Sound Velocity Measurement of Minerals and Rocks at Mantle Transition Zone Conditions Using Ultrasonic and Multianvil Techniques

Experimental studies of the sound velocity of minerals of the mantle are crucial for understanding the compositions and properties of the Earth's deep interiors. The ultrasonic technique has been globally used in the multianvil press for velocity measurements of various mantle minerals at relevant P-T conditions of the mantle transition zone. However, the ultrasonic velocity measurements in multianvil in China have been limited to < 6 GPa conditions in the past. Recently, we developed a new ultrasonic velocity measurement system in a 1 000 t Walker type multianvil press installed in China University of Geosciences (Wuhan) and measured the velocities of an Mg₂SiO₄ wadsleyite polycrystalline sample up to 18 GPa. The results are comparable with those of previous ultrasonic studies. For the first time in China, the sound velocity measurement was taken at high pressure conditions of the mantle transition zone in a multianvil with ultrasonic techniques, bridging the gap between the domestic and the international advanced level. The technique would provide not only experimental constraints on the interpretation of the geophysical observation beneath China and surrounding regions, but also experimental supports for the studies on the elastic properties of minerals/rocks and condensed materials in China.