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A multispecies model for silicate melts II: Constraining macroscopic properties of melts through structural information

English title A multispecies model for silicate melts II: Constraining macroscopic properties of melts through structural information
Applicant Halter Werner
Number 114763
Funding scheme SNSF Professorships
Research institution Institut für Geochemie und Petrologie ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Geochemistry
Start/End 01.03.2007 - 31.03.2008
Approved amount 318'500.00
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Keywords (12)

Silikatschmelzen; Speziation; Thermodynamik; Modellierung; magmatische Prozesse; Vulkanismus; Silicate melt; structure; thermodynamic; speciation; XPS; magma

Lay Summary (English)

Lead
Lay summary
The objective of this study is to develop a thermodynamic model to predict mineral-melt equilibria in natural systems. In the first part of this project we constructed a speciation model for simple binary systems to include a structural basis in the quantification of thermodynamic properties. This model includes some empirical parameters (e.g. activitycoefficients) and hypotheses based on theoretical considerations. To permit a reliable application to multicomponent systems this new project intends to 1. rationalize of empirical parameters or hypotheses and constrain thermodynamic properties through structural data, 2. derive a physically sound thermodynamic model, 3. minimize the number of necessary parameters and so increase the robustness of the model, and 4. quantify thermodynamic properties of species.Hence, the main challenge of this project is to link the atomic-scale structure of silicate liquids to macroscopic thermodynamic and physical properties. Numerous studies of melt structures have been conducted using mainly spectroscopic techniques, but this will be the first attempt to integrate this structural information in a thermodynamic formulation and the quantification of bulk melt properties.We intend to use Nuclear Magnetic Resonance, Raman and X-ray Photoemission Spectroscopy to accurately describe the structure of silicate melts and determine the speciation, bond lengths, coordination number of ions, interaction energies between ions and the various positions of specific ions in the melt structure.
Direct link to Lay Summary Last update: 21.02.2013

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Associated projects

Number Title Start Funding scheme
68687 A multispecies model for silicate melts: the basis for a quantitative understanding of magmativ processes 01.03.2003 SNSF Professorships

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