Table 3
Representative analyses of the main phases of the SBMS. When several analyses are available for a mineral species, the average composition and the corresponding structural formula are given. For vermiculite and smectite, the structural formulae were not determined due to the great diversity of the microprobe analyses in our sample collection. Average values are calculated on the basis of: a) 12 analyses from four samples; b) 29 analyses from two samples; c) seven analyses from three samples; d) five analyses from two samples; e) nine analyses from four samples; f) 19 analyses from three samples; g) single analysis; h) three analyses from one sample; i) single analysis; j) five analyses from two samples; k) 46 analyses from six samples; l) six analyses from two samples.
| |
Sapphirine |
Enstatite |
Aluminous spinel |
Mg-amphibole (anthophyllite) |
| |
|
|
|
|
| |
a |
Range |
b |
Range |
c |
Range |
d |
Range |
| SiO2 |
13.37 |
12.79–13.7 |
56.40 |
55.49–57.29 |
0.02 |
0.00–0.06 |
56.03 |
55.51–56.91 |
| TiO2 |
0.09 |
0.02–0.13 |
0.05 |
0.00–0.11 |
0.02 |
0.00–0.07 |
0.13 |
0.08–0.18 |
| Al2O3 |
62.95 |
59.49–64.85 |
2.51 |
1.89–3.48 |
67.06 |
65.10–68.65 |
4.93 |
4.90–5.25 |
| CaO |
0.04 |
0.00–0.06 |
– |
– |
0.08 |
0.04–0.13 |
0.00 |
0.00–0.01 |
| FeO |
3.87 |
2.93–6.73 |
6.77 |
4.97–7.88 |
10.32 |
8.15–13.22 |
6.18 |
5.64–6.69 |
| MnO |
0.01 |
0.00–0.04 |
0.08 |
0.00–0.16 |
0.02 |
0.00–0.07 |
0.02 |
0.00–0.06 |
| MgO |
19.44 |
18.90–19.81 |
33.94 |
32.29–35.34 |
22.33 |
20.78–23.45 |
29.24 |
28.65–29.55 |
| CaO |
0.04 |
0.00–0.06 |
0.14 |
0.05–0.21 |
0.04 |
0.02–0.05 |
0.59 |
0.44–0.73 |
| Na2O |
0.01 |
0.00–0.05 |
0.04 |
0.00–0.19 |
0.00 |
0.00–0.02 |
0.47 |
0.38–0.58 |
| K2O |
0.01 |
0.00–0.02 |
0.02 |
0.00–0.05 |
0.00 |
0.00–0.01 |
0.01 |
0.00–0.02 |
| NiO |
0.01 |
0.00–0.02 |
– |
– |
0.00 |
0.00–0.01 |
0.00 |
0.00–0.00 |
| P2O5 |
0.02 |
0.00–0.04 |
– |
– |
0.00 |
0.00–0.01 |
0.01 |
0.00–0.04 |
|
|
|
|
|
|
|
|
|
| Total |
99.86 |
|
99.96 |
|
99.89 |
|
97.60 |
|
| Representative formulae |
|
| Cations |
Basis of 20(O) |
Basis of 6(O) |
Basis of 4(O) |
Basis of 23(O) |
| Si |
1.58 |
1.95 |
0.00 |
7.52 |
| Ti |
0.00 |
0.00 |
0.00 |
0.01 |
| Al |
8.87 |
0.10 |
1.98 |
0.78 |
| Cr |
0.00 |
0.00 |
0.00 |
0.00 |
| Fe3+ |
0.00 |
0.00 |
0.00 |
0.17 |
| Fe2+ |
0.30 |
0.20 |
0.17 |
0.52 |
| Mn |
0.00 |
0.00 |
0.00 |
0.00 |
