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.

Carbon dioxide released from subduction zones by fluid-mediated reactions


The balance between the subduction of carbonate mineral-bearing rocks into Earth’s mantle and the return of CO2 to the atmosphere by volcanic and metamorphic degassing1,2,3,4 is critical to the carbon cycle. Carbon is thought to be released from subducted rocks mostly by simple devolatilization reactions5,6,7. However, these reactions will also retain large amounts of carbon within the subducting slab and have difficulty in accounting for the mass of CO2 emitted from volcanic arcs. Carbon release may therefore occur via fluid-induced dissolution of calcium carbonate8,9,10. Here we use carbonate δ18O and δ13C systematics, combined with analyses of rock and fluid inclusion mineralogy and geochemistry, to investigate the alteration of the exhumed Eocene Cycladic subduction complex on the Syros and Tinos islands, Greece. We find that in marble rocks adjacent to two fluid conduits that were active during subduction, the abundance of calcium carbonate drastically decreases approaching the conduits, whereas silicate minerals increase. Up to 60–90% of the CO2 was released from the rocks—far greater than expected via simple devolatilization reactions. The δ18O of the carbonate minerals is 5–10 lighter than is typical for metamorphosed carbonate rocks, implying that isotopically light oxygen was transported by fluid infiltration from the surroundings. We suggest that fluid-mediated carbonate mineral removal, accompanied by silicate mineral precipitation, provides a mechanism for the release of enormous amounts of CO2 from subduction zones.

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

Get just this article for as long as you need it


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

Figure 1: Examples of highly reacted metacarbonate rocks.
Figure 2: Petrography and fluid inclusions, Profiles 1 (left) and 2 (right).
Figure 3: Chemical and isotopic profiles.
Figure 4: Cartoons illustrating geological settings of carbonate reaction.


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

    Article  Google Scholar 

  2. Hayes, J. M. & Waldbauer, J. R. The carbon cycle and associated redox processes through time. Phil. Trans. R. Soc. B 361, 931–950 (2006).

    Article  Google Scholar 

  3. Dasgupta, R. & Hirschmann, M. M. The deep carbon cycle and melting in Earth’s interior. Earth Planet. Sci. Lett. 298, 1–13 (2010).

    Article  Google Scholar 

  4. Burton, M. R., Sawyer, G. M. & Granieri, D. Deep carbon emissions from volcanoes. Rev. Mineral. Geochem. 75, 323–354 (2013).

    Article  Google Scholar 

  5. Kerrick, D. M. & Connolly, J. A. D. Metamorphic devolatilization of subducted marine sediments and the transport of volatiles into the Earth’s mantle. Nature 411, 293–296 (2001).

    Article  Google Scholar 

  6. Gorman, P. J., Kerrick, D. M. & Connolly, J. A. D. Modeling open system metamorphic decarbonation of subducting slabs. Geochem. Geophys. Geosyst. 7, Q04007 (2006).

    Article  Google Scholar 

  7. Poli, S., Franzolin, E., Fumagalli, P. & Crottini, A. The transport of carbon and hydrogen in subducted oceanic crust: An experimental study to 5 GPa. Earth Planet. Sci. Lett. 278, 350–360 (2009).

    Article  Google Scholar 

  8. Frezzotti, M. L., Selverstone, J., Sharp, Z. D. & Compagnoni, R. Carbonate dissolution during subduction revealed by diamond-bearing rocks from the Alps. Nature Geosci. 4, 703–706 (2011).

    Article  Google Scholar 

  9. Pan, D., Spanu, L., Harrison, B., Sverjensky, D. A. & Galli, G. Dielectric properties of water under extreme conditions and transport of carbonates in the deep Earth. Proc. Natl Acad. Sci. USA 110, 6646–6650 (2013).

    Article  Google Scholar 

  10. Manning, C. E., Shock, E. L. & Sverjensky, D. A. The chemistry of carbon in aqueous fluids at crustal and upper-mantle conditions: Experimental and theoretical constraints. Rev. Mineral. Geochem. 75, 109–148 (2013).

    Article  Google Scholar 

  11. Connolly, J. A. D. Computation of phase equilibria by linear programming: A tool for geodynamic modeling and its application to subduction zone decarbonation. Earth Planet. Sci. Lett. 236, 524–541 (2005).

    Article  Google Scholar 

  12. Manning, C. E. Thermodynamic modeling of fluid-rock interaction at mid-crustal to upper-mantle conditions. Rev. Mineral. Geochem. 76, 135–164 (2013).

    Article  Google Scholar 

  13. Bröcker, M. & Franz, L. Rb–Sr isotope studies on Tinos Island (Cyclades, Greece): Additional time constraints for metamorphism, extent of infiltration-controlled overprinting and deformational activity. Geol. Mag. 135, 369–382 (1998).

    Article  Google Scholar 

  14. Marschall, H. R., Altherr, R., Gméling, K. & Kasztovszky, Z. Lithium, boron and chlorine as tracers for metasomatism in high-pressure metamorphic rocks: A case study from Syros (Greece). Min. Petrol. 95, 291–302 (2009).

