Abstract
The rate of growth of fayalite (Fe2SiO4) has been measured at one atmosphere total pressure, temperatures from 1000° to 1120° C, and oxygen fugacities controlled by CO/CO2 gas-mixing from 10-9.9 to 10-13.0atm, chosen to span the fayalite stability field. The fine-grained polycrystalline fayalite layer was formed by reacting the oxides FeO or Fe3O4 with a thin slice of single-crystal quartz. The rate of growth of the fayalite increases with increasing temperature and decreasing oxygen fugacity, and is consistent with a parabolic rate law, indicating that the growth rate is controlled by diffusion through the fayalite. Microstructural observations and platinum marker experiments suggest that the reaction phase is formed at the quartz-fayalite interface, and is therefore controlled by the diffusion of iron and oxygen. The parabolic rate constant was analyzed in terms of the oxide activity gradient to yield mean chemical diffusivities for the rate-limiting ionic species, assuming bulk transport through the fayalite layer. Given that iron diffusion in olivine polycrystals occurs either by lattice diffusion, which shows a positive dependence on oxygen activity, or by grain boundary diffusion, which would result in growth rates significantly faster than we observe, we conclude that the diffusivities derived in this study represent oxygen diffusion. However, since oxygen lattice diffusion in fayalite has been established to be much slower than our measurements, it is likely that the transport path for oxygen is along the grain boundaries. Thus, the mean grain boundary diffusivity of oxygen in fayalite \(\bar D\) gbO (m2 s-1), using the measured grain size of 0.25 μm, is then given by
, where δ is the grain boundary width (in m), and the activation energy is in kJ/mol. Assuming δ=10-9 m (Ricoult and Kohlstedt 1983), the oxygen grain boundary diffusivities are about a factor of 30 × slower than those reported by Watson (1986) for Fo90 olivine.
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References
Atkinson A (1987) Grain boundary diffusion in oxides and its contribution to oxidation processes. In: Oxidation of metals and associated mass transport, Dayananda MA, Rothman SJ, King WE (eds). The Metallurgical Society, Inc., pp 29–47
Atkinson A, Taylor RI (1979) The diffusion of nickel in the bulk and along dislocations in NiO single crystals. Philos Mag 39:581–595
Atkinson A, Taylor RI (1981) The diffusion of 63Ni along grain boundaries in nickel oxide. Philos Mag 43:979–998
Atkinson A, Taylor RI (1982) The diffusion of 57Co along grain boundaries in nickel oxide. Philos Mag 45:583–592
Atkinson A, Taylor RI (1985) Diffusion of 55Fe in Fe2O3 single crystals. J Phys Chem Solids 46:469–475
Becker KD, Dreher S, Wißmann (1992) A high-temperature Mössbauer study of fayalite, Fe2SiO4: Cation diffusion and reactivity. Ber Bunsenges Phys Chem 96:1778–1783
Borchardt G, Jaoul O, Scherrer S (1979) Formazione di silicati mediante reazioni allo stato solido ad alta temperatura. La Ceram Nov–Dec:7–22
Brady JB (1983) Intergranular diffusion in metamorphic rocks. Am J Sci 283A: 181–200
Buening DK, Buseck PR (1973) Fe-Mg lattice diffusion in olivine. J Geophys Res 78:6852–6862
Farver JR, Yund RA (1991) Measurement of oxygen grain boundary diffusion in natural, fine-grained, quartz aggregates. Geochim Cosmochim Acta 55:1597–1607
Gerard O, Jaoul O (1989) Oxygen diffusion in San Carlos olivine. J Geophys Res 94:4119–4128
Hermeling J, Schmalzried H (1984) Tracerdiffusion of the Fe-cations in olivine (FexMg1-x)2SiO4(III). Phys Chem Minerals 11:161–166
Houlier B, Jaoul O, Abel F, Liebermann RC (1988) Oxygen and silicon self-diffusion in natural olivine at 1300° C. Phys Earth Planet Ints 50:240–250
