formation ages of ferromagnesian chondrules inferred from their initial aluminum-26/aluminum-27 ratios. Meteorit. Planet. Sci. 37, 421–438 (2002)

    Article  ADS  CAS  Google Scholar 

  9. Hsu, W. B., Huss, G. R. & Wasserburg, G. J. Al-Mg systematics of CAIs, POI, and ferromagnesian chondrules from Ningqiang. Meteorit. Planet. Sci. 38, 35–48 (2003)

    Article  ADS  CAS  Google Scholar 

  10. Amelin, Y., Krot, A. N., Hutcheon, I. D. & Ulyanov, A. A. Lead isotopic ages of chondrules and calcium-aluminium-rich inclusions. Science 297, 1678–1683 (2002)

    Article  ADS  CAS  PubMed  Google Scholar 

  11. Adachi, I., Hayashi, C. & Nakazawa, K. Gas drag effect on elliptic motion of a solid body in primordial solar nebula. Prog. Theor. Phys. 56, 1756–1771 (1976)

    Article  ADS  Google Scholar 

  12. Busso, M., Gallino, R. & Wasserburg, G. J. Nucleosynthesis in asymptotic giant branch stars: Relevance for Galactic enrichment and solar system formation. Annu. Rev. Astron. Astrophys. 37, 239–309 (1999)

    Article  ADS  CAS  Google Scholar 

  13. Goswami, J. N. Short-lived nuclides in the early solar system: the stellar connection. New Astron. Rev. 48, 125–132 (2004)

    Article  ADS  CAS  Google Scholar 

  14. Sahijpal, S., Goswami, J. N., Davis, A. M., Grossman, L. & Lewis, R. S. A stellar origin for the short-lived nuclides in the early Solar System. Nature 391, 559–561 (1998)

    Article  ADS  CAS  Google Scholar 

  15. Wasserburg, G. J., Gallino, R., Busso, M., Goswami, J. N. & Raiteri, C. M. Injection of freshly synthesized 41Ca in the early solar nebula by an asymptotic giant branch star. Astrophys. J. 440, L101–L104 (1995)

    Article  ADS  CAS  Google Scholar 

  16. Marhas, K. K., Goswami, J. N. & Davis, A. M. Short-lived nuclides in hibonite grains from Murchison: Evidence for Solar System evolution. Science 298, 2182–2185 (2002)

    Article  ADS  CAS  PubMed  Google Scholar 

  17. Galy, A., Young, E. D., Ash, R. D. & O'Nions, R. K. The formation of chondrules at high gas pressures in the solar nebula. Science 290, 1751–1753 (2000)

    Article  ADS  CAS  PubMed  Google Scholar 

  18. Urey, H. C. The cosmic abundances of potassium, uranium, and thorium and the heat balances of the Earth, the Moon and Mars. Proc. Natl Acad. Sci. USA 41, 127–144 (1955)

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  19. Srinivasan, G., Goswami, J. N. & Bhandari, N. 26Al in eucrite Piplia Kalan: plausible heat source and formation chronology. Science 284, 1348–1350 (1999)

    Article  ADS  CAS  PubMed  Google Scholar 

  20. Bischoff, A. & Keil, K. Al-rich objects in ordinary chondrites: Related origin of carbonaceous and ordinary chondrites and their constituents. Geochim. Cosmochim. Acta 48, 693–709 (1984)

    Article  ADS  CAS  Google Scholar 

  21. Itoh, S. & Yurimoto, H. Contemporaneous formation of chondrules and refractory inclusions in the early Solar System. Nature 423, 728–731 (2003)

    Article  ADS  CAS  PubMed  Google Scholar 

  22. Amelin, Y., Krot, A. & Twelker, E. Pb isotopic age of the CB chondrite Gujba, and the duration of the chondrule formation interval. Geochim. Cosmochim. Acta 68 Abst. E958 (2004)

  23. Briceño, C. et al. The CIDA-QUEST large-scale survey of Orion OB1: Evidence for rapid disk dissipation in a dispersed stellar population. Science 291, 93–96 (2001)

    Article  ADS  PubMed  Google Scholar 

  24. Podosek, F. A. & Cassen, P. Theoretical, observational, and isotopic estimates of lifetime of the solar nebula. Meteoritics 29, 6–25 (1994)

    Article  ADS  CAS  Google Scholar 

  25. Weidenschilling, S. J., Marzari, F. & Hood, L. L. The origin of chondrules at jovian resonances. Science 279, 681–684 (1998)

    Article  ADS  CAS  PubMed  Google Scholar 

  26. Desch, S. J. & Connolly, H. C. A model of the thermal processing of particles in solar nebula shocks: Application to the cooling rates of chondrules. Meteorit. Planet. Sci. 37, 183–207 (2002)

    Article  ADS  CAS  Google Scholar 

  27. Sanders, I. A. in Chondrules and the protoplanetary disk (eds Hewins, R. H., Jones, R. H. & Scott, E. R. D.) 327–334 (Cambridge Univ. Press, Cambridge, 1996)

    Google Scholar 

  28. McDonough, W. F. & Sun, S.-S. Composition of the Earth. Chem. Geol. 120, 223–253 (1995)

    Article  ADS  CAS  Google Scholar 

  29. Galy, A. et al. Magnesium isotope heterogeneity of the isotopic standard SRM980 and new reference materials for magnesium-isotope-ratio measurements. J. Anal. Atomic Spectrometry 18, 1352–1356 (2003)

    Article  CAS  Google Scholar 

  30. Richter, F. M., Davis, A. M., Ebel, D. S. & Hashimoto, A. Elemental and isotopic fractionation of type B calcium-, aluminum-rich inclusions: Experiments, theoretical considerations, and constraints on their thermal evolution. Geochim. Cosmochim. Acta 66, 521–540 (2002)

    Article  ADS  CAS  Google Scholar 

Download references


Financial support for this project was provided by the Danish Lithosphere Centre (funded by the Danish National Science Foundation). M.B. is grateful for financial support in the form of an NSERC postdoctoral fellowship. We thank A. Halliday for his review of this paper.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Martin Bizzarro.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Figure 1

Back-scattered electron images and elemental maps of selected chondrules from the Allende meteorite. (PDF 2875 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Bizzarro, M., Baker, J. & Haack, H. Mg isotope evidence for contemporaneous formation of chondrules and refractory inclusions. Nature 431, 275–278 (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