Table 2 (continued).
| ALV-98 | JDF-D2 | |||||||
|---|---|---|---|---|---|---|---|---|
| (Fine and Stolper, 1986) |
(Metrich and Clocchiatti, 1989) | (This study) | (C.H.
Langmuir, pers comm., 1993) |
(This study) | ||||
| N = 50 | SD | N = 50 | SD | |||||
SiO2 |
49.53 |
49.70 |
49.57 |
0.38 |
50.80 |
50.56 |
0.22 |
|
TiO2 |
1.27 |
1.25 |
1.24 |
0.11 |
1.93 |
1.90 |
0.12 |
|
Al2O3 |
16.58 |
16.92 |
16.43 |
0.27 |
13.80 |
13.63 |
0.21 |
|
FeO* |
8.42 |
8.70 |
8.41 |
0.18 |
12.17 |
12.06 |
0.19 |
|
MnO |
0.14 |
0.15 |
0.18 |
0.03 |
0.22 |
0.23 |
0.04 |
|
MgO |
8.68 |
8.52 |
8.77 |
0.12 |
6.83 |
6.71 |
0.07 |
|
CaO |
11.81 |
11.05 |
12.06 |
0.13 |
10.80 |
10.84 |
0.12 |
|
Na2O |
2.88 |
3.05 |
2.81 |
0.03 |
2.77 |
2.69 |
0.03 |
|
K2O |
0.05 |
0.05 |
0.05 |
0.02 |
0.22 |
0.23 |
0.02 |
|
P2O5 |
0.06 |
ND |
0.07 |
0.03 |
0.23 |
0.22 |
0.03 |
|
Total |
99.42 |
99.56 |
99.59 |
99.77 |
99.08 |
|||
Notes: Unless noted, the analyses
were performed using an electron microprobe. XRF = X-ray fluorescence. SD = standard
deviation (2
). FeO* = total Fe as
(FeO + Fe2O3). ND = not determined.