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Upper-mantle volatile chemistry at Oldoinyo Lengai volcano and the origin of carbonatites

Abstract

Carbonatite lavas are highly unusual in that they contain almost no SiO2 and are >50 per cent carbonate minerals. Although carbonatite magmatism has occurred throughout Earth’s history, Oldoinyo Lengai, in Tanzania, is the only currently active volcano producing these exotic rocks1. Here we show that volcanic gases captured during an eruptive episode at Oldoinyo Lengai are indistinguishable from those emitted along mid-ocean ridges, despite the fact that Oldoinyo Lengai carbonatites occur in a setting far removed from oceanic spreading centres. In contrast to lithophile trace elements, which are highly fractionated by the immiscible phase separation that produces these carbonatites, volatiles (CO2, He, N2 and Ar) are little affected by this process. Our results demonstrate that a globally homogenous reservoir exists in the upper mantle and supplies volatiles to both mid-ocean ridges and continental rifts. This argues against an unusually C-rich mantle being responsible for the genesis of Na-rich carbonatite and its nephelinite source magma at Oldoinyo Lengai. Rather, these carbonatites are formed in the shallow crust by immiscibility from silicate magmas (nephelinite), and are stable under eruption conditions as a result of their high Na contents.

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Figure 1: N 2 –He–Ar triangular plot.
Figure 2: N2/36Ar and 40Ar/36Ar ratio diagram.
Figure 3: 4He/40Ar* and CO2/40Ar* ratios of Oldoinyo Lengai gases.

References

  1. Dawson, J. B. Sodium carbonatite lavas from Oldoinyo Lengai, Tanganyika. Nature 195, 1075–1076 (1962)

    ADS  CAS  Article  Google Scholar 

  2. Pik, R., Marty, B. & Hilton, D. R. How many plumes in Africa? The geochemical point of view. Chem. Geol. 226, 100–114 (2006)

    ADS  CAS  Article  Google Scholar 

  3. Keller, J. & Spettel, B. in Carbonatite Volcanism: Oldoinyo Lengai and the Petrogenesis of Natrocarbonatites (eds Bell, K. & Keller, J.) 70–86 (IAVCEI Proc. Volcanol. Vol. 4, Springer, 1995)

    Book  Google Scholar 

  4. Bell, K. & Dawson, J. B. in Carbonatite Volcanism: Oldoinyo Lengai and the Petrogenesis of Natrocarbonatites (eds Bell, K. & Keller, J.) 100–112 (IAVCEI Proc. Volcanol. Vol. 4, Springer, 1995)

    Google Scholar 

  5. Peterson, T. D. Peralkaline nephelinites II. Low pressure fractionation and the hypersodic lavas of Oldoinyo L’engai. Contrib. Mineral. Petrol. 102, 336–346 (1989)

    ADS  CAS  Article  Google Scholar 

  6. Dasgupta, R. & Hirschmann, M. M. Melting in the Earth’s deep upper mantle caused by carbon dioxide. Nature 440, 659–662 (2006)

    ADS  CAS  Article  Google Scholar 

  7. Wyllie, P. J. in Carbonatites: Genesis and Evolution (ed. Bell, K.) 500–540 (Unwin Hyman, 1989)

    Google Scholar 

  8. Dasgupta, R., Hirschmann, M. M. & Smith, N. D. Partial melting experiments of peridotite+CO2 at 3 GPa and genesis of alkalic ocean island basalts. J. Petrol. 48, 2093–2124 (2007)

    ADS  CAS  Article  Google Scholar 

  9. Brantley, S. L. & Koepenick, K. W. Measured carbon dioxide emissions from Oldoinyo Lengai and the skewed distribution of passive volcanic fluxes. Geology 23, 933–936 (1995)

    ADS  CAS  Article  Google Scholar 

  10. Hilton, D. R., Fischer, T. P. & Marty, B. in Noble Gases in Geochemistry and Cosmochemistry (eds Porcelli, D., Ballentine, C. & Wieler, R.) 319–362 (Rev. Mineral. Geochem. Vol. 47, Mineralogical Society of America, 2002)

