Single-crystal elasticity of the α and β of Mg2SiO4 polymorphs at high pressure

Chang Sheng Zha, Thomas S. Duffy, Robert T Downs, Ho Kwang Mao, Russell J. Hemley, Donald J. Weidner

Research output: Chapter in Book/Report/Conference proceedingChapter

11 Scopus citations


The full set of single-crystal elastic moduli of forsterite (α-Mg2SiO4) and wadsleyite (β-Mg2SiO4) were measured at pressures of 3-16 GPa and 0-14 GPa, respectively. For forsterite, the pressure derivatives of the bulk (K0‘s) and shear (G0') modulus are 4.2 ± 0.2 and 1.4 ± 0.1, respectively. For wadsleyite, the corresponding pressure derivatives are 4.3 ± 0.2 and 1.4 ± 0.2. These values are much lower than those reported in earlier, low-pressure studies for both materials. At the pressure of the 410-km seismic discontinuity, the room-temperature velocity increase across the a-p transition is 9.8% for compressional waves and 12.4% for shear waves. The results are consistent with an olivine fraction in the upper mantle of 30-50%.

Original languageEnglish (US)
Title of host publicationProperties of Earth and Planetary Materials at High Pressure and Temperature, 1998
PublisherBlackwell Publishing Ltd
Number of pages8
ISBN (Electronic)9781118664421
ISBN (Print)9780875900834
StatePublished - Jan 1 1997
Externally publishedYes

Publication series

NameGeophysical Monograph Series
ISSN (Print)0065-8448
ISSN (Electronic)2328-8779

ASJC Scopus subject areas

  • Geophysics

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