Argon and CO2 on the race track in silicate melts: A tool for the development of a CO2 speciation and diffusion model

Nowak, Marcus; Schreen, Dominik; Spickenbom, K.

doi:10.1016/j.gca.2004.06.002

Cited by 76 publications

(124 citation statements)

References 43 publications

Supporting

Mentioning

111

Contrasting

Order By: Relevance

“…Theirs and subsequent studies also infer the predominance of molecular CO 2 in rhyolitic and more siliceous compositions with increasing importance of carbonate at decreasing SiO 2 concentration. Unlike the situation with dissolved water in silicate melts, where the mechanism of diffusion is a first-order function of speciation (Wasserburg 1988;Behrens and Nowak 1997; recent literature summary in Zhang and Ni 2010), the diffusivity of carbon dioxide does not exhibit a strong dependence on the relative abundance of molecular CO 2 and carbonate species (Nowak et al 2004). This observation suggests that it may be possible to model carbon dioxide solubility in silicate liquids with a single melt species.…”

Section: Carbon Dioxide Solubility In Silicate Liquidsmentioning

confidence: 99%

An H2O–CO2 mixed fluid saturation model compatible with rhyolite-MELTS

Ghiorso

Gualda

2015

Contrib Mineral Petrol

473

397

View full text Add to dashboard Cite

a maximum in melt CO 2 at nonzero H 2 O melt concentrations, regardless of bulk composition. This feature is universal and can be attributed to the dominance of hydroxyl speciation at low water concentrations. The model is applied to four examples. The first involves estimation of pressures from H 2 O-CO 2 -bearing glass inclusions found in quartz phenocrysts of the Bishop Tuff. The second illustrates H 2 O and CO 2 partitioning between melt and fluid during fluid-saturated equilibrium and fractional crystallization of MORB. The third example demonstrates that the position of the quartz-feldspar cotectic surface is insensitive to melt CO 2 contents, which facilitates geobarometry using phase equilibria. The final example shows the effect of H 2 O and CO 2 on the crystallization paths of a high-silica rhyolite composition representative of the late-erupted Bishop Tuff. Software that implements the model is available at ofm-research.org, and the model is incorporated into the latest version (1.1+) of rhyolite-MELTS.

show abstract

Section: Carbon Dioxide Solubility In Silicate Liquidsmentioning

confidence: 99%

An H2O–CO2 mixed fluid saturation model compatible with rhyolite-MELTS

Ghiorso

Gualda

2015

Contrib Mineral Petrol

473

397

View full text Add to dashboard Cite

show abstract

“…Because the diffusion of CO 2 in silicate melt has been shown to be relatively independent of speciation and anhydrous melt composition (Nowak et al, 2004), CO 2 diffusion is less complicated than H 2 O diffusion. The diffusivity is well characterized for Fuego melts with a pressure-and H 2 O-dependent Arrhenius equation (Fig.…”

Section: Volatile Diffusivitymentioning

confidence: 99%

NanoSIMS results from olivine-hosted melt embayments: Magma ascent rate during explosive basaltic eruptions

Lloyd

Ruprecht

Hauri

et al. 2014

Journal of Volcanology and Geothermal Research

109

110

View full text Add to dashboard Cite

show abstract

“…There is some information on D f / D b , but only for CO 2 and only in a limited number of compositions (Nowak et al, 2004). Assuming D f /D b = 1000 and E f = 0.43 for Ca in albitic liquid, a value of E tot = 0.36 would indicate that K % 27 for the Ca-bearing species.…”

Section: Model For Diffusive Isotope Effects In Silicate Liquidsmentioning

confidence: 99%

Influence of liquid structure on diffusive isotope separation in molten silicates and aqueous solutions

Watkins

DePaolo

Ryerson

et al. 2011

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

Molecular diffusion in natural volcanic liquids discriminates between isotopes of major ions (e.g., Fe, Mg, Ca, and Li). Although isotope separation by diffusion is expected on theoretical grounds, the dependence on mass is highly variable for different elements and in different media. Silicate liquid diffusion experiments using simple liquid compositions were carried out to further probe the compositional dependence of diffusive isotopic discrimination and its relationship to liquid structure. Two diffusion couples consisting of the mineral constituents anorthite (CaAl 2 Si 2 O 8 ; denoted AN), albite (NaAlSi 3 O 8 ; denoted AB), and diopside (CaMgSi 2 O 6 ; denoted DI) were held at 1450°C for 2 h and then quenched to ambient pressure and temperature. Major-element as well as Ca and Mg isotope profiles were measured on the recovered quenched glasses. In both experiments, Ca diffuses rapidly with respect to Si. In the AB-AN experiment, D Ca /D Si ~ 20 and the efficiency of isotope separation for Ca is much greater than in natural liquid experiments where D Ca /D Si ~ 1. In the AB-DI experiment, D Ca /D Si ~ 6 and the efficiency of isotope separation is between that of the natural liquid experiments and the AB-AN experiment. In the AB-DI experiment, D Mg /D Si ~ 1 and the efficiency of isotope separation for Mg is smaller than it is for Ca yet similar to that observed for Mg in natural liquids.The results from the experiments reported here, in combination with results from natural volcanic liquids, show clearly that the efficiency of diffusive separation of Ca isotopes is systematically related to the solvent-normalized diffusivity-the ratio of the diffusivity of the cation (D Ca ) to the diffusivity of silicon (D Si ). The results on Ca isotopes are consistent with available data on Fe, Li, and Mg isotopes in silicate liquids, when considered in terms of the parameter D cation /D Si . Cations diffusing in aqueous solutions display a similar relationship between isotopic separation efficiency and D cation =D H 2 O , although the efficiencies are smaller than in silicate liquids. Our empirical relationship provides a tool for predicting the magnitude of diffusive isotopic effects in many geologic environments and a basis for a more comprehensive theory of isotope separation in liquid solutions. We present a conceptual model for the relationship between diffusivity and liquid structure that is consistent with available data.

show abstract

Argon and CO2 on the race track in silicate melts: A tool for the development of a CO2 speciation and diffusion model

Cited by 76 publications

References 43 publications

An H2O–CO2 mixed fluid saturation model compatible with rhyolite-MELTS

An H2O–CO2 mixed fluid saturation model compatible with rhyolite-MELTS

NanoSIMS results from olivine-hosted melt embayments: Magma ascent rate during explosive basaltic eruptions

Influence of liquid structure on diffusive isotope separation in molten silicates and aqueous solutions

Contact Info

Product

Resources

About