HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation
Journal articles

Melting behavior of SiO2 up to 120 GPa

Abstract : The structure of liquid silicates is commonly described as a statistical mixture of various atomic entities with relative abundances that can vary with pressure, temperature and composition. Unfortunately, this view remains largely theoretical due to scarce experimental reports on the silicate melt structure, in particular under pressure. We performed X-ray diffraction of the SiO2 end-member to probe the melting curve up to ~120 GPa and 7000 K, and the melt structure up to ~80 GPa. We confirm the steep increase of the melting curve above ~14 GPa when stishovite becomes stable over coesite in subsolidus conditions, with a slope of about 80 K/GPa. Then, around 45 GPa and 5400 K, the melting curve flattens significantly, an effect most likely reflecting the densification of the SiO2 melt structure. The signal of diffuse X-ray scattering is compatible with a change of the Si coordination number from 4 to 6 along the melting curve, in agreement with previous works reporting a similar evolution during the cold compression of SiO2-glass. Because of the limited pressure range (within 10 to 20 GPa) in which the melting curve changes its slope, we speculate a difficult coexistence of tetrahedral SiO4 and octahedral SiO6 units in SiO2 melt at high pressures.
Document type :
Journal articles
Complete list of metadata

Contributor : Sylvaine Jouhannel Connect in order to contact the contributor
Submitted on : Friday, January 31, 2020 - 10:18:17 AM
Last modification on : Friday, December 3, 2021 - 11:43:11 AM
Long-term archiving on: : Friday, May 1, 2020 - 1:57:40 PM


Files produced by the author(s)


Distributed under a Creative Commons Attribution - NonCommercial 4.0 International License



Denis Andrault, G. Morard, G. Garbarino, M. Mezouar, Mohamed Ali Bouhifd, et al.. Melting behavior of SiO2 up to 120 GPa. Physics and Chemistry of Minerals, Springer Verlag, 2020, 47 (2), ⟨10.1007/s00269-019-01077-3⟩. ⟨hal-02462133⟩



Record views


Files downloads