Elastic wave velocities of peridotite KLB-1 at mantle pressures and implications for mantle velocity modeling

Abstract

Compressional (VP) and shear (VS) wave velocities of a synthetic KLB-1 peridotite were measured for the first time up to 10GPa using ultrasonic interferometry. Analysis of the P and S wave velocities yielded K0=123(1)GPa, K0′=5.1(2), G0=75(1)GPa, and G0′=1.3(1) for the bulk and shear moduli and their pressure derivatives. Comparison with Voigt-Reuss-Hill (VRH) calculations based on literature elasticity data for its constituent minerals indicates that the experimentally measured P and S wave velocities, densities, bulk sound velocities, and VP/VS ratios fall close to the lower limit of VRH averages associated with the uncertainties of the mineral elasticity data. A comparison with previous modeling of mantle compositions implies that the velocities for an aggregate with the pyrolitic composition of KLB-1 are in close agreement with seismic data at the depths of the Earth's upper mantle. Key Points Hot pressing of high-quality synthetic mantle rocks with pyrolitic composition First results on P and S wave velocities on KLB-1 peridotite to mantle pressures Direct comparison between measured velocities and mantle modeling approaches