Raman spectra of a single crystal of hydrous Fo89- ringwoodite have been measured in a diamond-anvil cell at room temperature to 60 GPa. Strong peaks corresponding to asymmetric and symmetric stretching vibrations of the SiO4 tetrahedra are observed at 796 and 841 cm-1 respectively. Additional bands occur in the range 709-939 and 100-250 cm-1. The SiO4 stretching modes of the spinel structure shift continuously up to 60 GPa. Near 40 GPa new Raman bands emerge in the region 550-680 cm-1 gaining intensity to the maximum pressure, a change that is reversible on pressure release. This pressure-induced modification in the structure appears to be related to structural complexity generated by both Fe and proton substitution.
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)