Discovery of Elgoresyite, (Mg,Fe)5Si2O9: Implications for Novel Iron Magnesium Silicates in Rocky Planetary Interiors
Résumé
As the most abundant material of rocky Planets, alhigh-pressure PolYmorPhs of iron- andinum. bearingmagnesium silicates have long been soughtbybuoth observations and experiments. Meanwhile, it wasrecently revealed that iron oxides form (Fe0.)m (Fe203),, bomologous series above -'10 GPa according to laboratory high-pressureexperiments. Here, we report a new high-pressure iron-magnesium silicate, recently approved by the International Mineralogical Association as a new mineral (No. 2020-086) and named elgoresy,ite,in a shock-induced melt vein ot., the Suizhou L6 chondrite with a chemistry of (mg,Fe) ironi209. The crystal structure of this new silicate is the same as the oxide Fe709, strongly suggesting that silicates also form ((Mg,Fe)) (SiO2), series that are isostructural to iron oxides via0,m +Si(Mg2+,Fe') 2Fe3' substitution. To test this hypothesis, the phase relationships of the silicates and iron oxides should further investigated at higher temperature conditions. Newly found iron -magnesium silicate is a potential constituent mineral rocky planets with relatively high Mg0 + Fe0 content.
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