Iron and silicon isotope fractionation in silicate melts using first-principles molecular dynamics

Rabin, S.; Blanchard, Marc; Pinilla, Carlos; Poitrasson, Franck; Grégoire, Marilaure

doi:10.1016/j.gca.2022.11.017

Cited by 5 publications

(2 citation statements)

References 117 publications

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“…where K is the atomic kinetic energy, can be obtained by determining the partial vibrational density of states (VDOS) based on the velocity autocorrelation function 72,73 . This method incorporates anharmonic effects on the structures, but its effectiveness relies on the length of the trajectory used to obtain meaningful results given that the noise in the velocity auto-correlation function increases with the length of the time interval and could lead to nonconverged spectra 73 .…”

Section: Equilibrium Isotope Fractionationmentioning

confidence: 99%

“…This method incorporates anharmonic effects on the structures, but its effectiveness relies on the length of the trajectory used to obtain meaningful results given that the noise in the velocity auto-correlation function increases with the length of the time interval and could lead to nonconverged spectra 73 . Moreover, the VDOS displays a non-zero value at zero frequency due to diffusion effects, which should be removed before calculating β, posing a challenge 72 . Furthermore, deriving β in this way may introduce systematic errors when compared with β values of minerals obtained from full vibrational frequencies calculated under static conditions 73 .…”

Section: Equilibrium Isotope Fractionationmentioning

confidence: 99%

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Heavy magnesium isotopic signatures in arc lavas may be attributed to dehydration of subducting hydrated mantle

Deng,

Chen,

Wang

et al. 2024

Commun Earth Environ

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Fluids released from subducting slabs profoundly affect mantle composition, rock melting points, and arc magma generation. However, identifying fluid sources (sediments, crust, or mantle) and their ascent paths remains challenging. Magnesium isotopes are potential tracers for subduction-related fluids, though their behavior during hydrous peridotite dehydration remains unclear. Here we determined the equilibrium magnesium isotope fractionation factors between aqueous fluids and hydrous peridotitic minerals using first-principles calculations. Aqueous fluids prefer heavy magnesium isotopes relative to mantle silicate minerals, indicating that fluids released during hydrous peridotite dehydration are enriched in heavy magnesium isotopes relative to the residual minerals. Our simulations proposed that magnesium isotope variations in arc lavas from different subduction zones could be attributed to different dehydration reactions influenced by subduction zone thermal structures. This study highlights the potential of magnesium isotopes for tracing fluids originating from subducting hydrated mantle, providing insights into the thermal structure of various subduction zones.

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Section: Equilibrium Isotope Fractionationmentioning

confidence: 99%