Back to article

Figures and tables

Rapid decrease of MgAlO2.5 component in bridgmanite with pressure

Z. Liu1,

1Bayerisches Geoinstitut, University of Bayreuth, 95440 Bayreuth, Germany

T. Ishii1,

1Bayerisches Geoinstitut, University of Bayreuth, 95440 Bayreuth, Germany

T. Katsura1

1Bayerisches Geoinstitut, University of Bayreuth, 95440 Bayreuth, Germany

Affiliations  |  Corresponding Author  |  Cite as  |  Funding information

Liu, Z., Ishii, T., Katsura, T. (2017) Rapid decrease of MgAlO2.5 component in bridgmanite with pressure. Geochem. Persp. Let. 5, 12–18.

Bayerisches Geoinstitut Visitor’s Program and research grants BMBF (05K13WC2, 05K13WC2) and DFG (KA3434/3-1, KA3434/7-1, KA3434/8-1, KA3434/9-1).

Geochemical Perspectives Letters v5  |  doi: 10.7185/geochemlet.1739
Received 10 May 2017  |  Accepted 8 September 2017  |  Published 12 October 2017
Copyright © 2017 European Association of Geochemistry




Figure 1 XRD patterns of En90Brm10 subjected to (a) 27, (b) 35 and (c) 40 GPa and at 2000 oK. Number in parentheses represents the index of bridgmanite. Question marks denote unidentified peaks. Asterisk denotes the probable (200) peak of periclase.
Back to article | Download in Powerpoint


Figure 2 Representative BSE images of En90Brm10 subjected to (a) 27 GPa, (b) 35 and (c) 40 GPa and 2000 oK.
Back to article | Download in Powerpoint


Table 1 Experimental conditions, run products, and phase compositions.
Start CompPhasesMgOAl2O3SiO2TotalOMgAlSi
IRIS333 (27 GPa, 2000 °K; 3 hours)








En90Brm10Brg [n = 40]39.82 (23)5.13 (15)55.92 (24)100.86 (14)2.973 (4)0.979 (5)0.100 (3)0.922 (4)
En95Cor5Brg [n = 26]37.93 (22)5.11 (12)56.31 (3)99.35 (55)2.998 (2)0.952 (5)0.101 (2)0.948 (4)
IRIS357 (35 GPa, 2000 °K; 2 hours)








En90Brm10Brg [n = 52]39.11 (52)5.19(13)56.38 (45)100.69 (25)2.984 (7)0.970 (13)0.102 (2)0.938 (7)
IRIS351 (40 GPa, 2000 °K *; 3 hours)








En90Brm10Brg [n = 55]38.01 (40)5.09 (12)56.01 (46)99.11 (65)2.995 (4)0.955 (8)0.101 (2)0.944 (4)
En95Cor5Brg [n = 20]38.44 (32)5.12 (16)57.37 (55)100.92 (72)2.999 (3)0.949 (6)0.100 (3)0.950 (3)

Oxide analyses are reported in wt. %. n: number of analysis points.
*: temperature was evaluated from a calibrated power curve derived from a lower temperature of 1500 °K.
Number in parentheses represents standard deviation for the last digit(s). Abbreviation: Brg, bridgmanite.

Back to article | Download in Excel


Figure 3 Plots of (a) oxygen number, (b) Mg/Si ratio, and (c) Al ratio in A and B sites (AlB/AlA) in bridgmanite for En90Brm10 and En95Cor5 versus pressure. The black lines represent the compositions associated with the oxygen-vacancy substitution mechanism (OVM) and charge-coupled substitution mechanism (CCM) for bridgmanite. The red line is the least squares fitting (Mg/Si = Aexp(–P/B) + C, where P is pressure) of the present data.
Back to article | Download in Powerpoint


Back to article

Supplementary Figures and Tables


Table S-1 Chemical compositions of the starting glass material.
Starting materialMgOAl2O3SiO2TotalOMgAlSi
En90Brm10 (n = 25)39.49 (18)5.11 (5)55.08 (37)99.68 (40)2.969 (3)0.982 (6)0.101 (1)0.918 (3)
En95Cor5 (n = 15)38.42 (29)5.10 (5)57.47 (48)100.99 (52)3.002 (7)0.948 (9)0.100 (2)0.951 (7)
En100 (n = 12)40.39 (50)59.39 (60)99.78 (36)2.994 (7)1.006 (14)0.994 (7)

Oxide analyses are reported in wt. %. n: number of analysis points.
Number in parentheses represents standard deviation and is placed in the last digit (s).

