Identification and characterization of high-pressure silica polymorphs using nondestructive microanalyses

Abstract

High-pressure silica polymorphs provide constraint on shock condition of asteroid collision. In this study, Raman and cathodoluminescence (CL) spectroscopy has been performed to identify the polymorphs as nondestructive microanalyses. Raman spectra of seifertite consist of peaks corresponding to the calculated Raman shift. Seifertite has the peaks after the prolonged laser beam and survive post-shock thermal history with relatively high temperature. Deconvoluted CL spectra of the seifertite show distinct emission components at 3.79 and 3.25 eV from those of other silica polymorphs. CL and Raman spectroscopy enables identification of silica polymorphs and provides valuable information on impact history.