Study of the Earth’s Interior using Measurements of Sound Velocities in Minerals by Ultrasonic Interferometry Robert C. Liebermann*1,2,, Xuebing Wang1, Ting Chen1, Yongtao Zou2, Baosheng Li1,2 1Department of Geosciences, Stony Brook University, Stony Brook, NY USA 2Mineral Physics Institute, Stony Brook University, Stony Brook, NY USA

English Abstract:

This paper reviews the progress of the technology of ultrasonic interferometry from the early 1950s to the present day. During this period of more than 60 years, sound wave velocity measurements have been increased from pressures less than 1 GPa and temperatures less than 800K to conditions above 25 GPa and temperatures of 1800K. This technique is complimentary to other direct methods to measure sound velocities (such as Brillouin and impulsive stimulated scattering) as well as indirect methods (e.g., resonance ultrasound spectroscopy, static or shock compression, inelastic X-ray scattering). Newly developed pressure calibration methods and data analysis procedures using a finite strain approach are described and applied to major mantle minerals for the implication for the composition of the Earth’s mantle. The state-of-the-art ultrasonic experiments performed in conjunction with synchrotron X-radiation can achieve simultaneous measurements of the elastic bulk and shear moduli and their pressure and temperature derivatives with direct determination of pressure. Recent examples of such studies are presented for a synthetic KLB-1 peridotite and polycrystalline SiO₂-coesite and the current status and outlook/challenges for future experiments are summarized.

This research is supported by the U. S. National Science Foundation and Department of Energy.