    Book  Google Scholar 

  11. Fischer, T. P. et al. Subduction and recycling of nitrogen along the Central American margin. Science 297, 1154–1157 (2002)

    ADS  CAS  Article  Google Scholar 

  12. Shaw, A. M., Hilton, D. R., Fischer, T. P., Walker, J. A. & Alvarado, G. Contrasting He-C relationships in Nicaragua and Costa Rica: insights into C cycling through subduction zones. Earth Planet. Sci. Lett. 214, 499–513 (2003)

    ADS  CAS  Article  Google Scholar 

  13. Graham, D. W. in Noble Gases in Geochemistry and Cosmochemistry (eds Porcelli, D., Ballentine, C. & Wieler, R.) 247–317 (Rev. Mineral. Geochem. Vol. 47, Mineralogical Society of America, 2002)

    Book  Google Scholar 

  14. Marty, B. & Zimmermann, L. Volatiles (He, C, N, Ar) in mid-ocean ridge basalts: assessment of shallow-level fractionation and characterization of source composition. Geochim. Cosmochim. Acta 63, 3619–3633 (1999)

    ADS  CAS  Article  Google Scholar 

  15. Braeuer, K., Kaempf, H., Niedermann, S., Strauch, G. & Weise, S. M. Evidence for a nitrogen flux directly derived from the European subcontinental mantle in the Western Eger Rift, Central Europe. Geochim. Cosmochim. Acta 68, 4935–4947 (2004)

    ADS  CAS  Article  Google Scholar 

  16. Sano, Y., Takahata, N., Nishio, Y., Fischer, T. P. & Williams, S. N. Volcanic flux of nitrogen from the Earth. Chem. Geol. 171, 263–271 (2001)

    ADS  CAS  Article  Google Scholar 

  17. Burnard, P. G., Graham, D. W. & Turner, G. Vesicle specific noble gas analyses of “popping rock”: implications for primordial noble gases in earth. Science 276, 568–571 (1997)

    CAS  Article  Google Scholar 

  18. Gilfillan, S. M. V. et al. The noble gas geochemistry of natural CO2 gas reservoirs from the Colorado Plateau and Rocky Mountain provinces, USA. Geochim. Cosmochim. Acta 72, 1174–1198 (2008)

    ADS  CAS  Article  Google Scholar 

  19. Marty, B. & Tolstikhin, I. N. CO2 fluxes from mid-ocean ridges, arcs and plumes. Chem. Geol. 145, 233–248 (1998)

    ADS  CAS  Article  Google Scholar 

  20. Burnard, P. & Toplis, M. Helium solubility in carbonate liquids; potential for generating high 3He/U mantle. Geochim. Cosmochim. Acta 69 (Suppl. 10). 433 (2005)

    Google Scholar 

  21. Jambon, A., Weber, H. & Braun, O. Solubility of He, Ne, Ar, Kr, and Xe in a basalt melt in the range 1250–1600 °C. Geochemical implications. Geochim. Cosmochim. Acta 50, 401–408 (1986)

    ADS  CAS  Article  Google Scholar 

  22. Cartigny, P., Pineau, F., Aubaud, C. & Javoy, M. Towards a consistent mantle carbon flux estimate; insights from volatile systematics (H2O/Ce, δD, CO2/Nb) in the North Atlantic mantle (14° N and 34° N). Earth Planet. Sci. Lett. 265, 672–685 (2008)

    ADS  CAS  Article  Google Scholar 

  23. Saal, A., Hauri, E. H., Langmuir, C. H. & Perfit, M. Vapor undersaturation in primitive mid-ocean ridge basalt and the volatile content of the Earth’s upper mantle. Nature 419, 451–455 (2002)

