Sound Velocity Of (Mg$_{0.92}$, Fe$_{0.08}$)Sio$_{3}$ Perovskite up to 140 Shock Pressure and Its Geophysical Implications

New experimental data of compressional sound velocity for polycrystalline enstitate (Mg$_{0.92}$, Fe$_{0.08})$SiO$_{3 }$initial specimens were measured up to 140 GPa shock pressure using the optical analyzer techniques. The results confirm the discontinuity and negative jump of compressional sound velocity between 70-85GPa. This pressure range is comparable with that of the HS to LS transition of iron in (Mg$_{0.92}$, Fe$_{0.08})$SiO$_{3}$ Perovskite. Moreover, the estimated phase boundary dT/dP, 66$\sim $92 K/GPa, is consistent with that of spin transition estimation. The corresponding depth in the lower mantle of 70-85GPa just is 1600-1800km, so, the radial anomaly of seismic wave velocity in this region of the lower mantle is possible a result of solid to solid structure transition of (Mg$_{0.92}$, Fe$_{0.08})$SiO$_{3}$ Perovskite.