Composition | Center edge | |||||||||
Na2O | 0.07 | 0.02 | 0.02 | 0.07 | 0.02 | 0.00 | 0.02 | 0.02 | 0.00 | 0.00 |
FeO | 27.80 | 28.31 | 28.70 | 28.72 | 30.14 | 29.61 | 30.52 | 31.16 | 29.39 | 33.04 |
K2O | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.01 | 0.02 | 0.00 | 0.00 | 0.02 |
SiO2 | 36.99 | 36.91 | 37.04 | 36.94 | 36.94 | 36.66 | 37.01 | 36.92 | 35.63 | 37.18 |
MnO | 8.02 | 7.66 | 7.65 | 7.25 | 6.92 | 6.65 | 5.35 | 3.43 | 2.22 | 0.90 |
MgO | 1.27 | 1.28 | 1.33 | 1.36 | 1.47 | 1.45 | 1.50 | 1.64 | 1.68 | 2.09 |
CaO | 3.81 | 3.98 | 3.94 | 4.06 | 4.14 | 3.99 | 3.86 | 3.91 | 5.02 | 5.28 |
Al2O3 | 20.81 | 21.07 | 21.24 | 21.17 | 21.17 | 20.97 | 21.19 | 20.90 | 21.24 | 21.38 |
Total | 98.78 | 99.27 | 99.95 | 99.57 | 100.82 | 99.34 | 99.47 | 97.98 | 95.21 | 99.92 |
Na | 0.02 | 0.01 | 0.01 | 0.02 | 0.01 | 0.00 | 0.01 | 0.01 | 0.00 | 0.00 |
Fe | 3.80 | 3.86 | 3.88 | 3.90 | 4.06 | 4.04 | 4.14 | 4.27 | 4.12 | 4.44 |
K | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
Si | 6.05 | 6.01 | 5.99 | 5.99 | 5.95 | 5.98 | 6.00 | 6.05 | 5.97 | 5.97 |
Mn | 1.11 | 1.06 | 1.05 | 1.00 | 0.94 | 0.92 | 0.73 | 0.48 | 0.31 | 0.12 |
Mg | 0.31 | 0.31 | 0.32 | 0.33 | 0.35 | 0.35 | 0.36 | 0.40 | 0.42 | 0.50 |
Ca | 0.67 | 0.69 | 0.68 | 0.71 | 0.71 | 0.70 | 0.67 | 0.69 | 0.90 | 0.91 |
Al | 4.01 | 4.04 | 4.05 | 4.05 | 4.02 | 4.03 | 4.05 | 4.04 | 4.20 | 4.05 |
Total | 15.96 | 16.01 | 16.00 | 15.99 | 16.05 | 16.01 | 15.98 | 15.93 | 15.95 | 16.01 |