Incorporation of small molecules in silicate melts may provide an important mecha-nism for storing noble gases in the deep Earth, yet the means by which chemicallyinert noble gases enter and are retained in silica-based materials is not understood.High pressure, room temperature sound velocity measurements on silica and natu-ral basalt glasses in different pressure-transmitting media reveal that neon entersthe structure of silicate glasses and enhances their elastic strengths, whereas anethanol-methanol mixture does not. Combined with literature data, we foundthe incorporation of small molecules intosilica and basalt glasses is controlledby the void size distribution of the glass and size of the molecules. Pressureprimarily reduces the size of noble gases, thereby increasing their solubilities insilicate melts and glasses.

Yang, H., Gleason, A.E., Tkachev, S.N., Chen, B., Jeanloz, R., Mao, W.L. (2021) Noble gas incorporation into silicate glasses: implications for planetary volatile storage. Geochem. Persp. Let. 17, 1–5. DOI: 10.7185/geochemlet.2105 abstract (PDF)

 

Sound velocities of vitreous silica under high pressure in different pressure media. M-E represents 41 Methanol-Ethanol mixture.Errors of the velocities are estimated from statistical uncertainties arising from the peak fitting. Typical errors are less than 1.5 % and smallerthan the size of the symbols. For both theVPandVSof silica in different noble gas media, we found a consistent trend for the acousticvelocitiesHe>Ne>ArM-E. The abnormal velocity minimum at around 25 GPa can be attributed to the rearrangement of SiO4tetra-hedra in the vitreous silica structure