Remember Me
Or use your Academic/Social account:


Or use your Academic/Social account:


You have just completed your registration at OpenAire.

Before you can login to the site, you will need to activate your account. An e-mail will be sent to you with the proper instructions.


Please note that this site is currently undergoing Beta testing.
Any new content you create is not guaranteed to be present to the final version of the site upon release.

Thank you for your patience,
OpenAire Dev Team.

Close This Message


Verify Password:
Verify E-mail:
*All Fields Are Required.
Please Verify You Are Human:
fbtwitterlinkedinvimeoflicker grey 14rssslideshare1
Shorttle, Oliver; Moussallam, Yves; Hartley, Margaret E.; Maclennan, John; Edmonds, Marie; Murton, Bramley J.
Publisher: Earth and Planetary Science Letters
Languages: English
Types: Unknown
Subjects: Space and Planetary Science, Mantle heterogeneity, pyroxenite, Earth and Planetary Sciences (miscellaneous), Geophysics, sub-05, Marine Sciences, XANES, Oxygen, Geochemistry and Petrology, mantle fO2, Mantle fO₂
The cycling of material from Earth’s surface environment into its interior can couple mantle oxidation state to the evolution of the oceans and atmosphere. A major uncertainty in this exchange is whether altered oceanic crust entering subduction zones can carry the oxidised signal it inherits during alteration at the ridge axis, past the arc front and into the deep mantle for long-term storage. However, recycled oceanic crust may eventually be entrained into mantle upwellings and undergo melting at ocean islands, creating the potential for basalt chemistry to constrain the nature of past solid Earth–hydrosphere redox coupling.

Numerous independent observations suggest that Iceland contains a significant recycled oceanic crustal component, making it an ideal locality to investigate links between redox proxies and geochemical indices of enrichment. We have interrogated the elemental, isotope and redox geochemistry of basalts from the Reykjanes Ridge, which forms a 700 km transect of the Iceland plume. Over this distance, geophysical and geochemical tracers of plume influence increase dramatically, with the basalts recording both longand short-wavelength heterogeneity in the Iceland plume. We present new high-precision Fe-XANES measurements of Fe3+=P Fe on a suite of 64 basalt glasses from the Reykjanes Ridge. These basalts exhibit positive correlations between Fe3+=P Fe and trace element and isotopic signals of enrichment, and become progressively oxidised towards Iceland: fractionation-corrected Fe3+=P Fe increases by ? 0:015 and ?QFM by ? 0:2 log units. We carefully rule out a role for sulfur degassing in creating this trend, and by considering various redox melting processes and metasomatic source enrichment mechanisms, conclude that an intrinsically oxidised component within the Icelandic mantle is required. Given the previous evidence for entrained oceanic crustal material within the Iceland plume, we consider this the most plausible carrier of the oxidised signal.

To determine the ferric iron content of the recycled component ([Fe2O3]source[Fe2O3]source) we project observed liquid compositions to an estimate of Fe2O3 in the pure enriched endmember melt, and then apply simple fractional melting models, considering lherzolitic and pyroxenitic source mineralogies, to estimate [Fe2O3](source)[Fe2O3](source) content. Propagating uncertainty through these steps, we obtain a range of [Fe2O3](source)[Fe2O3](source) for the enriched melts (0.9–1.4 wt%) that is significantly greater than the ferric iron content of typical upper mantle lherzolites. This range of ferric iron contents is consistent with a hybridised lherzolite–basalt (pyroxenite) mantle component. The oxidised signal in enriched Icelandic basalts is therefore potential evidence for seafloor–hydrosphere interaction having oxidised ancient mid-ocean ridge crust, generating a return flux of oxygen into the deep mantle.
  • The results below are discovered through our pilot algorithms. Let us know how we are doing!

