Structure of shock compressed model basaltic glass: Insights from O K-edge X-ray Raman scattering and high-resolution27Al NMR spectroscopy

• Published in: Geophysical research letters 2012-03, Vol.39 (5), p.n/a
• Main Authors: Lee, Sung Keun, Park, Sun Young, Kim, Hyo-Im, Tschauner, Oliver, Asimow, Paul, Bai, Ligang, Xiao, Yuming, Chow, Paul
• Format: Article
• Language: English
• Subjects: basaltic glass; inelastic X-ray scattering; NMR; shock compressed glass
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2012GL050861

The detailed atomic structures of shock compressed basaltic glasses are not well understood. Here, we explore the structures of shock compressed silicate glass with a diopside–anorthite eutectic composition (Di64An36), a common Fe‐free model basaltic composition, using oxygen K‐edge X‐ray Raman scattering and high‐ resolution27Al solid‐state NMR spectroscopy and report previously unknown details of shock‐induced changes in the atomic configurations. A topologically driven densification of the Di64An36glass is indicated by the increase in oxygen K‐edge energy for the glass upon shock compression. The first experimental evidence of the increase in the fraction of highly coordinated Al in shock compressed glass is found in the27Al NMR spectra. This unambiguous evidence of shock‐induced changes in Al coordination environments provides atomistic insights into shock compression in basaltic glasses and allows us to microscopically constrain the magnitude of impact events or relevant processes involving natural basalts on Earth and planetary surfaces. Key Points Shock‐induced increase in Al coordination number in basaltic glass is revealed The Al site fraction in glass can be used a new shock index for impact events Impact event on basalts in planetary surfaces results in highly coordinated Al