Houlier B, Cheraghmakani M, Jaoul O (1990) Silicon diffusion in San Carlos olivine. Phys Earth Planet Ints 62:329–340
Jaoul O, Froidevaux C, Durham WB, Michaut M (1980) Oxygen self-diffusion in forsterite: Implications for the high-temperature creep mechanism. Earth Planet Sci Lett 47:391–397
Jaoul O, Houlier B (1983) Study of 18O diffusion in magnesium orthosilicate by nuclear microanalysis. J Geophys Res 88:631–624
Jaoul O, Poumellec M, Froidevaux C, Havette A (1981) Silicon diffusion in forsterite: A new constraint for understanding mantle deformation. In: Anelasticity in the earth; geodynamic series; volume 4, Stacey FD, Paterson MS, Nicholas A (eds). Am Geophys Union, Washington DC, pp 95–100
Jurewicz AJG, Watson EB (1988) Cations in olivine, Part 2: Diffusion in olivine xenocrysts, with applications to petrology and mineral physics. Contrib Mineral Petrol 99: 186–201
Kroger FA, Vink HJ (1956) Relations between the concentrations of imperfections in crystalline solids. In: Solid State Physics, Vol 3, Seitz F, Turnball D (eds). Acad Press, New York, pp 307–435
Misener DJ (1972) Interdiffusion studies in the system Fe2SiO4 -Mg2SiO4. Ann Rep Geophys Lab Yearb 71:54–56
Misener DJ (1974) Cationic diffusion in olivine to 1400° C and 35 kbar. In Geochemical Transport and Kinetics, eds Hofmann AW, Giletti BJ, Yoder HS, Yund RA, pp 117–129. Carnegie Inst Wash 634
Nakamura A, Schmalzried H (1984) On the Fe2+ -Mg2+-interdiffusion in olivine (II). Ber Bunsenges Phys Chem 88:140–145
O'Neill HStC (1987) Quartz-fayalite-iron and quartz-fayalite-magnetite equilibria and the free energy of formation of fayalite (Fe2SiO4) and magnetite (Fe3O4). Am Mineral 72:67–75
O'Neill HStC (1988) Systems Fe-O and Cu-O: Thermodynamic data for the equilibria Fe-“FeO,”, Fe-Fe3O4, “FeO” -Fe3O4, Cu-Cu2O, and Cu2O-CuO from emf measurements. Am Mineral 73:470–486
Reddy KPR, Oh SM, Major Jr LD, Cooper AR (1980) Oxygen diffusion in forsterite. J Geophys Res 85:322–26
Ricoult DL, Kohlstedt DL (1983) Structural width of low-angle grain boundaries in olivine. Phys Chem Minerals 9:133–138
Robie RA, Hemingway BS, Fisher JR (1978) Thermodynamic properties of minerals and related substances at 298.15 K and 1 bar (105 Pascals) pressure and at higher temperatures. United States Printing Office, Geological Survey Bulletin 1452, Washington
Ryerson FJ, Durham WB, Cherniak DJ, Lanford WA (1989) Oxygen diffusion in olivine: Effect of oxygen fugacity and implications for creep. J Geophys Res 94:4105–4118
Schmalzried H (1978) Reactivity and point defects of double oxides with emphasis on simple silicates. Phys Chem Minerals 2:279–294
Schwab RG, Küstner D (1981) Die Gleichgewichtsfugazitäten technologisch und petrologisch wichtiger Sauerstoffpuffer. Neues Jahrb Mineral Abh 140:111–142
Sockel HG (1974) Defect structure and electrical conductivity of crystalline ferrous silicate. In: Defects and Transport in Oxides, Smeltzer MS, Jaffee RJ (eds). Plenum Press, New York, pp 341–354
Watson EB (1986) An experimental study of oxygen transport in dry rocks and related kinetic phenomena. J Geophys Res 91:14>117–14>131
Watson EB (1991) Diffusion in fluid-bearing and slightly-melted rocks: Experimental and numerical approaches illustrated by iron transport in dunite. Contrib Mineral Petrol 107:417–434
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Fisler, D.K., Mackwell, S.J. Kinetics of diffusion-controlled growth of fayalite. Phys Chem Minerals 21, 156–165 (1994). https://doi.org/10.1007/BF00203146
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DOI: https://doi.org/10.1007/BF00203146