Table 2. Fractionation of calculated primitive magma, Site 990.
| Major elements |
Primitive magma | Fractionated from primitive | Unit 990-7 |
Fractionated from primitive | Unit 990-1 |
|---|---|---|---|---|---|
SiO2 |
48.45 |
51.17 |
51.19 |
51.69 |
51.83 |
TiO2 |
0.71 |
0.95 |
0.95 |
1.32 |
1.27 |
Al2O3 |
10.89 |
14.60 |
14.56 |
13.88 |
13.98 |
FeO total |
11.21 |
11.02 |
10.72 |
14.05 |
13.07 |
MnO |
0.16 |
0.21 |
0.20 |
||
MgO |
18.01 |
7.92 |
8.23 |
6.23 |
6.29 |
CaO |
8.88 |
11.91 |
11.87 |
10.00 |
10.48 |
Na2O |
1.54 |
2.07 |
2.06 |
2.35 |
2.49 |
K2O |
0.08 |
0.11 |
0.11 |
0.16 |
0.27 |
P2O5 |
0.06 |
0.08 |
0.08 |
0.12 |
0.13 |
Sum: |
99.99 |
99.82 |
100.00 |
99.80 |
100.00 |
Crystallized (%): |
30 |
54 |
|||
Assemblage: |
ol |
ol + pl + cpx |
|||
Pressure (kbar): |
7 |
7-3 |
3 |
||
Temperature (°C): |
1449 |
1202 |
1171 |
Notes: Primitive magma calculated by adding equilibrium olivine to Unit 990-7 until MgO = 18%. Fractionation calculations done with the program COMAGMAT at FMQ oxygen buffer and pressure as indicated. The fractionated from primitive column is the last step of olivine fractionation. At 31 mol% crystallized the fractionating assemblage is ol + pl + cpx. See text for detailed explanation.