General relationships among sound speeds: I. New experimental information

Abstract

New ultrasonic data on some crystal structures important in mantle mineralogy are presented for compounds of Mg 2GeO 4, Fe 2GeO 4 and Fe 2SiO 4, both in olivine and spinel structures, and of GeO 2, SnO 2 and SiO 2 in the rutile structure, as their elastic parameters were determined by a powder—matrix method. With these new elasticity data, a power law for the velocity-density relationship arising from lattice dynamics is examined. Specific conclusions made are: (1) ultrasonic measurements on germanate compounds become very useful for estimating the elastic parameters of their silicate analogs: (2) the power law describes the velocity-density relationship for high-pressure polymorphs better than Birch's linear law: and (3) the power law is useful in our study of the elasticity and constitution of the elasticity and constitution of the deep interiors of the earth and other planets.