P‐V‐T relations of wadsleyite determined by in situ X‐ray diffraction in a large‐volume high‐pressure apparatus

Abstract

[1] The volume of Mg 2 SiO 4 wadsleyite has been precisely measured at pressures of 11 to 20 GPa and temperatures of 300 to 2100 K by means of in situ X-ray diffraction in a multi-anvil apparatus. The fixed isothermal bulk modulus K T0 = 169.2 GPa gives its pressure derivative K 0 T0 = 4.1(1). The fixed Debye temperature q 0 = 814 K gives a Grüneisen parameter at ambient pressure g 0 = 1.64(2) and its logarithmic volume dependence q = 1.5(1). The pressure derivative of the isothermal bulk modulus, Anderson-Grüneisen parameter and thermal expansion coefficient at ambient pressure are found to be (@K T /@T ) P = À0.021(1) GPa/K, d T = 5.5(2), a 0 = 2.31(3) Â 10 À5 + 1.18(3) Â 10 À8 (T À 300) K À1. The pressure and volume dependence of thermal expansion coefficient of wadsleyite is the smallest among those of the mantle minerals. The adiabatic temperature gradient in the upper part of the mantle transition zone is 0.34(1) K/km. Citation: Katsura, T., et al.(2009), P-V-T relations of wadsleyite determined by in situ X-ray diffraction in a large-volume high-pressure apparatus, Geophys.

Comparative compressibility of hydrous wadsleyite and ringwoodite: Effect of H2O and implications for detecting water in the transition zone

“…These differences remain essentially constant in the depth range 410–520 km for both cases. However, if we remove the constraint imposed from this study that K 0 ′ of anhydrous and hydrous wadsleyite are similar and instead compare V Φ for anhydrous wadsleyite with K 0 ′ ~4 [ Katsura et al ., ; Wang et al ., ] and V Φ for hydrous wadsleyite with K 0 ′ = ~5 [ Holl et al ., ; Mao et al ., ], a velocity crossover occurs at a depth of ~350 km, implying that hydrous wadsleyite would be the faster phase at transition zone pressures, which seems highly unlikely.…”

“…References: (1) Li and Gwanmesia , [], (2) Katsura et al . [], (3) Zha et al . [], (4) Hazen et al .…”

Hydration effects on crystal structures and equations of state for silicate minerals in the subducting slabs and mantle transition zone

“…Yusa and Inoue, 1997;Yusa et al, 2000;Ross and Crichton, 2001;Crichton and Ross, 2002;Kudoh et al, 2002;Kuribayashi et al, 2003Kuribayashi et al, , 2004Kuribayashi et al, , 2008Smyth et al, 2004;Manghnani et al, 2005Manghnani et al, , 2013Holl et al, 2006Holl et al, , 2008Ganskow et al, 2010; al., 2010, 2012). On the other hand, some studies have been conducted for the P-V-T EoS of anhydrous forsterite, wadsleyite, and ringwoodite (Meng et al, 1993(Meng et al, , 1994Guyot et al, 1996;Li et al, 2001;Katsura et al, 2004Katsura et al, , 2009aKatsura et al, , 2009bCouvy et al, 2010). Some high-temperature measurements (at ambient pressure) have also been carried out for these DHMS and hydrous NAMs phases (Pawley et al, 1995: Inoue et al, 2004Ye et al, 2009Ye et al, , 2011Ye et al, , 2012Ye et al, , 2013Ye et al, , 2015, which are useful for establishing simultaneous P-V-T EoSs of these hydrous silicate minerals in the future.…”

Reactive Preservation of Carbonate in Earth's Mantle Transition Zone

“…At ambient conditions, the volume change of the cation exchange reaction from calcite and Mg-bridgmanite to magnesite and Ca-perovskite is -5.95 cc/mol (Biellmann et al, 1993), and that of reaction (1) is -2.54 cc/mol. The bulk moduli of aragonite, magnesite, wadsleyite, CaSi-perovskite, and periclase at 1 bar and 300 K are 66, 108, 173, and 232, and 160 GPa, respectively (Fiquet et al, 2002;Katsura et al, 2009;Litasov et al, 2017;Shim et al, 2000). Because the products CaSiO 3 perovskite and magnesite are less compressible than the reactants wadsleyite and aragonite, respectively, the reaction volume becomes less negative at higher pressures.…”