    • Ballhaus, C., Frost, B.R., 1994. The generation of oxidised CO2-bearing basaltic melts from reduced CH4-bearing upper mantle sources. Geochim. Cosmochim. Acta 58, 4931-4940.
    • Berry, A.J., O'Neill, H.S., Jayasuriya, K.D., Campbell, S.J., Foran, G.J., 2003. XANES calibrations for the oxidation state of iron in silicate glass. Am. Mineral. 88, 967-977.
    • Bézos, A., Humler, E., 2005. The Fe3+/ Fe ratios of MORB glasses and their implications for mantle melting. Geochim. Cosmochim. Acta 69, 711-725.
    • Burgisser, A., Scaillet, B., 2007. Redox evolution of a degassing magma rising to the surface. Nature 445, 194-197.
    • Canfield, D.E., Poulton, S.W., Narbonne, G.M., 2007. Late-Neoproterozoic deep-ocean oxygenation and the rise of animal life. Science 315, 92-95.
    • Canil, D., O'Neill, H.S.C., Pearson, D.G., Rudnick, R.L., McDonough, W.F., Carswell, D.A., 1994. Ferric iron in peridotites and mantle oxidation states. Earth Planet. Sci. Lett. 123, 205-220.
    • Carmichael, I.S.E., 1991. The redox states of basic and silicic magmas: a reflection of their source regions? Contrib. Mineral. Petrol. 106, 129-141.
    • Chase, C.G., 1981. Oceanic island Pb: two-stage histories and mantle evolution. Earth Planet. Sci. Lett. 52, 277-284.
    • Chauvel, C., Hémond, C., 2000. Melting of a complete section of recycled oceanic crust: trace element and Pb isotopic evidence from Iceland. Geochem. Geophys. Geosyst. 1.
    • Cottrell, E., Kelley, K.A., 2009. High-precision determination of iron oxidation state in silicate glasses using XANES. Chem. Geol. 268, 169-179.
    • Cottrell, E., Kelley, K.A., 2011. The oxidation state of Fe in MORB glasses and the oxygen fugacity of the upper mantle. Earth Planet. Sci. Lett. 305, 279-282.
    • Cottrell, E., Kelley, K.A., 2013. Redox heterogeneity in mid-ocean ridge basalts as a function of mantle source. Science 340, 1314-1317.
    • Danyushevsky, L.V., Plechov, P., 2011. Petrolog3: integrated software for modeling crystallization processes. Geochem. Geophys. Geosyst. 12.
    • Dixon, J.E., Clague, D.A., Stolper, E.M., 1991. Degassing history of water, sulfur, and carbon in submarine lavas from Kilauea volcano, Hawaii. J. Geol. 99, 371-394.
    • Farges, F., Lefrère, Y., Rossano, S., Berthereau, A., Calas, G., Brown Jr., G.E., 2004. The effect of redox state on the local structural environment of iron in silicate glasses: a combined XAFS spectroscopy, molecular dynamics, and bond valence study. J. Non-Cryst. Solids 344, 176-188.
    • Frost, B.R., 1991. An introduction to oxygen fugacity and its petrological importance. In: Lindsley, D.H. (Ed.), Oxide Minerals: Petrologic and Magnetic Significance. In: Rev. Mineral. Geochem., vol. 25. Mineralogical Society of America, Washington, DC, pp. 1-9.
    • Gaillard, F., Scaillet, B., Arndt, N.T., 2011. Atmospheric oxygenation caused by a change in volcanic degassing processes. Nature 478, 229-232.
    • Gibson, S.A., Geist, D., 2010. Geochemical and geophysical estimates of lithospheric thickness variation beneath Galápagos. Earth Planet. Sci. Lett. 300, 275-286.
    • Hémond, C., Hofmann, A.W., Vlastélic, I., Nauret, F., 2006. Origin of MORB enrichment and relative trace element compatibilities along the Mid-Atlantic Ridge between 10◦ and 24◦N. Geochem. Geophys. Geosyst. 7.
    • Herzberg, C., O'Hara, M.J., 2002. Plume-associated ultramafic magmas of Phanerozoic age. J. Petrol. 43, 1857-1883.
    • Table A.2
    • Covariance and correlation matrices for parameters in the PCR calibration: Fe3+/ Fe = a0 + a1PC1 + a2PC2.
    • Hilton, D.R., Thirlwall, M.F., Taylor, R.N., Murton, B.J., Nichols, A., 2000. Controls on the magmatic degassing along the Reykjanes Ridge with implications for the helium paradox. Earth Planet. Sci. Lett. 183, 43-50.
