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High‐resolution solid‐state silicon‐29 nuclear magnetic resonance spectroscopy using “magic‐angle” sample‐spinning can readily detect the presence of the high pressure silica polymorphs coesite and stishovite in whole‐rock samples from a Meteor Crater, Arizona, impact sample, and yields accurate coesite/stishovite ratios. Such determinations are being carried out by partially suppressing (saturating) intense quartz signals (which have long spin‐lattice relaxation times) by means of short experimental recycle‐times. This method enhances the signal‐to‐noise ratios of coesite and stishovite (which have relatively short spin‐lattice relaxation times). For the sample examined, the coesite/stishovite ratio is about 27.
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Yang et al. (1986) studied this question.
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