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.

Efficient mixing of the solar nebula from uniform Mo isotopic composition of meteorites


The abundances of elements and their isotopes in our Galaxy show wide variations, reflecting different nucleosynthetic processes in stars and the effects of Galactic evolution1. These variations contrast with the uniformity of stable isotope abundances for many elements in the Solar System2,3, which implies that processes efficiently homogenized dust and gas from different stellar sources within the young solar nebula. However, isotopic heterogeneity has been recognized on the subcentimetre scale in primitive meteorites4,5, indicating that these preserve a compositional memory of their stellar sources. Small differences in the abundance of stable molybdenum isotopes in bulk rocks of some primitive6,7,8 and differentiated7,9 meteorites, relative to terrestrial Mo, suggest large-scale Mo isotopic heterogeneity between some inner Solar System bodies, which implies physical conditions that did not permit efficient mixing of gas and dust. Here we report Mo isotopic data for bulk samples of primitive and differentiated meteorites that show no resolvable deviations from terrestrial Mo. This suggests efficient mixing of gas and dust in the solar nebula at least to 3 au from the Sun, possibly induced by magnetohydrodynamic instabilities10. These mixing processes must have occurred before isotopic fractionation of gas-phase elements and volatility-controlled chemical fractionations were established.

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

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Isotopic composition of Mo in meteorites.
Figure 2: Isotopic composition of Mo in bulk Allende and CAI 3659-B.


  1. Wallerstein, G. et al. Synthesis of the elements in stars: forty years of progress. Rev. Mod. Phys. 69, 995–1084 (1997)

    ADS  CAS  Article  Google Scholar 

  2. Suess, H. E. & Urey, H. C. Abundances of the elements. Rev. Mod. Phys. 28, 53–74 (1956)

    ADS  CAS  Article  Google Scholar 

  3. Anders, E. & Grevesse, N. Abundances of the elements: Meteoritic and solar. Geochim. Cosmochim. Acta 53, 197–214 (1989)

    ADS  CAS  Article  Google Scholar 

  4. Anders, E. & Zinner, E. Interstellar grains in primitive meteorites: Diamond, silicon carbide, and graphite. Meteoritics 28, 490–514 (1993)

    ADS  CAS  Article  Google Scholar 

  5. Harper, C. L. in Nuclei in the Cosmos (eds Käppeler, F. & Wisshak, K.) 113–126 (IOP Publishing, Bristol, 1993)

    Google Scholar 

  6. Yin, Q., Jacobsen, S. B. & Yamashita, K. Diverse supernova sources of pre-solar material inferred from molybdenum isotopes in meteorites. Nature 415, 881–883 (2002)

    ADS  CAS  Article  Google Scholar 

  7. Dauphas, N., Marty, B. & Reisberg, L. Molybdenum evidence for inherited planetary scale isotope heterogeneity of the protosolar nebula. Astrophys. J. 565, 640–644 (2002)

    ADS  CAS  Article  Google Scholar 

  8. Dauphas, N., Marty, B. & Reisberg, L. Molybdenum nucleosynthetic dichotomy revealed in primitive meteorites. Astrophys. J. 569, L139–L142 (2002)

    ADS  CAS  Article  Google Scholar 

  9. Qi Lu & Masuda, A. in Origin of Elements in the Solar System (ed. Manuel, O.) 385–400 (Kluwer/Plenum, New York, 2000)

    Google Scholar 

  10. Stone, J. M., Gammie, C. F., Balbus, S. A. & Hawley, J. F. in Protostars and Planets IV (eds Mannings, V., Boss, A. P. & Russell, S. S.) 589–611 (Univ. Arizona Press, Tucson, 2000)

    Google Scholar 

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

    ADS  CAS  Article  Google Scholar 

  12. Lewis, R. S., Anders, E., Wright, I. P., Norris, S. J. & Pillinger, C. T. Isotopically anomalous nitrogen in primitive meteorites. Nature 305, 767–771 (1983)

    ADS  CAS  Article  Google Scholar 

  13. Thiemens, M. H. & Heidenreich, J. E. III The mass-independent fractionation of oxygen: A novel isotope effect and its possible cosmochemical implications. Science 219, 1073–1075 (1983)