    • Jones, S.M., Murton, B.J., Fitton, J.G., White, N.J., Maclennan, J., Walters, R.L., 2014. A joint geochemical-geophysical record of time-dependent mantle convection south of Iceland. Earth Planet. Sci. Lett. 386, 86-97.
    • Jugo, P.J., 2009. Sulfur content at sulfide saturation in oxidized magmas. Geology 37, 415-418.
    • Kasting, J.F., 2013. What caused the rise of atmospheric O2. Chem. Geol. 362, 13-25.
    • Kelley, K.A., Cottrell, E., 2009. Water and the oxidation state of subduction zone magmas. Science 325, 605-607.
    • Kessel, R., Schmidt, M.W., Ulmer, P., Pettke, T., 2005. Trace element signature of subduction-zone fluids, melts and supercritical liquids at 120-180 km depth. Nature 437, 724-727.
    • Kogiso, T., Hirose, K., Takahashi, E., 1998. Melting experiments on homogeneous mixtures of peridotite and basalt: application to the genesis of ocean island basalts. Earth Planet. Sci. Lett. 162, 45-61.
    • Kress, V.C., Carmichael, I.S.E., 1991. The compressibility of silicate liquids containing Fe2O3 and the effect of composition, temperature, oxygen fugacity and pressure on their redox states. Contrib. Mineral. Petrol. 108, 82-92.
    • Lécuyer, C., Ricard, Y., 1999. Long-term fluxes and budget of ferric iron: implication for the redox states of the Earth's mantle and atmosphere. Earth Planet. Sci. Lett. 165, 197-211.
    • Liu, Y., Samaha, N.T., Baker, D.R., 2007. Sulfur concentration at sulfide saturation (SCSS) in magmatic silicate melts. Geochim. Cosmochim. Acta 71, 1783-1799.
    • Malherbe, J., Claverie, F., 2013. Toward chromium speciation in solids using wavelength dispersive X-ray fluorescence spectrometry Cr Kβ lines. Anal. Chim. Acta 773, 37-44.
    • Mallmann, G., O'Neill, H.S.C., 2009. The crystal/melt partitioning of V during mantle melting as a function of oxygen fugacity compared with some other elements (Al, P, Ca, Sc, Ti, Cr, Fe, Ga, Y, Zr and Nb). J. Petrol. 50, 1765-1794.
    • Manceau, A., Gorshkov, A.I., Drits, V.A., 1992. Structural chemistry of Mn, Fe, Co, and Ni in manganese hydrous oxides: Part I. Information from XANES spectroscopy. Am. Mineral. 77, 1133-1143.
    • McKenzie, D., Stracke, A., Blichert-Toft, J., Albaréde, F., Grönvold, K., O'Nions, R.K., 2004. Source enrichment processes responsible for isotopic anomalies in oceanic island basalts. Geochim. Cosmochim. Acta 68, 2699-2724.
    • Métrich, N., Berry, A.J., O'Neill, H.S., Susini, J., 2009. The oxidation state of sulfur in synthetic and natural glasses determined by X-ray absorption spectroscopy. Geochim. Cosmochim. Acta 73, 2382-2399.
    • Moussallam, Y., Oppenheimer, C., Scaillet, B., Gaillard, F., Kyle, P., Peters, N., Hartley, M., Berlo, K., Donovan, A., 2014. Tracking the changing oxidation state of Erebus magmas, from mantle to surface, driven by magma ascent and degassing. Earth Planet. Sci. Lett. 393, 200-209.
    • Murton, B.J., 1995. RSS Charles Darwin Cruise 80, 01 September to 01 October 1993. The PETROS programme: geologic sampling and bathymetric surveying of the Reykjanes Ridge between 57◦N and 63◦N, southwest of Iceland. Deacon Laboratory Cruise Report 236. Institute of Oceanographic Sciences.
    • Murton, B.J., Taylor, R.N., Thirlwall, M.N., 2002. Plume-ridge interaction: a geochemical perspective from the Reykjanes Ridge. J. Petrol. 43, 1987-2012.
    • Navin, D.A., Sinha, M.C., 1998. The RAMESSES experiment-II. Evidence for accumulated melt beneath a slow spreading ridge from wide-angle refraction and multichannel reflection seismic profiles. Geophys. J. Int. 135, 746-772.
    • Nichols, A.R.L., Carroll, M.R., Höskuldsson, A., 2002. Is the Iceland hot spot also wet? Evidence from the water contents of undegassed submarine and subglacial pillow basalts. Earth Planet. Sci. Lett. 202, 77-87.
