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Mass-independent fractionation of titanium isotopes and its cosmochemical implications


Isotopes of heavy elements are produced in various amounts by nuclear processes in stars1,2. Consequently, the presence of isotopic anomalies in the Solar System is considered to reflect the presence of presolar grains condensed in previous generations of stars3 and not a (proto-) Solar System process. However, for oxygen, the major rock-forming element, it has been shown that physico-chemical reactions applicable to the presolar cloud or the protoplanetary disk were a possible source of isotopic variations due to mass-independent isotopic fractionation (MIF)4,5. Here we show that MIF effects are not restricted to oxygen, but can also be produced for titanium. Titanium-rich grains experimentally condensed from a TiCl4(g)/C5H12(g) plasma exhibit MIF effects from −25% to +120% for all Ti isotopic ratios. These large Ti isotopic variations follow the model developed for oxygen MIF6 and mimic the Ti isotopic anomalies observed in some presolar grains. This effect is ascribed to the reactions between chemically indistinguishable isotopes6 and could contribute to the complexity of isotopic anomalies observed in Solar System materials1,7,8,9,10,11,12,13,14.

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Fig. 1: Ti isotope ratios in OM deposited from a TiCl4/C5H12 plasma.
Fig. 2: Ti isotopic variations in OM deposited from a TiCl4/C5H12 plasma.
Fig. 3: Ti isotopic compositions.
Fig. 4

Data availability

The data that support the plots within this paper and other findings of this study are available in the Supplementary Information or from the corresponding author upon reasonable request.


  1. 1.

    Dauphas, N. & Schauble, E. A. Mass fractionation laws, mass-independent effects, and isotopic anomalies. Annu. Rev. Earth Planet. Sci. 44, 709–783 (2016).

    ADS  Article  Google Scholar 

  2. 2.

    Birck, J. L. An overview of isotopic anomalies in extraterrestrial materials and their nucleosynthetic heritage. Rev. Mineral. Geochem. 55, 25–64 (2004).

    Article  Google Scholar 

  3. 3.

    Clayton, R. N., Grossman, L. & Mayeda, T. K. A component of primitive nuclear composition in carbonaceous meteorites. Science 182, 485–488 (1973).

    ADS  Article  Google Scholar 

  4. 4.

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

    ADS  Article  Google Scholar 

  5. 5.

    Thiemens, M. H. Introduction to chemistry and applications in nature of mass indepedendent isotope effects special feature. Proc. Natl Acad. Sci. USA 110, 17631–17637 (2013).

    ADS  Article  Google Scholar 

  6. 6.

    Reinhardt, P. & Robert, F. On the mass independent isotopic fractionation in ozone. Chem. Phys. 513, 287–294 (2018).

    Article  Google Scholar 

  7. 7.

    Zinner, E. K. et al. NanoSIMS isotopic analysis of small presolar grains: search for Si3N4 grains from AGB stars and Al and Ti isotopic compositions of rare presolar SiC grains. Geochim. Cosmochim. Acta 71, 4786–4813 (2007).

    ADS  Article  Google Scholar 

  8. 8.

    Ireland, T. R., Zinner, E. K. & Amari, S. Isotopically anomalous Ti in presolar SiC from the Murchison meteorite. Astrophys. J. 376, L53–L56 (1991).

    ADS  Article  Google Scholar 

  9. 9.

    Huss, G. R. & Smith, J. B. Titanium isotopic compositions of well-characterized silicon carbide grains from Orgueil (CI): implications for s-process nucleosynthesis. Meteor. Planet. Sci. 42, 1055–1075 (2007).

    ADS  Article  Google Scholar 

  10. 10.

    Leya, I., Schönbächler, M., Wiechert, U., Krähenbühl, U. & Halliday, A. Titanium isotopes and the radial heterogeneity of the solar system. Earth Planet. Sci. Lett. 266, 233–244 (2008).

    ADS  Article  Google Scholar 

  11. 11.

    Trinquier, A. et al. Origin of nucleosynthetic isotope heterogeneity in the solar protoplanetary disk. Science 324, 374–376 (2009).

    ADS  Article  Google Scholar 

  12. 12.

    Davis, A. M. et al. Titanium isotopes and rare earth patterns in CAIs: evidence for thermal processing and gas-dust decoupling in the protoplanetary disk. Geochim. Cosmochim. Acta 221, 275–295 (2018).

    ADS  Article  Google Scholar 

  13. 13.

    Gyngard, F., Amari, S., Zinner, E. K. & Marhas, K. K. Correlated silicon and titanium isotopic compositions of presolar SiC grains from the Murchison CM2 chondrite. Geochim. Cosmochim. Acta 221, 145–161 (2018).

    ADS  Article  Google Scholar 

  14. 14.

    Nguyen, A. N., Nittler, L. R., Alexander, C. M. O. ’D. & Hoppe, P. Titanium isotopic compositions of rare presolar SiC grain types from the Murchison meteorite. Geochim. Cosmochim. Acta 221, 162–181 (2018).

    ADS  Article  Google Scholar 

  15. 15.

    Young, E. D., Galy, A. & Nagahara, H. Kinetic and equilibrium mass-dependent isotope fractionation laws in nature and their geochemical and cosmochemical significance. Geochim. Cosmochim. Acta 66, 1095–1104 (2002).

