In situ X-ray diffraction of silicate liquids and glasses under dynamic and static compression to megabar pressures

Properties of liquid silicates under high-pressure and high-temperature conditions are critical for modeling the dynamics and solidification mechanisms of the magma ocean in the early Earth, as well as for constraining entrainment of melts in the mantle and in the present-day core–mantle boundary. H...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2020-06, Vol.117 (22), p.11981-11986
Main Authors: Morard, Guillaume, Hernandez, Jean-Alexis, Guarguaglini, Marco, Bolis, Riccardo, Benuzzi-Mounaix, Alessandra, Vinci, Tommaso, Fiquet, Guillaume, Baron, Marzena A., Shim, Sang Heon, Ko, Byeongkwan, Gleason, Arianna E., Mao, Wendy L., Alonso-Mori, Roberto, Lee, Hae Ja, Nagler, Bob, Galtier, Eric, Sokaras, Dimosthenis, Glenzer, Siegfried H., Andrault, Denis, Garbarino, Gaston, Mezouar, Mohamed, Schuster, Anja K., Ravasio, Alessandra
Format: Article
Language:English
Subjects:
amorphous silicates
Boundary conditions
Compression
Condensed Matter
Diamond anvil cells
Diffraction patterns
Earth core
Earth mantle
Earth Sciences
Entrainment
Geophysics
GEOSCIENCES
high pressure
High temperature
Liquids
Magma
Materials Science
Melts
Molecular dynamics
Ocean models
Physical Sciences
Physics
Room temperature
Sciences of the Universe
shock compression
Silica
Silicates
Silicon
Solidification
static compression
Temperature
X-ray diffraction
XFEL diffraction
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Summary:Properties of liquid silicates under high-pressure and high-temperature conditions are critical for modeling the dynamics and solidification mechanisms of the magma ocean in the early Earth, as well as for constraining entrainment of melts in the mantle and in the present-day core–mantle boundary. Here we present in situ structural measurements by X-ray diffraction of selected amorphous silicates compressed statically in diamond anvil cells (up to 157 GPa at room temperature) or dynamically by laser-generated shock compression (up to 130 GPa and 6,000 K along the MgSiO3 glass Hugoniot). The X-ray diffraction patterns of silicate glasses and liquids reveal similar characteristics over a wide pressure and temperature range. Beyond the increase in Si coordination observed at 20 GPa, we find no evidence for major structural changes occurring in the silicate melts studied up to pressures and temperatures exceeding Earth’s core mantle boundary conditions. This result is supported by molecular dynamics calculations. Our findings reinforce the widely used assumption that the silicate glasses studies are appropriate structural analogs for understanding the atomic arrangement of silicate liquids at these high pressures.
ISSN:0027-8424
1091-6490
1091-6490
DOI:10.1073/pnas.1920470117