Fig. 2.

X-ray diffraction patterns of En80 at 108 GPa and San Carlos olivine at 144 GPa. Both were taken at 300 K after laser-heating to 2,000 K. ppv peaks are marked with *. The San Carlos olivine spectra shows that the sample had converted to only ppv + mw phases. Splitting of the Re 100 and 101 peaks may be a result of repeated temperature cycling that transformed the edge of the gasket material into a double hexagonal close-packed (hcp) structure [similar to behavior observed in Fe and Co (21, 22)] or a hcp phase reaction product. The En80 sample shows conversion of the amorphized sample into ppv + pv. The ppv 132 peak is on the short-wavelength shoulder of a pv peak. The wavelength of the monochromatic beam was 0.3344 Å.