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.

Contemporaneous formation of chondrules and refractory inclusions in the early Solar System


Chondrules and calcium-aluminium-rich inclusions (CAIs) are preserved materials from the early history of the Solar System, where they resulted from thermal processing of pre-existing solids during various flash heating episodes which lasted for several million years1. CAIs are believed to have formed about two million years before the chondrules2,3,4,5. Here we report the discovery of a chondrule fragment embedded in a CAI. The chondrule's composition is poor in 16O, while the CAI has a 16O-poor melilite (Ca, Mg, Al-Silicate) core surrounded by a 16O-rich igneous mantle. These observations, when combined with the previously reported CAI-bearing chondrules6,7,8,9, strongly suggest that the formation of chondrules and CAIs overlapped in time and space, and that there were large fluctuations in the oxygen isotopic compositions in the solar nebula probably synchronizing astrophysical pulses.

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

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type



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

Figure 1: Back-scattered electron image of the chondrule-bearing CAI.
Figure 2: Oxygen-isotopic composition of minerals in the chondrule-bearing CAI.
Figure 3: Schematic view of CAI and chondrule formation.


  1. Wood, J. A. in Chondrules and the Protoplanetary Disk (eds Hewins, R. H., Jones, R. H. & Scott, E. R. D.) 55–69 (Cambridge Univ. Press, Cambridge, 1996)

    Google Scholar 

  2. Tatsumoto, M., Unruh, D. M. & Desborough, G. A. U-Th-Pb and Rb-Sr systematics of Allende and U-Th-Pb systematics of Orgueil. Geochim. Cosmochim. Acta 40, 617–634 (1976)

    Article  ADS  CAS  Google Scholar 

  3. Chen, J. H. & Tilton, G. R. Isotopic lead investigations on the Allende carbonaceous chondrite. Geochim. Cosmochim. Acta 40, 635–643 (1976)

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  6. 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 

  7. Srinivasan, G. & Bischoff, A. Magnesium-aluminum study of hibonites within a chondrule-like object from Sharps (H3). Meteorit. Planet. Sci. 32, A148 (1998)

    Google Scholar 

  8. Krot, A. N. et al. Mineralogical, aluminum-magnesium, and oxygen-isotopic studies of the relic calcium-aluminum-rich inclusions in chondrules. Meteorit. Planet. Sci. 34, A68–A69 (1999)

    Article  ADS  Google Scholar 

  9. Maruyama, S., Yurimoto, H. & Sueno, S. Oxygen isotope evidence regarding the formation of spinel-bearing chondrules. Earth Planet. Sci. Lett. 169, 165–171 (1999)

    Article  ADS  CAS  Google Scholar 

  10. MacPherson, G. J., Wark, D. A. & Armstrong, J. T. in Meteorites and the Early Solar System (eds Kerridge, J. F. & Matthews, M. S.) 746–807 (Univ. Arizona Press, Tucson, 1988)

    Google Scholar 

  11. Noguchi, T. Texture and chemical composition of pyroxenes in chondrules in carbonaceous and unequilibrated ordinary chondrites. Proc. NIPR Symp. Antarct. Meteorites 2, 169–199 (1989)

    CAS  Google Scholar 

  12. Jones, R. H., Saxton, J. M., Lyon, I. C. & Turner, G. Oxygen isotopes in chondrule olivine and isolated olivine grains from the CO3 chondrite, ALHA77307. Meteorit. Planet. Sci. 35, 849–857 (2000)

    Article  ADS  CAS  Google Scholar 

  13. Wasson, J. T., Rubin, A. E. & Yurimoto, H. CO chondrule evidence for a drift in the nebular oxygen-isotopic composition. [abstract]. Meteorit. Planet. Sci. 35, A166–A167 (2000)

    Google Scholar 

  14. Stolper, E. Crystallization sequences of Ca-Al-rich inclusions from Allende: An experimental study. Geochim. Cosmochim. Acta 46, 2159–2180 (1982)

