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First-Principles Computation Of Diffusional Mg Isotope Fractionation In Silicate Melts, Haiyang Luo, Bijaya B. Karki, Dipta B. Ghosh, Huiming Bao
First-Principles Computation Of Diffusional Mg Isotope Fractionation In Silicate Melts, Haiyang Luo, Bijaya B. Karki, Dipta B. Ghosh, Huiming Bao
Faculty Publications
© 2020 Elsevier Ltd Diffusional isotope fractionation occurs in geochemical processes (such as magma mixing, bubble growth, and crystal growth), even at magmatic temperatures. Isotopic mass dependence of diffusion is commonly expressed as [Formula presented], where Di and Dj are diffusion coefficients of two isotopes whose masses are mi and mj. How the dimensionless empirical parameter β depends on temperature, pressure, and composition remains poorly constrained. Here, we conducted a series of first-principles molecular dynamics simulations to evaluate the β factor of Mg isotopes in MgSiO3 and Mg2SiO4 melts using pseudo-isotope method. In particular, we considered interactions between Mg isotopes …
First-Principles Computation Of Diffusional Mg Isotope Fractionation In Silicate Melts, Haiyang Luo, Bijaya B. Karki, Dipta B. Ghosh, Huiming Bao
First-Principles Computation Of Diffusional Mg Isotope Fractionation In Silicate Melts, Haiyang Luo, Bijaya B. Karki, Dipta B. Ghosh, Huiming Bao
Faculty Publications
© 2020 Elsevier Ltd Diffusional isotope fractionation occurs in geochemical processes (such as magma mixing, bubble growth, and crystal growth), even at magmatic temperatures. Isotopic mass dependence of diffusion is commonly expressed as [Formula presented], where Di and Dj are diffusion coefficients of two isotopes whose masses are mi and mj. How the dimensionless empirical parameter β depends on temperature, pressure, and composition remains poorly constrained. Here, we conducted a series of first-principles molecular dynamics simulations to evaluate the β factor of Mg isotopes in MgSiO3 and Mg2SiO4 melts using pseudo-isotope method. In particular, we considered interactions between Mg isotopes …
Mixed Incorporation Of Carbon And Hydrogen In Silicate Melts Under Varying Pressure And Redox Conditions, Bijaya B. Karki, Dipta B. Ghosh, Dipendra Banjara
Mixed Incorporation Of Carbon And Hydrogen In Silicate Melts Under Varying Pressure And Redox Conditions, Bijaya B. Karki, Dipta B. Ghosh, Dipendra Banjara
Faculty Publications
Volatiles including carbon and hydrogen are generally considered to be more soluble in silicate melts than in mantle rocks. How these melts contribute to the storage and distribution of key volatiles in Earth's interior today and during its early evolution, however, remains largely unknown. It is essential to improve our knowledge about volatiles-bearing silicate magmas over the entire mantle pressure regime. Here we investigate molten Mg Fe SiO (x=0, 0.25) containing both carbon and hydrogen using first-principles molecular dynamics simulations. Our results show that the dissolution mechanism of the binary volatiles in melts varies considerably under different conditions of pressure …
Effects Of Valence And Spin Of Fe In Mgsio3 Melts: Structural Insights From First-Principles Molecular Dynamics Simulations, Dipta B. Ghosh, Bijaya B. Karki
Effects Of Valence And Spin Of Fe In Mgsio3 Melts: Structural Insights From First-Principles Molecular Dynamics Simulations, Dipta B. Ghosh, Bijaya B. Karki
Faculty Publications
Iron (Fe) is present in terrestrial melts and at all depths inside the Earth. How Fe in its varying oxidation and spin states influences the properties of silicate melts is of critical importance to the understanding of the chemical evolution of our planet. Here, we report the results of first-principles molecular dynamics simulations of molten Fe-bearing MgSiO over a wide pressure range covering the entire mantle. Our results suggest that the structural properties of the host melt, such as the average bond length and coordination in Mg–O and Si–O do not differ much when compared with the pure melt. More …