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Annealing experiments on CO2-bearing jadeite glass: an insight into the true temperature dependence of CO2 speciation in silicate melts

Published online by Cambridge University Press:  05 July 2018

Y. Morizet ,
S. C. Kohn  and
R. A. Brooker
Y. Morizet
Affiliation:
Department of Earth Sciences, Wills Memorial Building, University of Bristol, Queen's Rd., Bristol BS8 1RJ, UK
S. C. Kohn*
Affiliation:
Department of Earth Sciences, Wills Memorial Building, University of Bristol, Queen's Rd., Bristol BS8 1RJ, UK
R. A. Brooker
Affiliation:
Department of Earth Sciences, Wills Memorial Building, University of Bristol, Queen's Rd., Bristol BS8 1RJ, UK
*
*E-mail: [email protected]
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Abstract

The thermodynamics and kinetics of CO2 speciation in silicate melts have been studied by measuring the concentration of CO2mol and carbonate in jadeite glass annealed at 575, 450 and 400°C. Assuming that the reaction is

1

where CO2mol..Obr represents a CO2 molecule weakly bonded to a bridging oxygen in the network and CO3 represents a bridging carbonate group with no net negative charge, ΔH for the reaction is –17 (+4/–8) kJ mol−1 and ΔS is –24 (+6/–9) J K−1 mol−1. The rate of equilibration of the species was measured at each temperature and the rate constants were deduced. The temperature dependence of the rate constants was used to determine the activation energy of the forward and reverse reactions which are 68 (+3/–31) kJ mol−1 and 86 (+1/–69) kJ mol−1 respectively. The data suggest that CO2mol may be much more abundant in silicate melts than previously assumed on the basis of studies of CO2-bearing glasses. Models of solubility, diffusion, and isotope fractionation should take this into account.

Keywords

jadeite glasssilicate meltsCO2 speciationannealing experiments
Type
Research Article
Information
Mineralogical Magazine , Volume 65 , Issue 6 , December 2001 , pp. 701 - 707
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2001

