CRYSTAL NUCLEATION IN HYDROUS RHYOLITE: EXPERIMENTAL DATA APPLIED TO CLASSICAL THEORY

Show simple item record

dc.contributor.author Hammer J.E.
dc.date.accessioned 2022-04-11T05:21:38Z
dc.date.available 2022-04-11T05:21:38Z
dc.date.issued 2004
dc.identifier https://www.elibrary.ru/item.asp?id=14239572
dc.identifier.citation American Mineralogist, 2004, 89, 11-12, 1673-1679
dc.identifier.issn 0003-004X
dc.identifier.uri https://repository.geologyscience.ru/handle/123456789/37043
dc.description.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.
dc.title CRYSTAL NUCLEATION IN HYDROUS RHYOLITE: EXPERIMENTAL DATA APPLIED TO CLASSICAL THEORY
dc.type Статья


Files in this item

This item appears in the following Collection(s)

  • ELibrary
    Метаданные публикаций с сайта https://www.elibrary.ru

Show simple item record