Abstract
The onset of partial melting beneath mid-ocean ridges governs the cycling of highly incompatible elements from the mantle to the crust1, the flux of key volatiles (such as CO2, He and Ar)1,2 and the rheological properties of the upper mantle3. Geophysical observations4,5,6 indicate that melting beneath ridges begins at depths approaching 300 km, but the cause of this melting has remained unclear. Here we determine the solidus of carbonated peridotite from 3 to 10 GPa and demonstrate that melting beneath ridges may occur at depths up to 330 km, producing 0.03–0.3% carbonatite liquid. We argue that these melts promote recrystallization and realignment of the mineral matrix, which may explain the geophysical observations. Extraction of incipient carbonatite melts from deep within the oceanic mantle produces an abundant source of metasomatic fluids and a vast mantle residue depleted in highly incompatible elements and fractionated in key parent-daughter elements. We infer that carbon, helium, argon and highly incompatible heat-producing elements (such as uranium, thorium and potassium) are efficiently scavenged from depths of ∼200–330 km in the upper mantle.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Plank, T. & Langmuir, C. H. Effects of melting regime on the composition of the oceanic crust. J. Geophys. Res. 97, 19749–19770 (1992)
Galer, S. J. G. & O'Nions, R. K. Magmagenesis and the mapping of chemical and isotopic variations in the mantle. Chem. Geol. 56, 45–61 (1986)
Karato, S.-I. & Jung, H. Water, partial melting and the origin of the seismic low velocity and high attenuation zone in the upper mantle. Earth Planet. Sci. Lett. 157, 193–207 (1998)
The MELT Seismic Team. Imaging the deep seismic structure beneath a mid-ocean ridge: the MELT experiment. Science 280, 1215–1218 (1998)
Evans, R. L. et al. Asymmetric electrical structure in the mantle beneath East Pacific Rise at 17 °S. Science 286, 752–756 (1999)
Gu, Y. J., Lerner-Lam, A. L., Dziewonski, A. M. & Ekstrom, G. Deep structure and seismic anisotropy beneath the East Pacific Rise. Earth Planet. Sci. Lett. 232, 259–272 (2005)
Sleep, N. H. & Zahnle, K. Carbon dioxide cycling and implications for climate on ancient Earth. J. Geophys. Res. 106, 1373–1399 (2001)
Zhang, Y. & Zindler, A. Distribution and evolution of carbon and nitrogen in Earth. Earth Planet. Sci. Lett. 117, 331–345 (1993)
Hirschmann, M. M. The mantle solidus: experimental constraints and the effect of peridotite composition. Geochem. Geophys. Geosyst. 1, 2000GC000070 (2000)
McKenzie, D. The extraction of magma from the crust and mantle. Earth Planet. Sci. Lett. 74, 81–91 (1985)
Yasuda, A., Fujii, T. & Kurita, K. Melting phase relations of anhydrous mid-ocean ridge basalt from 3 to 20 GPa: implications for the behavior of subducted oceanic crust in the mantle. J. Geophys. Res. 99, 9401–9414 (1994)
Kogiso, T., Hirschmann, M. M. & Frost, D. J. High-pressure melting of garnet-pyroxenite: possible mafic lithologies in the source of ocean island basalts. Earth Planet. Sci. Lett. 216, 603–617 (2003)
Aubaud, C., Hauri, E. H. & Hirschmann, M. M. Hydrogen partition coefficients between nominally anhydrous minerals and basaltic melts. Geophys. Res. Lett. 31, L20611, doi:10.1029/2004GL021341 (2004)
Wyllie, P. J. & Huang, W.-L. Influence of mantle CO2 in the generation of carbonatites and kimberlites. Nature 257, 297–299 (1975)
Eggler, D. H. Does CO2 cause partial melting in the low-velocity layer of the mantle? Geology 4, 69–72 (1976)
Dalton, J. A. & Presnall, D. C. Carbonatitic melts along the solidus of model lherzolite in the system CaO-MgO-Al2O3-SiO2-CO2 from 3 to 7 GPa. Contrib. Mineral. Petrol. 131, 123–135 (1998)
