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On the Timescale of Magma Ocean Solidification and Its Chemical Consequences: 1. Thermodynamic Database for Liquid at High Pressures
Author(s) -
Miyazaki Yoshinori,
Korenaga Jun
Publication year - 2019
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1029/2018jb016932
Subject(s) - thermodynamics , ternary operation , mantle (geology) , mixing (physics) , thermal , materials science , geology , physics , geophysics , computer science , quantum mechanics , programming language
We present a new method to construct an internally consistent thermodynamic model using a compilation of high‐pressure melting experiments. The steepest descent method and Monte Carlo sampling are combined to constrain all model parameters simultaneously instead of determining each parameter sequentially from relevant experiments. Our approach is applied to the published melting experiments on mantle materials to obtain the thermodynamic parameters of the MgO‐FeO‐SiO 2 ternary system. Inversion with the subsets of experimental data is conducted as well to investigate the source of discrepancy among existing studies, and the key parameters are found to be the thermal expansivity of SiO 2 and the excess volume of mixing between MgO and SiO 2 . Mixing between FeO and SiO 2 is only constrained with large uncertainty, which could also imply that oxides with low concentrations have minimal effects on melting. Constraining the thermodynamics of MgO and SiO 2 will be important for a better understanding of mantle melting at high pressures.