TY - JOUR

T1 - P-V-T relation of MgO derived by simultaneous elastic wave velocity and in situ X-ray measurements

T2 - A new pressure scale for the mantle transition region

AU - Kono, Yoshio

AU - Irifune, Tetsuo

AU - Higo, Yuji

AU - Inoue, Toru

AU - Barnhoorn, Auke

AU - Suetsugu, Daisuke

AU - Bina, Craig

AU - Inoue, Toru

AU - Wiens, Douglas

AU - Jellinek, Mark

PY - 2010/11

Y1 - 2010/11

N2 - Simultaneous elastic wave velocity and in situ synchrotron X-ray measurements on polycrystalline MgO were carried out with a V/V0 between ∼0.9 and 1.0, which corresponds to the pressures up to 23.6GPa in our P-V-T relation of MgO, and temperatures up to 1650K using a multi-anvil apparatus. The experimentally observed adiabatic bulk modulus and unit-cell volume led to the first pressure-scale-independent P-V-T relation of MgO. We obtained a pressure derivative of the isothermal bulk modulus (K'T0=4.35(10)) and a volume dependent Grüneisen parameter (q0=1.5(5)), which reproduces the existing pressure-scale-independent data set (temperature dependence of elastic properties at ambient pressure and shock compression). Thus the present experimental and analytical procedure based on simultaneous elastic wave velocity and in situ X-ray diffraction measurements can give strong constraints on P-V-T equations of states (EoS) of minerals without any pressure scale. The present P-V-T EoS of MgO determined at pressure and temperature conditions comparable to the mantle transition region should be an important pressure scale to accurately determine the phase transition boundaries in this region. Application of the present pressure scale to the post-spinel transition boundary yields a transition pressure of 23.0GPa at 1873K, which is only marginally lower than that of the 660km discontinuity.

AB - Simultaneous elastic wave velocity and in situ synchrotron X-ray measurements on polycrystalline MgO were carried out with a V/V0 between ∼0.9 and 1.0, which corresponds to the pressures up to 23.6GPa in our P-V-T relation of MgO, and temperatures up to 1650K using a multi-anvil apparatus. The experimentally observed adiabatic bulk modulus and unit-cell volume led to the first pressure-scale-independent P-V-T relation of MgO. We obtained a pressure derivative of the isothermal bulk modulus (K'T0=4.35(10)) and a volume dependent Grüneisen parameter (q0=1.5(5)), which reproduces the existing pressure-scale-independent data set (temperature dependence of elastic properties at ambient pressure and shock compression). Thus the present experimental and analytical procedure based on simultaneous elastic wave velocity and in situ X-ray diffraction measurements can give strong constraints on P-V-T equations of states (EoS) of minerals without any pressure scale. The present P-V-T EoS of MgO determined at pressure and temperature conditions comparable to the mantle transition region should be an important pressure scale to accurately determine the phase transition boundaries in this region. Application of the present pressure scale to the post-spinel transition boundary yields a transition pressure of 23.0GPa at 1873K, which is only marginally lower than that of the 660km discontinuity.

KW - Elastic wave velocity

KW - Equation of state

KW - Mantle transition region

KW - MgO

UR - http://www.scopus.com/inward/record.url?scp=78649449277&partnerID=8YFLogxK

U2 - 10.1016/j.pepi.2010.03.010

DO - 10.1016/j.pepi.2010.03.010

M3 - Article

SN - 0031-9201

VL - 183

SP - 196

EP - 211

JO - Physics of the Earth and Planetary Interiors

JF - Physics of the Earth and Planetary Interiors

IS - 1-2

ER -