In situ Ultrasonic Velocity Measurements Across the Olivine-spinel Transformation in Fe2Si04

Journal Article · Fri Jan 01 04:00:00 EST 2010 · American Mineralogist

DOI:https://doi.org/10.2138/am.2010.3369· OSTI ID:1019701

Liu, Q; Liu, W; Whitaker, M; Wang, L; Li, B

Compressional (P) and shear (S) wave velocities across the olivine-spinel transformation in Fe{sub 2}SiO{sub 4} were investigated in situ using combined synchrotron X-ray diffraction, X-ray imaging, and ultrasonic interferometry up to 5.5 GPa along the 1173 K isotherm. The onset of the spinel to olivine transformation at 4.5 GPa and olivine to spinel transition for Fe{sub 2}SiO{sub 4} at 4.8 GPa was concurrently observed from X-ray diffraction, the amplitude of the ultrasonic signals, the calculated velocities, and the ratio of P and S wave velocities (v{sub P}/v{sub S}). No velocity softening was observed prior to the fayalite to spinel transition. The velocity contrasts across the Fe{sub 2}SiO{sub 4} spinel to fayalite phase transition are derived directly from the measured velocities, which are 13 and 12% for P and S waves, respectively, together with a density contrast of 9.4%. A comparison with literature data indicates that the changes in compressional-wave velocity and density across the olivine-spinel transformation in Fe{sub 2}SiO{sub 4} are comparable to those with different iron concentrations in the (Mg,Fe){sub 2}SiO{sub 4} solid solution, whereas the shear wave velocity contrast decreases slightly with increasing iron concentration.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1019701
• Report Number(s): BNL--95547-2011-JA
• Journal Information: American Mineralogist, Journal Name: American Mineralogist Journal Issue: 7 Vol. 95; ISSN AMMIAY; ISSN 0003-004X
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
AMPLITUDES
INTERFEROMETRY
IRON
ISOTHERMS
OLIVINE
PHASE TRANSFORMATIONS
S WAVES
SHEAR
SOLID SOLUTIONS
SPINELS
SYNCHROTRONS
TRANSFORMATIONS
ULTRASONIC WAVES
VELOCITY
X-RAY DIFFRACTION
national synchrotron light source