SiO2 (wt%) | 54.90 | 54.96 | 55.53 | 55.03 | 55.61 | 55.56 | 55.34 | 55.32 |
TiO2 | 0.05 | 0.13 | 0.19 | 0.05 | 0.14 | 0.14 | 0.11 | 0.14 |
Al2O3 | 4.45 | 4.44 | 4.30 | 4.35 | 4.32 | 4.48 | 4.38 | 4.51 |
Cr2O3 | 0.28 | 0.31 | 0.28 | 0.32 | 0.26 | 0.32 | 0.28 | 0.33 |
FeOt | 6.04 | 6.40 | 6.02 | 6.23 | 6.12 | 6.12 | 6.06 | 6.25 |
MnO | 0.13 | 0.13 | 0.14 | 0.10 | 0.13 | 0.12 | 0.14 | 0.19 |
MgO | 33.15 | 32.99 | 33.16 | 33.39 | 32.97 | 33.07 | 33.27 | 33.53 |
CaO | 0.79 | 0.74 | 0.83 | 0.77 | 0.71 | 0.79 | 0.64 | 0.76 |
Na2O | 0.08 | 0.08 | 0.12 | 0.09 | 0.16 | 0.11 | 0.08 | 0.09 |
K2O | 0.00 | 0.01 | 0.02 | 0.02 | 0.01 | 0.00 | 0.04 | 0.00 |
Sum | 99.96 | 100.24 | 100.66 | 100.46 | 100.46 | 100.75 | 100.46 | 101.27 |
Fe2O3 (calc.) | 1.09 | 0.97 | 0.42 | 1.63 | 0.07 | 0.18 | 0.61 | 1.49 |
FeO (calc.) | 5.06 | 5.52 | 5.65 | 4.76 | 6.06 | 5.96 | 5.51 | 4.91 |
Sum (calc.) | 99.97 | 100.27 | 100.62 | 100.51 | 100.42 | 100.74 | 100.41 | 101.28 |
Si (a.p.f.u.) | 1.893 | 1.893 | 1.904 | 1.889 | 1.910 | 1.903 | 1.901 | 1.885 |
Aliv | 0.107 | 0.107 | 0.096 | 0.111 | 0.090 | 0.097 | 0.099 | 0.115 |
Alvi | 0.074 | 0.073 | 0.078 | 0.065 | 0.085 | 0.084 | 0.078 | 0.067 |
Ti | 0.001 | 0.003 | 0.005 | 0.001 | 0.004 | 0.004 | 0.003 | 0.003 |
Cr | 0.008 | 0.008 | 0.008 | 0.009 | 0.007 | 0.009 | 0.008 | 0.009 |
Fe3+ | 0.028 | 0.024 | 0.009 | 0.040 | 0.001 | 0.004 | 0.013 | 0.038 |
Fe2+ | 0.146 | 0.160 | 0.164 | 0.138 | 0.175 | 0.171 | 0.162 | 0.140 |
Mn | 0.004 | 0.004 | 0.004 | 0.003 | 0.004 | 0.004 | 0.004 | 0.006 |
Mg | 1.704 | 1.694 | 1.695 | 1.709 | 1.688 | 1.689 | 1.704 | 1.704 |
Ca | 0.029 | 0.027 | 0.030 | 0.028 | 0.026 | 0.029 | 0.023 | 0.028 |
Na | 0.006 | 0.005 | 0.008 | 0.006 | 0.010 | 0.007 | 0.006 | 0.006 |
Mg# | 92.1 | 91.4 | 91.2 | 92.5 | 90.6 | 90.8 | 91.3 | 92.4 |
Wo (mol.%) | 1.5 | 1.4 | 1.6 | 1.5 | 1.4 | 1.5 | 1.2 | 1.5 |
En | 89.2 | 88.7 | 89.1 | 89.1 | 89.1 | 89.0 | 89.4 | 88.9 |
Fs | 9.3 | 9.8 | 9.3 | 9.5 | 9.5 | 9.4 | 9.4 | 9.6 |