    • O'Neill, H.S.C., Rubie, D.C., Canil, D., Geiger, C.A., Ross II, C.R., Seifert, F., Woodland, A.B., 1993. Ferric iron in the upper mantle and in transition zone assemblages: implications for relative oxygen fugacities in the mantle. In: Geophys. Monogr., vol. 74. American Geophysical Union, pp. 73-88.
    • Press, W.H., Teukolsky, S.A., Vetterling, W.T., Flannery, B.P., 1992. Numerical Recipes in C, second edition. Cambridge University Press.
    • R Core Team, 2013. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria.
    • Saal, A.E., Hauri, E., Langmuir, C.H., Perfit, M., 2002. Vapour undersaturation in primitive mid-ocean-ridge basalt and the volatile content of Earth's upper mantle. Nature 419, 451-455.
    • Schilling, J.G., 1973. Iceland mantle plume: geochemical study of Reykjanes ridge. Nature 242, 565-571.
    • Shorttle, O., Maclennan, J., 2011. Compositional trends of Icelandic basalts: implications for short-lengthscale lithological heterogeneity in mantle plumes. Geochem. Geophys. Geosyst. 12.
    • Shorttle, O., Maclennan, J., Jones, S.M., 2010. Control of the symmetry of plume ridge interaction by spreading-ridge geometry. Geochem. Geophys. Geosyst. 11.
    • Shorttle, O., Maclennan, J., Lambart, S., 2014. Quantifying lithological variability in the mantle. Earth Planet. Sci. Lett. 395, 24-40.
    • Sims, K.W.W., DePaolo, D.J., 1997. Inferences about mantle magma sources from incompatible element concentration ratios in oceanic basalts. Geochim. Cosmochim. Acta 61, 765-784.
    • Sims, K.W.W., Maclennan, J., Blichert-Toft, J., Mervine, E.M., Blusztajn, J., Gönvold, K., 2013. Short length scale mantle heterogeneity beneath Iceland probed by glacial modulation of melting. Earth Planet. Sci. Lett. 379, 146-157.
    • Sleep, N.H., 2005. Dioxygen over geologic time. Met. Ions Biol. Syst. 43, 49-73.
    • Smallwood, J.R., White, R.S., 1998. Crustal accretion at the Reykjanes Ridge, 61◦-62◦N. J. Geophys. Res. 103, 5185-5201.
    • Stagno, V., Ojwang, D.O., McCammon, C.A., Frost, D.J., 2013. The oxidation state of the mantle and the extraction of carbon from the Earth's interior. Nature 493, 84-88.
    • Stracke, A., 2012. Earth's heterogeneous mantle: a product of convection driven interaction between crust and mantle. Chem. Geol. 330-331, 274-299.
    • Stracke, A., Bizimis, M., Salters, V.J.M., 2003a. Recycling oceanic crust: quantitative constraints. Geochem. Geophys. Geosyst. 4.
    • Stracke, A., Zindler, A., Salters, V.J.M., McKenzie, D., Blichert-Toft, J., Albarède, F., Grönvold, K., 2003b. Theistareykir revisited. Geochem. Geophys. Geosyst. 4.
    • Thirlwall, M.F., Gee, M.A.M., Taylor, R.N., Murton, B.J., 2004. Mantle components in Iceland and adjacent ridges investigated using double-spike Pb isotope ratios. Geochim. Cosmochim. Acta 68, 361-386.
    • Vigneau, E., Devaux, M.F., Qannari, E.M., Robert, P., 1997. Principal component regression, ridge regression and ridge principal component regression in spectroscopy calibration. J. Chemom. 11, 239-249.
    • White, R.S., Bown, J.W., Smallwood, J.R., 1995. The temperature of the Iceland plume and origin of outward-propagating V-shaped ridges. J. Geol. Soc. (Lond.) 152, 1039-1045.
    • Wilke, M., Farges, F., Petit, P.E., Brown Jr., G.E., Martin, F., 2001. Oxidation state and coordination of Fe in minerals: an Fe K-XANES spectroscopic study. Am. Mineral. 86, 714-730.
    • Wilke, M., Jugo, P.J., Klimmm, K., Susini, J., Botcharnikov, R., Kohn, S.C., Janousch, M., 2008. The origin of S4+ detected in silicate glasses by XANES. Am. Mineral. 93, 235-240.
    • Wong, J., Lytle, F.W., Messmer, R.P., Maylotte, D.H., 1984. K-edge absorption spectra of selected vanadium compounds. Phys. Rev. B 30, 5596-5610.
    • York, D., 1969. Least squares fitting of a straight line with correlated errors. Earth Planet. Sci. Lett. 5, 320-324.
  • No related research data.
  • No similar publications.