Table 4 Chemical composition of garnet. Units are weight percent of oxides and atoms per formula unit. XMg = Mg/(Mg + Fe)
From: Melting carbonated epidote eclogites: carbonatites from subducting slabs
Run | EFSP2 | SPT2 | EFSP3 | SPT3 | SPT4 | SPT5 |
P (GPa) | 3.8 | 3.8 | 3.8 | 3.8 | 4.6 | 4.2 |
T (°C) | 800 | 775 | 900 | 1000 | 700 | 900 |
SiO2 | 41.02 (1.35) | 41.26 (0.30) | 40.41 (0.78) | 41.96 (0.29) | 40.37 (0.31) | 40.07 (0.09) |
Al2O3 | 22.84 (0.45) | 22.42 (0.23) | 22.38 (0.73) | 23.13 (0.38) | 22.91 (0.38) | 23.66 (0.38) |
Fe2O3 | 0.00 (0.00) | 0.00 (0.00) | 0.80 (0.96) | 0.33 (0.46) | 0.32 (0.31) | 0.41 (0.22) |
FeO | 10.69 (2.28) | 13.22 (1.00) | 16.82 (3.15) | 7.95 (0.81) | 11.39 (1.68) | 10.35 (0.77) |
MgO | 12.46 (1.31) | 9.82 (0.79) | 9.67 (1.59) | 14.43 (0.18) | 6.71 (1.18) | 8.47 (0.41) |
CaO | 12.17 (0.60) | 14.04 (0.32) | 10.48 (0.84) | 12.57 (0.44) | 19.28 (1.51) | 17.27 (0.24) |
Na2O | 0.02 (0.02) | 0.01 (0.01) | 0.09 (0.08) | 0.06 (0.04) | 0.02 (0.02) | 0.05 (0.06) |
Total | 99.21 (3.02) | 100.78 (0.57) | 100.65 (2.53) | 100.43 (0.80) | 101.00 (0.60) | 100.27 (0.33) |
Si | 3.023 (0.046) | 3.042 (0.009) | 3.014 (0.050) | 3.018 (0.018) | 2.992 (0.011) | 2.962 (0.013) |
Al | 1.984 (0.020) | 1.949 (0.012) | 1.967 (0.037) | 1.961 (0.021) | 2.001 (0.025) | 2.061 (0.024) |
Fe3+ | 0.000 (0.000) | 0.000 (0.000) | 0.044 (0.054) | 0.018 (0.024) | 0.018 (0.017) | 0.023 (0.012) |
Fe2+ | 0.658 (0.138) | 0.816 (0.064) | 1.051 (0.211) | 0.478 (0.047) | 0.706 (0.105) | 0.640 (0.050) |
Mg | 1.370 (0.159) | 1.079 (0.083) | 1.074 (0.175) | 1.548 (0.021) | 0.740 (0.125) | 0.934 (0.041) |
Ca | 0.961 (0.046) | 1.110 (0.030) | 0.837 (0.067) | 0.969 (0.037) | 1.532 (0.128) | 1.368 (0.019) |
Na | 0.003 (0.003) | 0.002 (0.001) | 0.012 (0.011) | 0.008 (0.005) | 0.003 (0.003) | 0.008 (0.009) |
XMg | 0.675 (0.071) | 0.569 (0.038) | 0.496 (0.079) | 0.758 (0.019) | 0.504 (0.062) | 0.585 (0.027) |
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 | 40.84 (0.60) | 40.80 (0.53) | 40.19 (0.42) | 40.58 (0.42) | 40.34 (0.41) | 40.14 (0.23) |
Al2O3 | 23.19 (0.90) | 22.81 (0.44) | 22.92 (0.42) | 23.50 (0.18) | 22.09 (0.56) | 22.93 (0.25) |
Fe2O3 | 0.27 (0.58) | 0.00 (0.00) | 0.42 (0.54) | 0.38 (0.40) | 0.03 (0.10) | 0.26 (0.22) |
FeO | 10.85 (0.87) | 10.79 (1.92) | 14.20 (1.31) | 10.99 (0.61) | 15.28 (1.58) | 13.06 (1.53) |
MgO | 8.11 (0.40) | 8.68 (2.18) | 7.63 (0.72) | 8.42 (0.34) | 5.54 (0.71) | 7.50 (1.12) |
CaO | 17.45 (0.62) | 16.58 (1.35) | 15.38 (0.75) | 16.92 (0.52) | 17.00 (1.08) | 16.11 (0.29) |
Na2O | 0.08 (0.03) | 0.06 (0.04) | 0.07 (0.06) | 0.04 (0.04) | 0.11 (0.10) | 0.06 (0.04) |
Total | 100.79 (0.61) | 99.73 (0.67) | 100.81 (0.68) | 100.83 (0.37) | 100.39 (0.38) | 100.06 (0.18) |
Si | 3.012 (0.038) | 3.032 (0.031) | 2.991 (0.024) | 2.984 (0.026) | 3.040 (0.024) | 2.989 (0.007) |
Al | 2.016 (0.075) | 1.997 (0.017) | 2.010 (0.030) | 2.036 (0.016) | 1.962 (0.042) | 2.013 (0.009) |
Fe3+ | 0.015 (0.032) | 0.000 (0.000) | 0.024 (0.030) | 0.021 (0.022) | 0.002 (0.006) | 0.015 (0.012) |
Fe2+ | 0.669 (0.052) | 0.672 (0.124) | 0.884 (0.084) | 0.676 (0.037) | 0.963 (0.106) | 0.814 (0.099) |
Mg | 0.891 (0.044) | 0.960 (0.224) | 0.845 (0.076) | 0.922 (0.038) | 0.621 (0.075) | 0.832 (0.117) |
Ca | 1.379 (0.054) | 1.321 (0.118) | 1.226 (0.059) | 1.333 (0.040) | 1.372 (0.084) | 1.286 (0.026) |
Na | 0.012 (0.005) | 0.009 (0.006) | 0.010 (0.008) | 0.005 (0.006) | 0.016 (0.015) | 0.008 (0.005) |
XMg | 0.566 (0.027) | 0.583 (0.096) | 0.483 (0.042) | 0.570 (0.021) | 0.392 (0.049) | 0.501 (0.067) |