Compressional wave velocities in possible mantle rocks to pressures of 30 kilobars

The velocities of compressional waves are reported to hydrostatic pressures of 30 kbar for pyroxenites, eclogites, and a dunite. The data above 10 kbar, when corrected for length changes, permit the determination of pressure coefficients of compressional wave velocities, which range from 0.010 km s−1 kbar−1 in eclogite to 0.014 km s−1 kbar−1 in pyroxenite. It is shown that pressure coefficients of velocity for rocks determined below 10 kbar are generally unreliable due to the influence of porosity. The pressure coefficient of velocity measured for the dunite agrees well with similar data from single-crystal olivine; however, pressure coefficients of velocity for the pyroxenites are significantly lower than measurements for single-crystal bronzite.