    Article  ADS  CAS  Google Scholar 

  15. Itoh, S., Kojima, H., Yurimoto, H. . Lunar Planet. Sci. XXXI, 1323 (2000) [CD-ROM]

    ADS  Google Scholar 

  16. Stolper, E. & Paque, J. M. Crystallization sequences of Ca-Al-rich inclusions from Allende: The effects of cooling rate and maximum temperature. Geochim. Cosmochim. Acta 50, 1785–1806 (1986)

    Article  ADS  CAS  Google Scholar 

  17. Yurimoto, H., Morioka, M. & Nagasawa, H. Diffusion in single-crystals of melilite: I. Oxygen. Geochim. Cosmochim. Acta 53, 2387–2394 (1989)

    Article  ADS  CAS  Google Scholar 

  18. Lasaga, A. C. in Kinetics and Equilibrium in Mineral Reactions (ed. Saxena, S. K.)) 81–114 (Springer, New York, 1983)

    Book  Google Scholar 

  19. Wasson, J. T., Yurimoto, H. & Russell, S. S. 16O-rich melilite in CO3.0 chondrites; possible formation of common, 16O-poor melilite by aqueous alteration. Geochim. Cosmochim. Acta 65, 4539–4549 (2001)

    Article  ADS  CAS  Google Scholar 

  20. Kojima, T., Yada, S. & Tomeoka, K. Ca-Al-rich inclusions in three Antarctic CO3 chondrites, Yamato-81020, Yamato-82050 and Yamato-790992: Record of low-temperature alteration. Proc. NIPR Symp. Antarct. Meteorites 8, 79–96 (1995)

    CAS  Google Scholar 

  21. Itoh, S., Kojima, H. & Yurimoto, H. Petrography and oxygen isotopic compositions in refractory inclusions from CO chondrites. Geochim. Cosmochim. Acta (in the press)

  22. Shu, F. H., Shang, H., Glassgold, A. E. & Lee, T X-rays and fluctuating X-winds from protostars. Science 277, 1475–1749 (1997)

    Article  ADS  CAS  Google Scholar 

  23. 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 

  24. Gounelle, M. et al. Extinct radioactivities and protosolar cosmic rays: Self-shielding and light elements. Astrophys. J. 548, 1051–1070 (2001)

    Article  ADS  CAS  Google Scholar 

  25. Yurimoto, H., Asada, Y. & Hirai, K. Oxygen isotopic composition of fine-grained CAIs and genetic relation to coarse-grained CAIs. Meteorit. Planet. Sci. 36, A230 (2001)

    Google Scholar 

  26. Clayton, R. N. Oxygen isotopes in meteorites. Annu. Rev. Earth Planet Sci. 21, 115–149 (1993)

    Article  ADS  CAS  Google Scholar 

  27. Krot, A. N., McKeegan, K. D., Leshin, L. A., MacPherson, G. J. & Scott, E. R. D. Existence of an 16O-rich gaseous reservoir in the solar nebula. Science 295, 1051–1054 (2002)

    Article  ADS  CAS  Google Scholar 

  28. Krot, A. N. et al. Refractory calcium-aluminum-rich inclusions and aluminum-diopside-rich chondrules in the metal-rich chondrites Hammadah al Hamra 237 and Queen Alexandra Range 94411. Meteorit. Planet. Sci. 36, 1189–1216 (2001)

    Article  ADS  CAS  Google Scholar 

  29. Cameron, A. G. W. The first ten million years in the solar nebula. Meteoritics 30, 133–161 (1995)

    Article  ADS  CAS  Google Scholar 

  30. Yurimoto, H., Ito, M. & Nagasawa, H. Oxygen isotope exchange between refractory inclusion in Allende and solar nebula gas. Science 282, 1874–1877 (1998)

    Article  ADS  CAS  Google Scholar 

Download references


We thank J. T. Wasson and A. E. Rubin for loaning us the thin section and for discussions. We also thank A. Meibom, A. N. Krot and T. J. Fagan for discussions and for improving the English of this Letter. This work was supported by Monbu-Kagaku-sho grants.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Hisayoshi Yurimoto.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

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

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