SiO2 (wt%) | 40.96 | 41.47 | 41.05 | 41.13 | 40.93 | 40.94 |
Al2O3 | 0.02 | 0.02 | 0.02 | 0.05 | 0.01 | 0.01 |
FeO | 9.77 | 10.12 | 9.89 | 10.11 | 9.95 | 9.98 |
MnO | 0.16 | 0.16 | 0.12 | 0.16 | 0.12 | 0.16 |
MgO | 49.26 | 49.53 | 48.83 | 49.41 | 49.24 | 49.38 |
CaO | 0.07 | 0.05 | 0.02 | 0.06 | 0.05 | 0.01 |
NiO | 0.37 | 0.33 | 0.34 | 0.41 | 0.25 | 0.36 |
Sum | 100.61 | 101.68 | 100.27 | 101.33 | 100.55 | 100.84 |
Si (a.p.f.u.) | 0.998 | 1.001 | 1.004 | 0.997 | 0.999 | 0.997 |
Al | 0.000 | 0.000 | 0.000 | 0.001 | 0.000 | 0.000 |
Fe2+ | 0.199 | 0.204 | 0.202 | 0.205 | 0.203 | 0.203 |
Mn | 0.003 | 0.003 | 0.003 | 0.003 | 0.003 | 0.003 |
Mg | 1.790 | 1.782 | 1.780 | 1.785 | 1.791 | 1.792 |
Ca | 0.002 | 0.001 | 0.001 | 0.001 | 0.001 | 0.000 |
Ni | 0.007 | 0.006 | 0.007 | 0.008 | 0.005 | 0.007 |
Fa (%) | 10.0 | 10.3 | 10.2 | 10.3 | 10.2 | 10.2 |
Fo | 90.0 | 89.7 | 89.8 | 89.7 | 89.8 | 89.8 |