Presnall, D. C. & Gudfinnsson, G. H. in Plates, Plumes, and Paradigms (eds Foulger, G. R., Natland, J. H., Presnall, D. C. & Anderson, D. L.) 207–216 (Special Paper 388, Geological Society of America, Boulder, 2005)
Canil, D. & Scarfe, C. M. Phase relations in peridotite + CO2 systems to 12 GPa: implications for the origin of kimberlite and carbonate stability in the Earth's upper mantle. J. Geophys. Res. 95, 15805–15816 (1990)
Dasgupta, R., Hirschmann, M. M. & Dellas, N. The effect of bulk composition on the solidus of carbonated eclogite from partial melting experiments at 3 GPa. Contrib. Mineral. Petrol. 149, 288–305 (2005)
Falloon, T. J. & Green, D. H. The solidus of carbonated fertile peridotite. Earth Planet. Sci. Lett. 94, 364–370 (1989)
Wallace, M. E. & Green, D. H. An experimental determination of primary carbonatite magma composition. Nature 335, 343–346 (1988)
Wood, B. J., Pawley, A. & Frost, D. R. Water and carbon in the Earth's mantle. Phil. Trans. R. Soc. Lond. 354, 1495–1511 (1996)
Frost, D. J. & Wood, B. J. Experimental measurements of the fugacity of CO2 and graphite/diamond stability from 35 to 77 kbar at 925 to 1650 °C. Geochim. Cosmochim. Acta 61, 1565–1574 (1997)
Hammouda, T. & Laporte, D. Ultrafast mantle impregnation by carbonatite melts. Geology 28, 283–285 (2000)
Holtzman, B. K. et al. Melt segregation and strain partitioning: Implications for seismic anisotropy and mantle flow. Science 301, 1227–1230 (2003)
Minarik, W. G. & Watson, E. B. Interconnectivity of carbonate melt at low melt fraction. Earth Planet. Sci. Lett. 133, 423–437 (1995)
Rabinowicz, M., Ricard, Y. & Grégoire, M. Compaction in a mantle with a very small melt concentration: implications for the generation of carbonatitic and carbonate-bearing high alkaline mafic melt impregnations. Earth Planet. Sci. Lett. 203, 205–220 (2002)
Javoy, M. & Pineau, F. The volatiles record of a 'popping' rock from the Mid-Atlantic Ridge at 14°N: chemical and isotopic composition of gas trapped in the vesicles. Earth Planet. Sci. Lett. 107, 598–611 (1991)
Marty, B. & Tolstikhin, I. N. CO2 fluxes from mid-ocean ridges, arcs, and plumes. Chem. Geol. 145, 233–248 (1998)
Ita, J. & Stixrude, L. Petrology, elasticity, and composition of the mantle transition zone. J. Geophys. Res. 97, 6849–6866 (1992)
McKenzie, D., Jackson, J. & Priestley, K. Thermal structure of oceanic and continental lithosphere. Earth Planet. Sci. Lett. 233, 337–349 (2005)
Keppler, H., Wiedenbeck, M. & Shcheka, S. S. Carbon solubility in olivine and the mode of carbon storage in the Earth's mantle. Nature 424, 414–416 (2003)
Bézos, A. & Humler, E. The Fe3+/ΣFe ratios of MORB glasses and their implications for mantle melting. Geochim. Cosmochim. Acta 69, 711–725 (2005)
Acknowledgements
We thank A. C. Withers and C. Aubaud for comments on the manuscript, P. Asimow for conversations and N. Smith for help with the piston cylinder experiments. This work is supported by NSF.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Competing interests
Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.
Supplementary information
Supplementary Notes
This file contains the Supplementary Methods, Supplementary Figure 1, Supplementary Tables 1–4 and additional references. (PDF 236 kb)
Rights and permissions
About this article
Cite this article
Dasgupta, R., Hirschmann, M. Melting in the Earth's deep upper mantle caused by carbon dioxide. Nature 440, 659–662 (2006). https://doi.org/10.1038/nature04612
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/nature04612
Comments
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.