Abstract
A laser-heated diamond-anvil cell that is capable of operating up to a pressure of 63 GPa, with X-ray diffraction facilities using a synchrotron radiation source at the SPring-8, has been developed to observe the compressibility of a hexagonal aluminous phase, [K0.15Na1.66Ca0.11Mg1.29Fe2+ 0.86Al3.13Ti0.09Si1.98] Σ9.27O12. The hexagonal aluminous phase is a potassium host mineral from the subducted oceanic crust in the Earth's lower mantle. A sample was heated using a YAG laser at each pressure increment to relax the deviatoric stress in the sample. X-ray diffraction measurements were carried out at 300 K using an angle-dispersive technique. Pressure was measured using an internal platinum pressure calibrant. The observed unit-cell volumes were used to obtain a third-order Birch–Murnaghan equation of state: unit-cell volume V o=185.94(±16) Å3, density ρ o=4.145 g/cm3, and bulk modulus K o=198(±3) GPa when the first pressure is derivative of the bulk modulus K ′ o is fixed to 4. The density of hexagonal aluminous phase is lower than that of coexisting Mg-perovskite in the subducted oceanic crust.
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Received: 14 December 2001 / Accepted: 26 June 2002
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Ono, S., Hirose, K., Isshiki, M. et al. Equation of state of hexagonal aluminous phase in basaltic composition to 63 GPa at 300 K. Phys Chem Min 29, 527–531 (2002). https://doi.org/10.1007/s00269-002-0263-5
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DOI: https://doi.org/10.1007/s00269-002-0263-5