    Article  Google Scholar 

  15. Dragovic, B., Samanta, L. M., Baxter, E. F. & Selverstone, J. Using garnet to constrain the duration and rate of water-releasing metamorphic reactions during subduction: An example from Sifnos, Greece. Chem. Geol. 314–317, 9–22 (2012).

    Article  Google Scholar 

  16. Trotet, F., Vidal, O. & Jolivet, L. Exhumation of Syros and Sifnos metamorphic rocks (Cyclades, Greece) New constraints on the P–T paths. Eur. J. Mineral. 13, 901–920 (2001).

    Article  Google Scholar 

  17. Miller, D. P., Marschall, H. R. & Schumacher, J. C. Metasomatic formation and petrology of blueschist-facies hybrid rocks from Syros (Greece): Implications for reactions at the slab–mantle interface. Lithos 107, 53–67 (2009).

    Article  Google Scholar 

  18. Ague, J. J. Extreme channelization of fluid and the problem of element mobility during Barrovian metamorphism. Am. Mineral 96, 333–352 (2011).

    Article  Google Scholar 

  19. Syracuse, E. M., van Keken, P. E. & Abers, G. A. The global range of subduction zone thermal models. Phys. Earth Planet. Inter. 183, 73–90 (2010).

    Article  Google Scholar 

  20. Bickle, M. J. Transport mechanisms by fluid flow in metamorphic rocks: Oxygen and strontium decoupling in the Trois Seigneurs Massif—a consequence of kinetic dispersion? Am. J. Sci. 292, 289–316 (1992).

    Article  Google Scholar 

  21. Tracy, R. J., Rye, D. M., Hewitt, D. A. & Schiffries, C. M. Petrologic and stable-isotopic studies of fluid-rock interactions, south-central Connecticut: I. the role of infiltration in producing reaction assemblages in impure marbles. Am. J. Sci. 283A, 589–616 (1983).

    Google Scholar 

  22. Putnis, A. & John, T. Replacement processes in the Earth’s crust. Elements 6, 159–164 (2010).

    Article  Google Scholar 

  23. Breeding, C. M., Ague, J. J. & Bröcker, M. Fluid–metasedimentary rock interactions in subduction-zone mélange: Implications for the chemical composition of arc magmas the chemical composition of arc magmas. Geology 32, 1041–1044 (2004).

    Article  Google Scholar 

  24. De Capitani, C. & Petrakakis, K. The computation of equilibrium assemblage diagrams with Theriak/Domino software. Am. Mineral. 95, 1006–1016 (2010).

    Article  Google Scholar 

  25. Holland, T. J. B. & Powell, R. An internally consistent data set for phases of petrological interest. J. Metam. Geol. 16, 309–343 (1998).

    Article  Google Scholar 

  26. Rea, D. K. & Ruff, L. J. Composition and mass flux of sediment entering the world’s subduction zones: Implications for global sediment budgets, great earthquakes, and volcanism. Earth Planet. Sci. Lett. 140, 1–12 (1996).

    Article  Google Scholar 

  27. Plank, T. & Langmuir, C. H. The chemical composition of subducting sediment and its consequences for the crust and mantle. Chem. Geol. 145, 325–394 (1998).

    Article  Google Scholar 

  28. Johnston, F. K. B., Turchyn, A. V. & Edmonds, M. Decarbonation efficiency in subduction zones: Implications for warm Cretaceous climates. Earth Planet. Sci. Lett. 303, 143–152 (2011).

    Article  Google Scholar 

  29. Bebout, G. E. & Barton, M. D. Tectonic and metasomatic mixing in a high-T, subduction-zone mélange—insights into the geochemical evolution of the slab–mantle interface. Chem. Geol. 187, 79–106 (2002).

    Article  Google Scholar 

  30. Penniston-Dorland, S. C., Sorensen, S. S., Ash, R. D. & Khadke, S. V. Lithium isotopes as a tracer of fluids in a subduction zone mélange: Franciscan Complex, CA. Earth. Planet. Sci. Lett. 292, 181–190 (2010).

    Article  Google Scholar 

Download references


We thank C. M. Breeding, M. Bröcker, E. L. Donald and D. E. Wilbur for discussions and field work; M. E. Galvez for perspectives on fluid inclusions; R. A. Berner, O. Beyssac, C. P. Chamberlain, B. Marty and D. Rumble for insights regarding carbon cycling; G. W. Olack for assistance with the stable isotope analyses; J. O. Eckert, Jr, for assistance with the FEG-EPMA; and H. Marschall for insightful comments. J.J.A. thanks the Reservoirs and Fluxes Community of the Deep Carbon Observatory for supporting a workshop on Tectonic Fluxes of Carbon. Funding provided by the US National Science Foundation Directorate of Geosciences (EAR-0105927, EAR-0744154) is gratefully acknowledged.

Author information

Authors and Affiliations



Bulk chemical, stable isotope, and pseudosection analyses were done by J.J.A., petrography was done by J.J.A. and S.N., and fluid inclusion investigation was done by S.N. and J.J.A. Both authors extensively discussed and prepared the manuscript.

Corresponding author

Correspondence to Jay J. Ague.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 5218 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Ague, J., Nicolescu, S. Carbon dioxide released from subduction zones by fluid-mediated reactions. Nature Geosci 7, 355–360 (2014).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


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