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Isothermal compressibility of hydrous ringwoodite and its relation to the mantle discontinuities
Author(s) -
Yusa Hitoshi,
Inoue Toru,
Ohishi Yasuo
Publication year - 2000
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 - 10.1029/1999gl011032
Subject(s) - ringwoodite , bulk modulus , diamond anvil cell , classification of discontinuities , compressibility , isothermal process , geology , mantle (geology) , anhydrous , equation of state , mineralogy , thermodynamics , hydrostatic equilibrium , materials science , high pressure , geochemistry , chemistry , physics , mathematical analysis , mathematics , organic chemistry , quantum mechanics
High pressure X‐ray diffraction experiments of hydrous ringwoodite, containing 2.8 ± 0.2 wt% H 2 O, have been carried out by using X‐rays from a synchrotron radiation source with a diamond anvil cell under hydrostatic pressure up to 6 GPa. The isothermal bulk modulus (K 0 ) was determined to be 148 ± 1 GPa with the pressure derivative (K′ 0 ) fixed to 5 using the Birch‐Murnaghan equation of state. This value is almost 80% of that of anhydrous ringwoodite. The relations of the bulk modulus and zero pressure volumes (V 0 ) with H 2 O content are estimated within the solid solution range. Combining the present results with recent seismological data, the nature of the 520 km and 660 km seismic discontinuities is discussed.