SiO2 (wt%) | 51.88 | 51.99 | 52.47 | 51.76 | 52.25 | 51.85 | 51.97 | 52.44 |
TiO2 | 0.51 | 0.46 | 0.42 | 0.54 | 0.52 | 0.46 | 0.42 | 0.52 |
Al2O3 | 6.70 | 6.53 | 6.56 | 6.71 | 6.50 | 6.67 | 6.65 | 6.85 |
Cr2O3 | 0.78 | 0.73 | 0.74 | 0.75 | 0.67 | 0.77 | 0.75 | 0.72 |
Fe2O3 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
MnO | 0.10 | 0.10 | 0.14 | 0.13 | 0.09 | 0.10 | 0.11 | 0.08 |
MgO | 15.21 | 15.50 | 15.54 | 15.47 | 15.39 | 15.45 | 15.39 | 15.35 |
CaO | 20.76 | 20.26 | 20.55 | 20.26 | 20.52 | 20.51 | 20.33 | 20.55 |
Na2O | 1.64 | 1.61 | 1.70 | 1.72 | 1.75 | 1.70 | 1.57 | 1.73 |
Sum | 100.45 | 100.07 | 100.92 | 100.29 | 100.63 | 100.53 | 100.01 | 101.20 |
Fe2O3 (calc.) | 1.88 | 1.47 | 1.76 | 2.23 | 1.93 | 2.40 | 1.20 | 1.58 |
FeO (calc.) | 0.96 | 1.41 | 1.04 | 0.72 | 1.01 | 0.61 | 1.61 | 1.36 |
Sum (calc.) | 100.45 | 100.07 | 100.92 | 100.29 | 100.63 | 100.53 | 100.01 | 101.20 |
T-site |
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Si (a.p.f.u.) | 1.866 | 1.875 | 1.875 | 1.862 | 1.874 | 1.862 | 1.875 | 1.871 |
Al iv | 0.134 | 0.125 | 0.125 | 0.138 | 0.126 | 0.138 | 0.125 | 0.129 |
Sum | 2.000 | 2.000 | 2.000 | 2.000 | 2.000 | 2.000 | 2.000 | 2.000 |
M1-site |
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Mg | 0.737 | 0.737 | 0.741 | 0.738 | 0.739 | 0.740 | 0.733 | 0.728 |
Fe2+ | 0.029 | 0.039 | 0.028 | 0.020 | 0.027 | 0.017 | 0.045 | 0.037 |
Alvi | 0.150 | 0.152 | 0.152 | 0.147 | 0.149 | 0.145 | 0.158 | 0.159 |
Fe3+ | 0.047 | 0.039 | 0.047 | 0.060 | 0.052 | 0.065 | 0.032 | 0.043 |
Ti | 0.014 | 0.012 | 0.011 | 0.014 | 0.014 | 0.013 | 0.011 | 0.014 |
Cr | 0.022 | 0.021 | 0.021 | 0.021 | 0.019 | 0.022 | 0.021 | 0.020 |
Sum | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 |
M2-site |
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Ca | 0.800 | 0.783 | 0.787 | 0.781 | 0.788 | 0.789 | 0.786 | 0.785 |
Na | 0.115 | 0.112 | 0.118 | 0.120 | 0.122 | 0.119 | 0.110 | 0.120 |
Mg | 0.079 | 0.097 | 0.087 | 0.092 | 0.084 | 0.087 | 0.095 | 0.088 |
Fe2+ | 0.003 | 0.005 | 0.003 | 0.002 | 0.003 | 0.002 | 0.006 | 0.004 |
Mn | 0.003 | 0.003 | 0.004 | 0.004 | 0.003 | 0.003 | 0.003 | 0.002 |
Sum | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 |
V(cell) | 437.66 | 437.48 | 437.42 | 437.38 | 437.48 | 437.48 | 437.53 | 437.48 |
V(M1) | 11.39 | 11.40 | 11.39 | 11.39 | 11.39 | 11.39 | 11.39 | 11.37 |
AlVI/AlIV | 1.1 | 1.2 | 1.2 | 1.1 | 1.2 | 1.0 | 1.3 | 1.2 |
Mg# | 96.6 | 95.2 | 96.4 | 97.5 | 96.5 | 97.8 | 94.4 | 95.3 |
Cr# | 7.2 | 7.0 | 7.0 | 7.0 | 6.5 | 7.2 | 7.0 | 6.6 |
Wo (mol.%) | 44.8 | 46.5 | 44.1 | 46.6 | 46.5 | 44.9 | 44.7 | 45.6 |
En | 37.6 | 38.5 | 41.0 | 38.7 | 39.2 | 39.0 | 38.5 | 38.0 |
Fs | 17.6 | 15.0 | 14.8 | 14.7 | 14.3 | 16.1 | 16.8 | 16.4 |