SUMMARY

Study on elastic velocity of hydrous phases at high pressure of subduction zone

Phan Thiên Hương

Ultrasonic wave propagation velocities of polycrystalline aggregates of the dense hydrous magnesium silicate phase (DHMS) clinohumite (Mg₉Si₄O₁₆(OH)₂) has been measured at high pressure and room temperature conditions. The starting materials prepared by a sol-gel technique and synthesis experiments were conducted with a rocking piston cylinder and multi-anvil apparatus to produce homogenous fine-grained polycrystalline aggregates. The recovered specimens are homogeneous with small grain sizes of less than 20 micrometers, free of microscopic cracks, devoid of preferred orientation, and with bulk densities of »99% of the theoretical value. Experiments have been performed in the pressure range of from 1 to 11 GPa at room temperature. Elastic moduli and their derivatives of clinohumite were derived and result: K_S = 119(2) GPa, K’_S = 4.8(1), G = 77(1) GPa and G’ = 1.9(2).

Người biên tập: GS.TSKH Mai Thanh Tân