Abstract
Feldspar nucleation rate data obtained by laboratory decompression of hydrous silicate melt are interpreted in view of the classical theory of nucleation (CNT) and a non-classical variation, the diffuse- interface theory (DIT). The nucleation rate data can be modeled by the CNT formalism only if the interfacial free energy (σ) is allowed to vary as a function of composition. The values thus obtained vary by a factor of four (0.024-0.100 J/m2) and decrease systematically over a sixfold increase in dissolved H2O content (0.8-4.8 wt%). This result is qualitatively consistent with the effects of dissolved H2O on the liquid-vapor interfacial free energy in haplogranite magma (Mangan and Sisson 2000) and the liquid-crystal interfacial free energy in the one-component Li-disilicate system (Davis et al. 1997).
The DIT states that the interfacial region between the bulk solid and bulk melt has thermodynamic properties intermediate between these phases, and that σ is defined as the difference between the interfacial enthalpy (Hint) and interfacial entropy (TSint). If the DIT model is correct, the nucleation rate data for feldspar may indicate that: (1) dissolved H2O content controls the spatial distribution of enthalpy and configurational entropy around incipient crystals, and (2) the spatial gradients of these potentials diverge during devolatilization.
This study suggests that crystal nucleation studies may yield insights into the structure and thermodynamics of hydrous melts; likewise, experimental studies are important for refining a physical understanding of nucleation phenomena. Our results can be applied to quantitative numerical models of ascent-driven magma crystallization.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- First-principle study of polytype structures of 1:1 dioctahedral phyllosilicates
- Calorimetry of liquids in the system Na2O-Fe2O3-SiO2
- A Mössbauer study of the oxidation state of Fe in silicate melts
- Nanometer-scale measurements of Fe3+/ΣFe by electron energy-loss spectroscopy: A cautionary note
- The most reduced rock from the moon, Apollo 14 basalt 14053: Its unique features and their origin
- Quantitative analysis of ammonium in biotite using infrared spectroscopy
- Lizardite-chlorite structural relationships and an inferred high-pressure lizardite polytype
- V oxidation state and coordination number in silicate glasses by XAS
- Structure of the fluorapatite (100)-water interface by high-resolution X-ray reflectivity
- Origin of diffuse superstructure reflections in labuntsovite-group minerals
- Isosymmetric structural phase transition of orthoenstatite: Molecular dynamics simulation
- Crystal nucleation in hydrous rhyolite: Experimental data applied to classical theory
- Investigation of polytypes in lepidolite using electron back-scattered diffraction
- Iron partitioning between basaltic melts and clinopyroxene as a function of oxygen fugacity
- The synthesis of zeolite-P, Linde Type A, and hydroxysodalite zeolites from paper sludge ash at low temperature (80 °C): Optimal ash-leaching condition for zeolite synthesis
- High-pressure viscometry of polymerized silicate melts and limitations of the Eyring equation
- Biological control on calcite crystallization: AFM investigation of coccolith polysaccharide function
- Order parameter variation through the C2/m-P21/m phase transition in cummingtonite
- Arsenate sorption on schwertmannite
- Evidence on the structure of synthetic schwertmannite
- Crystal-chemical characterization of tourmalines from the English Lake District: Electron-microprobe analyses and Mössbauer spectroscopy
- Crystal chemistry and paragenesis of compositionally unique (Al-, Fe-, Nb-, and Zr-rich) titanite from Afrikanda, Russia
- Site distribution of Fe2+and Fe3+in the axinite mineral group: New crystal-chemical formula
- Epidote-rich talc-kyanite-phengite eclogites, Sulu terrane, eastern China: P-T-fO₂estimates and the significance of the epidote-talc assemblage in eclogite
- Quantitative mineralogy of the Yukon River system: Changes with reach and season, and determining sediment provenance
- Exsolution of thortveitite, yttrialite, and xenotime during low-temperature recrystallization of zircon from New Caledonia, and their significance for trace element incorporation in zircon
- Mineralogical characterization and genesis of hydrothermal Mn oxides from the flank of the Juan the Fuca Ridge
- Synchrotron X-ray diffraction study of the structure of shafranovskite, K2Na3(Mn,Fe,Na)4[Si9(O,OH)27](OH)2⋅nH2O, a rare manganese phyllosilicate from the Kola peninsula, Russia
- Letter. Coupled cation and oxygen-isotope exchange between alkali feldspar and aqueous chloride solution
Articles in the same Issue
- First-principle study of polytype structures of 1:1 dioctahedral phyllosilicates
- Calorimetry of liquids in the system Na2O-Fe2O3-SiO2
- A Mössbauer study of the oxidation state of Fe in silicate melts
- Nanometer-scale measurements of Fe3+/ΣFe by electron energy-loss spectroscopy: A cautionary note
- The most reduced rock from the moon, Apollo 14 basalt 14053: Its unique features and their origin
- Quantitative analysis of ammonium in biotite using infrared spectroscopy
- Lizardite-chlorite structural relationships and an inferred high-pressure lizardite polytype
- V oxidation state and coordination number in silicate glasses by XAS
- Structure of the fluorapatite (100)-water interface by high-resolution X-ray reflectivity
- Origin of diffuse superstructure reflections in labuntsovite-group minerals
- Isosymmetric structural phase transition of orthoenstatite: Molecular dynamics simulation
- Crystal nucleation in hydrous rhyolite: Experimental data applied to classical theory
- Investigation of polytypes in lepidolite using electron back-scattered diffraction
- Iron partitioning between basaltic melts and clinopyroxene as a function of oxygen fugacity
- The synthesis of zeolite-P, Linde Type A, and hydroxysodalite zeolites from paper sludge ash at low temperature (80 °C): Optimal ash-leaching condition for zeolite synthesis
- High-pressure viscometry of polymerized silicate melts and limitations of the Eyring equation
- Biological control on calcite crystallization: AFM investigation of coccolith polysaccharide function
- Order parameter variation through the C2/m-P21/m phase transition in cummingtonite
- Arsenate sorption on schwertmannite
- Evidence on the structure of synthetic schwertmannite
- Crystal-chemical characterization of tourmalines from the English Lake District: Electron-microprobe analyses and Mössbauer spectroscopy
- Crystal chemistry and paragenesis of compositionally unique (Al-, Fe-, Nb-, and Zr-rich) titanite from Afrikanda, Russia
- Site distribution of Fe2+and Fe3+in the axinite mineral group: New crystal-chemical formula
- Epidote-rich talc-kyanite-phengite eclogites, Sulu terrane, eastern China: P-T-fO₂estimates and the significance of the epidote-talc assemblage in eclogite
- Quantitative mineralogy of the Yukon River system: Changes with reach and season, and determining sediment provenance
- Exsolution of thortveitite, yttrialite, and xenotime during low-temperature recrystallization of zircon from New Caledonia, and their significance for trace element incorporation in zircon
- Mineralogical characterization and genesis of hydrothermal Mn oxides from the flank of the Juan the Fuca Ridge
- Synchrotron X-ray diffraction study of the structure of shafranovskite, K2Na3(Mn,Fe,Na)4[Si9(O,OH)27](OH)2⋅nH2O, a rare manganese phyllosilicate from the Kola peninsula, Russia
- Letter. Coupled cation and oxygen-isotope exchange between alkali feldspar and aqueous chloride solution