Elasticity measurements on minerals are the bridge between the observed seismic velocity structure of the Earth and properties at depth, such as chemical composition and temperature. The sound velocity structure of the Earth is known, from the surface to the center of the core, through seismological studies. Moreover, finer details of Earth’s velocity structure will be revealed with improved resolution in the years to come, especially through new instrument deployments. We in the Ultrasonics Laboratory of the Mineral Physics Institute are similarly poised to undertake a new generation of laboratory experiments which will allow us to accurately determine the properties of deep-Earth materials under a new regime of P-T conditions.

The Mineral Physics Institute supports a laboratory for making acoustic measurements on polycrystalline samples using ultrasonic interferometry. We have a facility in the High Pressure Laboratory at Stony Brook University for making such measurements inside a Walker-type multi-anvil press at pressures up to 15 GPa. We support a similar, but smaller facility at the NSLS which uses X-ray diffraction for simultaneous measurement of pressure using diffraction standards. We also make use of another similar facility at the APS. In addition to high pressure experiments, we have also developed techniques for conducting benchtop acoustic experiments under ambient conditions. Using these facilities, we are able to extend the pressure and temperature (P-T) over which this experimental technique can be employed, as well as increase the accuracy of measurements taken in these experiments.

Accurate values of the high P-T velocities for key mantle minerals are used to clarify our view of mantle composition and thermal structure. This will greatly advance the technology of high pressure geophysics, and focus an effort on the accurate determination of the elastic properties of the most important mantle phases. In addition to mantle phases, other materials such as iron/light-element alloys and transition metals have been studied for their applications to materials science and the study of the cores of planetary bodies such as the Earth, Mars, and the Moon.

More information on the Ultrasonics Laboratory and the ultrasonics facilities available to the Mineral Physics Institute, please visit the Ultrasonics Group Website. The Ultrasonics Laboratory is overseen by Research Associate Professor Baosheng Li. For more information regarding the Ultrasonics Laboratory, or to discuss the analysis of your samples, please email him at Baosheng (dot) Li (at) sunysb (dot) edu.