Constrain on elastic properties at high P and T of the minerals of the Earth's MTZ

利用超声干涉测量技术，研究了与深部地幔相关的高压高温条件下地幔过渡带矿物的纵波速度和横波速度。我们的实验室实验与地震观测结果的直接比较，使我们对地球深部地幔的结构有了初步的了解。研究结果表明，石榴石的化学变化很难解释低速区，这表明在660 km深度的不连续层附近，多重相变和/或转变可能是地震波分裂的原因。

The P- and S-wave velocities of mantle transition zone minerals were investigated by ultrasonic interferometry in situat simultaneous high pressure and high temperature relevant to the Earth’s deep mantle. The direct comparison of our laboratory experiments with seismic observations gives an original insight into the structure of the Earth’s deep mantle. Our results showed that chemical variation in garnet can hardly explain low velocity regions, which suggest that multiple phase transformation and/or transition could be responsible for splitting of seismic waves near the 660 km depth discontinuity.