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Acoustic velocities of pure and iron‐bearing magnesium silicate perovskite measured to 25 GPa and 1200 K
Author(s) -
Chantel Julien,
Frost Daniel J.,
McCammon Catherine A.,
Jing Zhicheng,
Wang Yanbin
Publication year - 2012
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2012gl053075
Subject(s) - silicate , materials science , bulk modulus , mineralogy , silicate perovskite , perovskite (structure) , analytical chemistry (journal) , adiabatic process , shear modulus , thermodynamics , geology , composite material , chemistry , crystallography , physics , organic chemistry , chromatography
Ultrasonic interferometry measurements in conjunction with in situ X‐ray techniques have been used to measure compressional and shear wave velocities and densities of MgSiO 3 perovskite (Mg‐Pv) and Mg 0.95 Fe 0.04 2+ Fe 0.01 3+ SiO 3 perovskite ((Mg, Fe)‐Pv) in the multianvil at pressures up to 25 GPa and temperatures to 1200 K. Data for Mg‐Pv are consistent with previous studies and the (Mg, Fe)‐Pv sample has almost identical shear properties to Mg‐Pv. The adiabatic bulk modulus, Ks , for (Mg, Fe)‐Pv, however, is found to be substantially lower than Mg‐Pv, with a refined value of 236 GPa and a pressure derivative of 4.7. It is proposed that this low K S value result from a change in the elasticity of Fe‐bearing perovskite at low pressures <30 GPa. High temperature data are consistent with recent models and it is shown that the obtained elastic properties of (Mg, Fe)‐Pv are not inconsistent with a lower mantle of bulk silicate Earth composition.