Table 3 Chemical composition of clinopyroxene. Units are weight percent of oxides and atoms per formula unit. X_Mg = Mg/(Mg + Fe)

Run

SPT1

EFSP2

SPT2

EFSP3

SPT3

SPT4

SPT5

P (GPa)

3.7

3.8

3.8

3.8

3.8

4.6

4.2

T (°C)

750

800

775

900

1000

700

900

SiO₂

55.80 (1.67)

54.11 (1.15)

56.52 (0.14)

54.22 (0.22)

55.20 (1.17)

54.67 (0.32)

54.97 (0.42)

Al₂O₃

12.83 (2.70)

6.54 (1.02)

8.44 (1.01)

13.14 (1.54)

12.00 (1.15)

11.34 (0.42)

16.25 (0.59)

FeO

2.75 (0.33)

2.08 (0.54)

2.53 (0.17)

3.65 (1.00)

1.89 (0.38)

3.05 (0.21)

1.81 (0.16)

MgO

8.58 (0.95)

13.56 (0.55)

11.38 (0.69)

8.71 (1.16)

11.07 (0.40)

10.23 (0.33)

8.29 (0.26)

CaO

14.73 (1.08)

21.14 (0.61)

18.00 (0.86)

13.39 (1.24)

17.21 (0.55)

18.04 (0.45)

13.92 (0.30)

Na₂O

5.71 (0.80)

1.99 (0.11)

4.03 (0.37)

5.80 (0.77)

3.79 (0.30)

3.66 (0.28)

5.50 (0.22)

Total

100.39 (1.07)

99.43 (1.45)

100.89 (0.15)

98.90 (0.86)

101.17 (1.36)

100.99 (0.21)

100.74 (0.47)

Si

1.961 (0.051)

1.952 (0.024)

1.991 (0.004)

1.948 (0.014)

1.928 (0.016)

1.928 (0.008)

1.909 (0.009)

Al

0.531 (0.110)

0.279 (0.047)

0.350 (0.041)

0.557 (0.067)

0.493 (0.041)

0.471 (0.017)

0.665 (0.024)

Fe²⁺

0.081 (0.010)

0.063 (0.017)

0.075 (0.005)

0.109 (0.030)

0.055 (0.011)

0.090 (0.006)

0.052 (0.004)

Mg

0.450 (0.053)

0.729 (0.021)

0.598 (0.038)

0.466 (0.061)

0.577 (0.029)

0.538 (0.018)

0.429 (0.014)

Ca

0.555 (0.045)

0.817 (0.016)

0.680 (0.034)

0.515 (0.046)

0.644 (0.032)

0.682 (0.018)

0.518 (0.012)

Na

0.389 (0.050)

0.139 (0.008)

0.275 (0.025)

0.404 (0.055)

0.257 (0.019)

0.250 (0.018)

0.370 (0.015)

X_Mg

0.848 (0.012)

0.921 (0.019)

0.888 (0.011)

0.812 (0.022)

0.913 (0.015)

0.857 (0.010)

0.891 (0.010)

Run

SPT6

FB6

SPT7

SPT8

SPT9

SPT10

P (GPa)

4.2

4.0

3.8

4.2

4.2

4.2

T (°C)

850

870

900

900

850

900

SiO₂

55.17 (0.52)

54.52 (0.99)

54.88 (0.80)

56.35 (0.44)

56.58 (0.61)

56.49 (0.44)

Al₂O₃

16.31 (1.22)

15.04 (2.26)

12.48 (2.07)

14.13 (0.45)

13.65 (1.25)

13.96 (1.50)

FeO

1.66 (0.16)

2.38 (0.69)

2.74 (0.70)

1.78 (0.12)

2.08 (0.62)

1.76 (0.16)

MgO

7.89 (0.29)

8.43 (0.63)

9.70 (1.04)

8.10 (0.28)

7.99 (0.25)

8.35 (0.98)

CaO

13.25 (0.44)

14.51 (0.83)

16.20 (1.00)

13.71 (0.41)

13.55 (0.46)

14.00 (1.00)

Na₂O

5.71 (0.39)

4.94 (0.42)

4.61 (0.52)

6.20 (0.38)

6.27 (0.31)

6.05 (0.45)

Total

99.99 (0.21)

99.82 (0.58)

100.61 (0.42)

100.27 (0.37)

100.12 (0.53)

100.61 (0.33)

Si

1.924 (0.020)

1.918 (0.037)

1.932 (0.026)

1.966 (0.009)

1.979 (0.020)

1.965 (0.007)

Al

0.670 (0.049)

0.623 (0.087)

0.518 (0.084)

0.581 (0.018)

0.562 (0.047)

0.572 (0.058)

Fe²⁺

0.048 (0.005)

0.070 (0.020)

0.081 (0.021)

0.052 (0.004)

0.061 (0.019)

0.051 (0.005)

Mg

0.410 (0.015)

0.442 (0.035)

0.509 (0.056)

0.421 (0.016)

0.417 (0.014)

0.433 (0.054)

Ca

0.495 (0.017)

0.547 (0.035)

0.611 (0.040)

0.512 (0.016)

0.508 (0.020)

0.522 (0.041)

Na

0.386 (0.027)

0.337 (0.029)

0.315 (0.034)

0.419 (0.025)

0.425 (0.022)

0.408 (0.028)

X_Mg

0.895 (0.008)

0.864 (0.035)

0.863 (0.034)

0.890 (0.007)

0.873 (0.034)

0.894 (0.010)