    ADS  Article  Google Scholar 

  16. 16.

    Tartese, R., Chaussidon, M., Gurenko, A., Delarue, F. & Robert, F. Insights into the origin of the carbonaceous chondrite organics from their triple oxygen isotope composition. Proc. Natl Acad. Sci. USA 115, 8535–8540 (2018).

    ADS  Article  Google Scholar 

  17. 17.

    Kööp, L. et al. A link between oxygen, calcium and titanium isotopes in 26Al-poor hibonite-rich CAIs from Murchison and implications for the heterogeneity of dust reservoirs in the solar nebula. Geochim. Cosmochim. Acta 189, 70–95 (2016).

    ADS  Article  Google Scholar 

  18. 18.

    Yurimoto, H. & Kuramoto, K. Molecular cloud origin for the oxygen isotope heterogeneity in the solar system. Science 305, 1763–1766 (2004).

    ADS  Article  Google Scholar 

  19. 19.

    Lodders, K. Titanium and vanadium chemistry in low-mass dwarf stars. Astrophys. J. 577, 974–985 (2002).

    ADS  Article  Google Scholar 

  20. 20.

    Reinhardt, P. & Robert, F. Mass independent isotope fractionation in ozone. Earth Planet. Sci. Lett. 368, 195–203 (2013).

    ADS  Article  Google Scholar 

  21. 21.

    Robert, F. et al. Hydrogen isotope fractionation in methane plasma. Proc. Natl Acad. Sci. USA 114, 870–874 (2017).

    ADS  Article  Google Scholar 

  22. 22.

    Robert, F. The common property of isotopic anomalies in meteorites. Astron. Astrophys. 415, 1167–1176 (2004).

    ADS  Article  Google Scholar 

  23. 23.

    Marcus, R. A. Mass-independent isotope effect in the earliest processed solids in the solar system: a possible chemical mechanism. J. Chem. Phys. 121, 8201–8211 (2004).

    ADS  Article  Google Scholar 

  24. 24.

    Gao, Y. Q. & Marcus, R. A. On the theory of the strange and unconventional isotopic effects in ozone formation. J. Chem. Phys. 116, 137–154 (2002).

    ADS  Article  Google Scholar 

  25. 25.

    Babikov, D. Recombination reactions as a possible mechanism of mass-independent fractionation of sulfur isotopes in the Archean atmosphere of Earth. Proc. Natl Acad. Sci. USA 114, 3062–3067 (2017).

    ADS  Article  Google Scholar 

  26. 26.

    Murphy, A. B. Formation of titanium nanoparticles from a titanium tetrachloride plasma. J. Phys. D 37, 2841 (2004).

    ADS  Article  Google Scholar 

  27. 27.

    Biron, K., Derenne, S., Robert, F. & Rouzaud, J. N. Toward an experimental synthesis of the chondritic insoluble organic matter. Meteor. Planet. Sci. 50, 1408–1422 (2015).

    ADS  Article  Google Scholar 

  28. 28.

    Janssen, C., Guenther, J., Mauersberger, K. & Krankowsky, D. Kinetic origin of the ozone isotope effect: a critical analysis of enrichments and rate coefficients. Phys. Chem. Chem. Phys. 3, 4718–4721 (2001).

    Article  Google Scholar 

  29. 29.

    Schinke, R. & Fleurat-Lessard, P. The effect of zero-point energy differences on the isotope dependence of the formation of ozone: a classical trajectory study. J. Chem. Phys. 122, 094317 (2005).

    ADS  Article  Google Scholar 

  30. 30.

    Ivanov, M. V. & Babikov, D. On molecular origin of mass-independent fractionation of oxygen isotopes in the ozone forming recombination reaction. Proc. Natl Acad. Sci. USA 110, 17708–17713 (2013).

    ADS  Article  Google Scholar 

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F.R. acknowledges support (Overheads) of ERC Advanced Grant PaleoNanoLife (PI: F.R.; grant. no. 161764). R.T. acknowledges support from the UK Science and Technology Facilities Council (grant no. ST/P005225/1). At The University of Manchester, the NanoSIMS was funded by UK Research Partnership Investment Funding (UKRPIF) Manchester RPIF Round 2, and the installation of a Hyperion RF plasma ion source was supported by the Henry Royce Institute for Advanced Materials, funded through EPSRC grant nos EP/R00661X/1, EP/P025021/1 and EP/P025498/1. M.C. acknowledges support from ANR Cradle (grant no. ANR-15-CE31-0004-01).

Author information




F.R. designed the project and provided samples for this study. R.T. collected and analysed the NanoSIMS data. F.R., R.T., Z.D. and M.C. interpreted the cosmochemistry results and wrote the paper. G.L. interpreted the plasma physics results. B.D. and M.R. obtained and interpreted the microscopic images. P.R. participated in the interpretation of the Ti-MIF effects in terms of theoretical physics.

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Correspondence to François Robert.

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The authors declare no competing interests.

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Peer review information Nature Astronomy thanks Andrew Davis, Justin Simon and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–6, Table 1, discussion and references.

Supplementary Data

Excel version of Supplementary Table 1.

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Robert, F., Tartèse, R., Lombardi, G. et al. Mass-independent fractionation of titanium isotopes and its cosmochemical implications. Nat Astron 4, 762–768 (2020).

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