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References

Blank, J.G. and Brooker, R.A. (1994) Experimental studies of carbon dioxide in silicate melts: solubility, speciation and stable isotope behavior. Pp. 157-86 in: Volatiles in Magmas (Carroll, M.R. and Holloway, J.R., editors). Reviews in Mineralogy, 30. Mineralogical Society of America, Washington, D.C. CrossRefGoogle Scholar
Brey, G.P. (1976) CO2 solubility and solubility mechanisms in silicate melts at high pressures. Contrib. Mineral. Petrol., 57, 215–21.CrossRefGoogle Scholar
Brooker, R.A., Holloway, J.R. and Hervig, R.L. (1998) Reduction in piston cylinder experiments: Detection of carbon in. ltration into platinum capsules. Amer. Mineral., 83, 985–94.CrossRefGoogle Scholar
Brooker, R.A., Kohn, S.C., Holloway, J.R., McMillan, P.F. and Carroll, M.R. (1999) Solubility, speciation and dissolution mechanisms for CO2 in melts on the NaAlO2-SiO2 join. Geochim. Cosmochim. Acta, 63, 3549–65.CrossRefGoogle Scholar
Brooker, R.A., Kohn, S.C., Holloway, J.R. and McMillan, P.F. (2001 a) Structural controls on the solubility of CO2 in silicate melts. Part I: Bulk solubility data. Chem. Geol., 174, 225–40.CrossRefGoogle Scholar
Brooker, R.A., Kohn, S.C., Holloway, J.R. and McMillan, P.F. (2001 b) Structural controls on the solubility of CO2 in silicate melts. Part II: IR characteristics of carbonate groups in silicate glasses. Chem. Geol., 174, 241–54.CrossRefGoogle Scholar
Dingwell, D.B. and Webb, S.L. (1990) Relaxation in silicate melts. Eur. J. Mineral., 2, 427–49.CrossRefGoogle Scholar
Dixon, J.E., Stolper, E.M. and Holloway, J.R. (1995) An experimental study of water and carbon dioxide solubilities in mid-ocean ridge basaltic liquids. Part I: Calibration and solubility models. J. Petrol., 36, 1607–31.Google Scholar
Fine, G. and Stolper, E. (1985) The speciation of carbon dioxide in sodium aluminosilicate glasses. Contrib. Mineral. Petrol., 91, 105–21.CrossRefGoogle Scholar
Fine, G. and Stolper, E. (1986) Dissolved carbon dioxide in basaltic glasses: concentrations and speciation. Earth Planet. Sci. Lett., 76, 263–78.CrossRefGoogle Scholar
Fogel, R.A. and Rutherford, M.J. (1990) The solubility of carbon dioxide in rhyolitic melts: A quantitative FTIR study. Amer. Mineral., 75, 1311–26.Google Scholar
Holloway, J.R. and Blank, J.G. (1994) Application of experimental results to C-O-H species in natural melts. Pp. 187–230 in: Volatiles in Magmas (Carroll, M.R. and Holloway, J.R., editors). Reviews in Mineralogy, 30. Mineralogical Society of America, Washington, D.C. CrossRefGoogle Scholar
Kohn, S.C. (2000) The dissolution mechanisms of water in silicate melts; a synthesis of recent data. Mineral. Mag., 64, 389–408.CrossRefGoogle Scholar
Kohn, S.C., Brooker, R.A. and Dupree, R. (1991) 13C MAS NMR: A method for studying CO2 speciation in glasses. Geochim. Cosmochim. Acta, 55, 3879–84.CrossRefGoogle Scholar
Kubicki, J.D. and Stolper, E.M. (1995) Structural roles of CO2 and {CO3}2− in fully-polymerized, sodium aluminosilicate melts and glasses. Geochim. Cosmochim. Acta, 59, 683–98.CrossRefGoogle Scholar
Lange, R.A. (1994) The effects of H2O, CO2 and F on the density and viscosity of silicate melts. Pp. 331-69 in: Volatiles in Magmas (Carroll, M.R. and Holloway, J.R., editors). Reviews in Mineralogy, 30. Mineralogical Society of America, Washington, D.C. CrossRefGoogle Scholar
Morizet, Y., Brooker, R.A. and Kohn, S.C. (2001) CO2 in haplo-phonolitic melt: solubility, speciation and carbonate complexation. Geochim. Cosmochim. Acta (in press).CrossRefGoogle Scholar
Nowak, M. and Behrens, H. (1995) The speciation of water in haplogranitic glasses and melts determined by in-situ near-infrared spectroscopy. Geochim. Cosmochim. Acta, 59, 3445–50.CrossRefGoogle Scholar
Shen, A. and Keppler, H. (1995) Infrared-spectroscopy of hydrous silicate melts to 1000°C and 10 kbar – direct observation of H2O speciation in a diamondanvil cell. Amer. Mineral., 80, 1335–8.CrossRefGoogle Scholar
Stolper, E., Fine, G., Johnson, T. and Newman, S. (1987) Solubility of carbon dioxide in albitic melt. Amer. Mineral., 72, 1071–85.Google Scholar
Thibault, Y. and Holloway, J.R. (1994) Solubility of CO2 in a Ca-rich leucitite: Effects of pressure, temperature, and oxygen fugacity. Contrib. Mineral. Petrol. 116, 216–24.CrossRefGoogle Scholar
Watson, E.B. (1994) Diffusion in volatile-bearing magmas. Pp. 371–411 in: Volatiles in Magmas (Carroll, M.R. and Holloway, J.R., editors). Reviews in Mineralogy, 30. Mineralogical Society of America, Washington, D.C. CrossRefGoogle Scholar
Zhang, Y.X., Stolper, E.M. and Ihinger, P.D. (1995) Kinetics of the reaction H2O+O=2OH in rhyolitic and albitic glasses: preliminary results. Amer. Mineral., 80, 593–612.CrossRefGoogle Scholar