Shock-Produced Olivine Glass: First Observation

Science  29 Jul 1977:
Vol. 197, Issue 4302, pp. 457-459
DOI: 10.1126/science.197.4302.457


Transmission electron microscope (TEM) observations of an experimentally shock-deformed single crystal of natural peridot, (Mg0.88Fe0.12)2SiO4, recovered from peak pressures of about 56 x 109 pascals revealed the presence of amorphous zones located within crystalline regions with a high density of tangled dislocations. This is the first reported observation of olivine glass. The shocked sample exhibits a wide variation in the degree of shock deformation on a small scale, and the glass appears to be intimately associated with the highest density of dislocations. This study suggests that olivine glass may be formed as a result of shock at pressures above about 50 to 55 x 109 pascals and that further TEM observations of naturally shocked olivines may demonstrate the presence of glass.