NMR spectroscopy of experimentally shocked silicate minerals
Abstract
Magic-angle spinning nuclear magnetic resonance (MAS NMR) techniques were used to analyze experimentally shocked quartz and feldspar powders. Si-29 NMR spectra were determined for quartz and labradorite feldspar and Al-27 and Na-23 spectra for labradorite. Both minerals were shocked to 7.5, 16.4, and 22 GPA using the Sandia Momma Bear recovery fixtures. The MAS NMR results for quartz are in full agreement with previous measurements, indicating a high degree of reproducibility. Numerical decomposition of quartz data are consistent with two distinct phases: a defective crystalline quartz and an amorphous-like silica phase. There is a strong correlation between the fraction of amorphous phase and the mean peak shock pressure. The labradorite data are much more complicated, consisting of multiple peaks with no obvious correlation with shock pressure. No amorphous phase was evident from the NMR spectra of the shocked labradorite, nor were high pressure phases detectable for either mineral.
- Publication:
-
Presented at the 1991 American Physical Society (APS) Conference on Compression of Condensed Matter
- Pub Date:
- 1991
- Bibcode:
- 1991aps..conf...18C
- Keywords:
-
- Crystal Defects;
- Crystallinity;
- Feldspars;
- Minerals;
- Nuclear Magnetic Resonance;
- Quartz;
- Shock Tests;
- Silicates;
- Spectroscopic Analysis;
- Aluminum Isotopes;
- Amorphous Materials;
- High Pressure;
- Impact Loads;
- Order-Disorder Transformations;
- Powder (Particles);
- Silicon Dioxide;
- Silicon Isotopes;
- Sodium Isotopes;
- Atomic and Molecular Physics