Back to article | Download in Excel


Figure S-1 The schematic illustration of (a) 7/3 and (b) 5.7/1.5 cell assembly for high pressure and high temperature experiments.
Back to article | Download in Powerpoint


Figure S-2 Pressure calibrations of 7/3 (a) and 5.7/1.5 (b) cell assembly in IRIS-15 at 300 and 2000 oK, respectively.
Back to article | Download in Powerpoint


Table S-2 The experimental condition and composition of MgSiO3 bridgmanite.
Starting materialPhasesMgOAl2O3SiO2TotalOMgAlSi
IRIS333 (27 GPa, 2000 °K; 3 hours)
En100Brg (n = 25)40.39 (50)59.39 (60)99.78 (36)2.996 (3)1.006 (9)0.995(7)

Oxide analyses are reported in wt. %. n: number of analysis points.
Number in parentheses represents standard deviation and is placed in the last digit (s).
Abbreviation: Brg, bridgmanite.

Back to article | Download in Excel


Figure S-3 XRD patterns of the recovered sample for En95Cor5 composition at 27 (a) and 40 GPa (b) under 2000 oK, respectively. Number in parentheses represents the index of bridgmanite.
Back to article | Download in Powerpoint


Figure S-4 Unit cell volumes of bridgmanite along the system MgSiO3–Al2O3 and MgSiO3–MgAlO2.5 in the present and previous studies. The solid line presents the linear fitting results on values for bridgmanite along the system MgSiO3-Al2O3 (Liu et al., 2016).
Back to article | Download in Powerpoint


Table S-3 Elastic properties of minerals related with Eq. S-2 used for thermodynamic calculations.
PhaseMgSiO3-BrgMg0.95Al0.1Si0.95O3-BrgMgAl0.1Si0.9O2.95-BrgMgO
V0 (cm3/mol)24.44 (1)a24.54 (1)e24.50 (1)f11.27 (1)h
ΔH0(KJ/mol)10.79 (196)b16.44 (88)b10.24 (428)f36.48 (50)i
ΔS0(KJ/mol)0.063b0.058b0.073f0.026i
KT298 (GPa)256.7 (15)a239 (1)e259 (8)g160.9h
KT'4.09 (6)a4e4g4.35 (10)h
(δKT/δT)P (GPa/°K)­0.035 (2)c-0.057 (1)e-0.057 (1)*-0.0272h
αT= a0+a1T+a2T2 (°K-1)



a0 ×1051.982d2.08 (26)e2.08 (26)*3.38i
a1 ×1080.818d2.21 (67)e2.21 (67)*12.52i
a2 ×10-4.740d00-19.13i
CP= A+BT+CT-2 (°K-1)



A×10-21.769d1.769#1.769*0.66i
B×10-3-1.565d-1.565#-1.565*-0.36i
C ×10-6000-0.61i

a: Tange et al. (2012)
b: Akaogi and Ito (1999)
c: Katsura et al. (2009)
d: Funamori et al. (1996)
e: Zhand and Wiedner (1999)
f: Navrotsky et al. (2003)
g: Walter et al. (2006)
h: Kono et al. (2010)
i: Kojitani et al. (2012)
#: the same value with that of MgSiO3-Brg.
*: the same value with that of Mg0.95Al0.1Si0.95O3-Brg.
Abbreviation: Brg: bridgmanite.
Number in parentheses represents standard deviation and is placed in the last digit (s).

Back to article | Download in Excel


Figure S-5 The calculated molar volume change of Eq. S-2 in the text along 300 and 2000 °K, respectively.
Back to article | Download in Powerpoint