Infrared spectroscopy of hydrous silicate melts to 1000 degrees C and 10 kbar; direct observation of H<sub>2</sub>O speciation in a diamond-anvil cell

Shen, Andy H.; Keppler, Hans

doi:10.2138/am-1995-11-1223

Cited by 166 publications

(83 citation statements)

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“…It should be noted that the measurements of the water speciation on glasses quenched from high temperature experiments do not represent isothermal values (e.g. Romano et al, 1995;Shen and Keppler, 1995;Behrens and Nowak, 2003), as the water species keep reacting during quenching and the reaction is actually frozen only at the glass transition temperature, which differs as a function of water content itself. However, as the calorimetric measurements are performed in the proximity of the glass transition temperature, and assuming that temperature does not significantly affect the anhydrous liquid heat capacities, comparison between the speciation curve and the calorimetric curve, although not isothermal, is still possible.…”

Section: Heat Capacity Of Water In Silicate Liquidsmentioning

confidence: 99%

Heat capacity, configurational heat capacity and fragility of hydrous magmas

Genova

Romano

Giordano

et al. 2014

Geochimica et Cosmochimica Acta

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International audienceThe glassy and liquid heat capacities of four series of dry and hydrous natural glasses and magma as a function of temperature and water content (up to 19.9 mol%) were investigated using differential scanning calorimetry (DSC). The analyzed compositions are basalt, latite, trachyte and pantellerite. The results of this study indicate that the measured heat capacity of glasses (Cpg) is a linear function of composition and is well reproduced by the empirical model of Richet (1987). For the investigated glasses, the partial molar heat capacity of water can be considered as independent of composition, in agreement with Bouhifd et al. (2006). For hydrous liquids, the heat capacity (Cpliq) decreases nonlinearly with increasing water content. Previously published models, combined with the partial molar heat capacity of water from the literature, are not able to reproduce our experimental data in a satisfactory way. We estimated the partial molar heat capacity of water (CpH2O) in hydrous magma over a broad compositional range. The proposed value is 41 ± 3 J mol-1 K-1. Water strongly affects the configurational heat capacity at the glass transition temperature [Cpconf (Tg)]. An increases of Cpconf (Tg) with water content was measured for the polymerized liquids (trachyte and pantellerite), while the opposite behavior was observed for the most depolymerized liquids (basalt and latite). Structural and rheological implications of this behavior are discussed in light of the presented results

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Section: Heat Capacity Of Water In Silicate Liquidsmentioning

confidence: 99%

Heat capacity, configurational heat capacity and fragility of hydrous magmas

Genova

Romano

Giordano

et al. 2014

Geochimica et Cosmochimica Acta

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“…Silver and Stolper 1989) or direct in situ spectroscopic measurements (e.g. Nowak and Behrens 1995;Shen and Keppler 1995). This kinetic phenomenon is now well established and used in particular as a geospeedometer (e.g.…”

Section: Water Speciation In Basaltic Liquids/meltsmentioning

confidence: 99%

The H2O solubility of alkali basaltic melts: an experimental study

Lesne

Scaillet

Pichavant

et al. 2010

Contrib Mineral Petrol

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The H2O solubility of alkali basaltic melts: an experimental study. Contributions to Mineralogy and Petrology, Springer Verlag, 2011, 162 (1) Our results show that at pressures above 1 kbar, alkali basalts dissolve more water than typical mid-ocean ridge basalts (MORB). Combination of our data with those from previous studies allows the following simple empirical model for the water solubility of basalts of varying alkalinity and fO 2 to be derived:where H 2 O MORB is the water solubility at the calculated P, using the model of Dixon et al. (1995). This equation reproduces the existing database on water solubilities in basaltic melts to within 5%. Interpretation of the speciation data in the context of the glass transition theory shows that water speciation in basalt melts is severely modified during quench. At magmatic temperatures, more than 90% of dissolved water forms hydroxyl groups at all water contents, whilst in natural or synthetic glasses, the amount of molecular water is much larger. A regular solution model with an explicit temperature dependence reproduces well-observed water species. Derivation of the partial molar volume of molecular water using standard thermodynamic considerations yields values close to previous findings if room temperature water species are used. When high temperature species proportions are used, a negative partial molar volume is obtained for molecular water. Calculation of the partial molar volume of total water using H 2 O solubility data on basaltic melts at pressures above 1 kbar yields a value of 19 cm 3 /mol in reasonable agreement with estimates obtained from density measurements.

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“…16), 17) It appears that the amount of hydroxyl decreases with the progress of crystallization. The IR spectral change may be due to the structural change of water from hydroxyl to like a molecular water at the expense of the hydroxyl group.…”

Section: Behavior Of Water During Crystallizationmentioning

confidence: 99%

Structural evolution of Er3+ ions in Li2O-Al2O3-SiO2 glass-ceramics

Fujita

Tanabe

2008

J. Ceram. Soc. Japan

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Luminescence characteristics of Er3+ -doped Li2O-Al2O3-SiO2 (LAS) glass and glass-ceramic were evaluated by measuring their absorption spectra, fluorescence spectra and fluorescence lifetime. The absorption cross section of 4 I13/2 -4 I15/2 transition at 1.5 μm increased after cerammization. In contrast, fluorescence intensity of the 1.5 μm emission, fluorescence lifetime, τ f and the Quantum efficiency, η calculated from τ f and spontaneous emission probabilities decreased after cerammization. The decrease of τ f and η was attributed to the increase of the nonradiative decay rate, Wnr caused by accumulation of Er 3+ ions in the glass matrix containing OH ions by cerammization.

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Infrared spectroscopy of hydrous silicate melts to 1000 degrees C and 10 kbar; direct observation of H₂O speciation in a diamond-anvil cell

Cited by 166 publications

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Heat capacity, configurational heat capacity and fragility of hydrous magmas

Heat capacity, configurational heat capacity and fragility of hydrous magmas

The H2O solubility of alkali basaltic melts: an experimental study

Structural evolution of Er3+ ions in Li2O-Al2O3-SiO2 glass-ceramics

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Infrared spectroscopy of hydrous silicate melts to 1000 degrees C and 10 kbar; direct observation of H2O speciation in a diamond-anvil cell

Cited by 166 publications

References 0 publications

Heat capacity, configurational heat capacity and fragility of hydrous magmas

Heat capacity, configurational heat capacity and fragility of hydrous magmas

The H2O solubility of alkali basaltic melts: an experimental study

Structural evolution of Er3+ ions in Li2O-Al2O3-SiO2 glass-ceramics

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Infrared spectroscopy of hydrous silicate melts to 1000 degrees C and 10 kbar; direct observation of H₂O speciation in a diamond-anvil cell