    ADS  CAS  Article  Google Scholar 

  14. Clayton, R. N. Self-shielding in the solar nebula. Nature 415, 860–861 (2002)

    ADS  CAS  Article  Google Scholar 

  15. Lee, T., Shu, F. H., Shang, H., Glassgold, A. E. & Rehm, K. E. Protostellar cosmic rays and extinct radioactivities in meteorites. Astrophys. J. 506, 898–912 (1998)

    ADS  CAS  Article  Google Scholar 

  16. Shukolyukov, A. & Lugmair, G. W. Manganese-chromium isotope systematics of Ivuna, Kainsaz and other carbonaceous chondrites. Lunar Planet. Sci. XXXIV, 1279 (2003)

    ADS  Google Scholar 

  17. Niederer, F. R., Papanastassiou, D. A. & Wasserburg, G. J. Absolute isotopic abundances of Ti in meteorites. Geochim. Cosmochim. Acta 49, 835–851 (1985)

    ADS  CAS  Article  Google Scholar 

  18. Dauphas, N., Marty, B. & Reisberg, L. Inference on terrestrial genesis from molybdenum isotope systematics. Geophys. Res. Lett. 29, 1084 (2002)

    ADS  Article  Google Scholar 

  19. Becker, H. & Walker, R. J. Ruthenium isotopic composition of terrestrial materials, iron meteorites and chondrites. Lunar Planet. Sci. XXXIII, 1018 (2002)

    ADS  Google Scholar 

  20. Becker, H. & Walker, R. J. In search of extant Tc in the early solar system: 98Ru and 99Ru abundances in iron meteorites and chondrites. Chem. Geol. 196, 43–56 (2003)

    ADS  CAS  Article  Google Scholar 

  21. Schönbächler, M., Lee, D.-C., Halliday, A. N. & Rehkämper, M. Uniformity of zirconium isotopic compositions in the inner solar system. Lunar Planet. Sci. XXXIII, 1283 (2002)

    ADS  Google Scholar 

  22. Pernicka, E. & Wasson, J. T. Ru, Re, Os, Pt and Au in iron meteorites. Geochim. Cosmochim. Acta 51, 1717–1726 (1987)

    ADS  CAS  Article  Google Scholar 

  23. Becker, H., Morgan, J. W., Walker, R. J., MacPherson, G. J. & Grossman, J. N. Rhenium-osmium systematics of calcium-aluminium-rich inclusions in carbonaceous chondrites. Geochim. Cosmochim. Acta 65, 3379–3390 (2001)

    ADS  CAS  Article  Google Scholar 

  24. McCulloch, M. T. & Wasserburg, G. J. Barium and neodymium isotopic anomalies in the Allende meteorite. Astrophys. J. 220, L15–L19 (1978)

    ADS  CAS  Article  Google Scholar 

  25. Shu, F. H., Shang, H. & Lee, T. Toward an astrophysical theory of chondrites. Science 271, 1545–1552 (1996)

    ADS  CAS  Article  Google Scholar 

  26. Nier, A. O. A redetermination of the relative abundances of the isotopes of carbon, nitrogen, oxygen, argon and potassium. Phys. Rev. 77, 789–793 (1950)

    ADS  CAS  Article  Google Scholar 

  27. Qi Lu & Masuda, A. The isotopic composition and atomic weight of molybdenum. Int. J. Mass Spectrom. Ion Proc. 130, 65–72 (1994)

    ADS  Article  Google Scholar 

  28. Russell, W. A., Papanastassiou, D. A. & Tombrello, T. A. Ca isotope fractionation on the Earth and other solar system materials. Geochim. Cosmochim. Acta 42, 1075–1090 (1978)

    ADS  CAS  Article  Google Scholar 

Download references


We thank R. Clarke and G. MacPherson for providing the meteorite samples, N. Dauphas, H. Palme, D. Papanastassiou, A. Pietruszka and Q. Yin for discussions, and P. Tomascak for comments on the manuscript and technical support in the laboratory. Comments by S. Jacobsen have improved the presentation of various issues in this manuscript.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Harry Becker.

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

Becker, H., Walker, R. Efficient mixing of the solar nebula from uniform Mo isotopic composition of meteorites. Nature 425, 152–155 (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