    ADS  CAS  Article  Google Scholar 

  24. Genge, M. J., Jones, A. P. & Price, G. D. An infrared and Raman study of carbonate glasses: implications for the structure of carbonatite magmas. Geochim. Cosmochim. Acta 59, 927–937 (1995)

    ADS  CAS  Article  Google Scholar 

  25. Holland, G. & Ballentine, C. J. Seawater subduction controls the heavy noble gas composition of the mantle. Nature 441, 186–191 (2006)

    ADS  CAS  Article  Google Scholar 

  26. Pepin, R. O. & Porcelli, D. Xenon isotope systematics, giant impacts, and mantle degassing on the early Earth. Earth Planet. Sci. Lett. 250, 470–485 (2006)

    ADS  CAS  Article  Google Scholar 

  27. Peeters, F. et al. Improving noble gas based paleoclimate reconstruction and groundwater dating using 20Ne/22Ne ratios. Geochim. Cosmochim. Acta 67, 587–600 (2002)

    ADS  Article  Google Scholar 

  28. Sano, Y. & Marty, B. Origin of carbon in fumarolic gas from island arcs. Chem. Geol. 119, 265–274 (1995)

    ADS  CAS  Article  Google Scholar 

  29. Burnard, P. The bubble-by-bubble volatile evolution of two mid-ocean ridge basalts. Earth Planet. Sci. Lett. 174, 199–211 (1999)

    ADS  CAS  Article  Google Scholar 

  30. Porcelli, D. & Ballentine, C. J. in Noble Gases in Geochemistry and Cosmochemistry (eds Porcelli, D., Ballentine, C. & Wieler, R.) 412–480 (Rev. Mineral. Geochem. Vol. 47, Mineralogical Society of America, 2002)

    Book  Google Scholar 

  31. Newell, D. L., Crossey, L. J., Karlstrom, K. E., Fischer, T. P. & Hilton, D. R. Continental-scale links between the mantle and groundwater systems of the Western US: evidence from travertine springs and regional He isotope data. GSA Today 15, 4–10 (2005)

    Article  Google Scholar 

  32. Giggenbach, W. F. in Monitoring and Mitigation of Volcano Hazards (eds Scarpa, R. & Tilling, R.) 221–256 (Springer, 1996)

    Book  Google Scholar 

  33. Dixon, J. E., Stolper, E. M. & Holloway, J. R. An experimental study of water and carbon dioxide in mid-ocean ridge basaltic liquids. Part I: Calibration and solubility models. J. Petrol. 36, 1607–1631 (1995)

    CAS  Google Scholar 

Download references

Acknowledgements

We would like to thank CNRS-INSU for financial support, the French Embassy in Dar Es Salaam and The University of New Mexico Research Allocation Committee for support of field work, the US National Science Foundation for analytical support at the Scripps Institution of Oceanography (EAR-0439122) and the University of New Mexico (EAR-0537618, EAR- 0827352). We thank the Tanzania Commission for Science and Technology for granting research permission (2005-217-NA-2005-74) for this study. We thank C. Ballentine for a thorough review that greatly helped to improve this paper.

Author Contributions T.P.F. collected gas samples for chemical and isotopic analyses and analysed gas chemistry and N isotopes; P.B. and B.M. designed the study, led the field expedition to Oldoinyo Lengai and obtained funding for the expedition and permits; D.R.H. led the analysis of He, Ar and C isotopes and CO2/3He ratios; T.P.F., P.B., B.M. and D.R.H. collectively wrote the paper; E.F. analysed noble gases and C isotopes at the Scripps Institution of Oceanography; F.P. helped with sample collection; Z.D.S. supported N isotope analyses at the University of New Mexico; and F.M. helped with logistics in Tanzania, organizing the field expedition and obtaining permits.

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Fischer, T., Burnard, P., Marty, B. et al. Upper-mantle volatile chemistry at Oldoinyo Lengai volcano and the origin of carbonatites. Nature 459, 77–80 (2009). https://doi.org/10.1038/nature07977

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