SHOCK-INDUCED PLANAR DEFORMATION STRUCTURES IN EXPERIMENTALLY SHOCK-LOADED OLIVINES AND IN OLIVINES FROM CHONDRITIC METEORITES

Shock wave compression experiments in the peak pressure range {reversed tilde equals}50 to 430 kb were performed on single olivine crystals and on specimens drilled from an olivine nodule. All shocked specimens display planar deformation structures parallel to {100}, {010}, {001}, {130}, and {hkl} (bipyramids). The planar structures parallel to {130} and {hkl} are apparently characteristic of shock deformation and may therefore be used as a shock indicator. The crystallographic orientation of the bipyramids depends on the propagation direction of the shock wave in the crystal. The planar structures probably form behind the elastic shock and do not require the final shock state of the olivine to be along the plastic Hugoniot curve. Planar structures parallel to {130} and {hkl} observed in olivines from 10 chondritic meteorites (9 of the L6-group and 1 of the H5-group) indicate that these meteorites have been subjected to shock waves during their history. © 1969.