| Mg |
3.42 |
1.75 |
0.85 |
5.85 |
| Ca |
0.00 |
0.01 |
0.00 |
0.09 |
| Na |
0.00 |
0.00 |
0.00 |
0.12 |
| K |
0.00 |
0.00 |
0.00 |
0.00 |
|
|
|
|
|
| Total |
14.18 |
4.00 |
3.01 |
15.06 |
|
|
|
|
|
| XMg |
0.92 |
0.90 |
0.83 |
0.89 |
| |
Mg-amphibole (gedrite) |
Ca-amphibole (pargasite) |
Ca-amphibole (tschermakite?) |
Kornerupine |
Tourmaline |
| |
|
|
|
|
|
| |
e |
Range |
f |
Range |
g |
h |
Range |
i |
| SiO2 |
48.87 |
43.50–52.3 |
45.11 |
42.61–48.92 |
46.19 |
30.60 |
30.22–31.08 |
36.08 |
| TiO2 |
0.33 |
0.23–0.59 |
0.95 |
0.76–1.31 |
0.58 |
0.06 |
0.05–0.09 |
1.00 |
| Al2O3 |
14.58 |
10.35–21.39 |
13.69 |
10.21–16.01 |
11.98 |
41.53 |
40.43–42.78 |
30.42 |
| Cr2O3 |
0.01 |
0.00–0.03 |
– |
– |
0.00 |
0.04 |
0.03–0.05 |
0.01 |
| FeO |
4.80 |
4.04–5.18 |
3.25 |
3.04–3.44 |
4.80 |
2.97 |
2.61–3.17 |
2.41 |
| MnO |
0.03 |
0.00–0.08 |
0.01 |
0.00–0.04 |
0.05 |
0.00 |
0.00–0.00 |
0.02 |
| MgO |
26.69 |
24.95–27.65 |
18.81 |
17.90–19.96 |
18.44 |
19.81 |
19.67–20.04 |
11.17 |
| CaO |
0.84 |
0.51–1.08 |
12.22 |
11.71–12.65 |
12.62 |
0.07 |
0.02–0.13 |
3.08 |
| Na2O |
1.49 |
0.57–3.06 |
2.31 |
1.35–2.99 |
1.55 |
0.06 |
0.05–0.07 |
1.13 |
| K2O |
0.00 |
0.00–0.01 |
0.23 |
0.19–0.26 |
0.23 |
0.00 |
0.00–0.01 |
0.02 |
| NiO |
0.02 |
0.00–0.05 |
– |
– |
0.00 |
0.08 |
0.03–0.13 |
0.00 |
| P2O5 |
0.01 |
0.00–0.03 |
– |
– |
0.02 |
– |
– |
0.00 |
| B2O3 |
– |
– |
– |
– |
– |
3.00 |
2.78–3.28 |
– |
|
|
|
|
|
|
|
|
|
| Total |
97.67 |
| 96.58
|
| 96.45
|
98.22 |
|
85.35 |
| Representative formulae |
|
| Cations |
Basis of 23(O) |
Basis of 23(O) |
Basis of 23(O) |
Basis of 21.5(O) |
Basis of 24.5(O) |
| Si |
6.60 |
6.36 |
6.53 |
3.77 |
5.87 |
| Ti |
0.03 |
0.10 |
0.06 |
0.01 |
0.12 |
| Al |
2.32 |
2.28 |
2.00 |
6.02 |
5.84 |
| Cr |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
| Fe3+ |
0.05 |
0.30 |
0.46 |
0.00 |
0.00 |
| Fe2+ |
0.50 |
0.09 |
0.11 |
0.31 |
0.33 |
| Mn |
0.00 |
0.00 |
0.01 |
0.00 |
0.00 |
| Mg |
5.36 |
3.95 |
3.88 |
3.63 |
2.71 |
| Ca |
0.12 |
1.85 |
1.91 |
0.01 |
0.54 |
| Na |
0.39 |
0.63 |
0.43 |
0.01 |
0.36 |
| K |
0.00 |
0.04 |
0.04 |
0.00 |
0.05 |
| B |
– |
– |
– |
0.64 |
– |
|
|
|
|
|
|
| Total |
15.38 |
15.59 |
15.42 |
14.40* |
15.77 |
|
|
|
|
|
|
| XMg |
0.91 |
0.91 |
0.87 |
0.92 |
0.89 |
| |
Rutile |
Vermiculite |
Smectite |
| |
|
|
|
| |
j |
Range |
k |
Range |
1 |
Range |
| SiO2 |
0.01 |
0.00–0.03 |
35.81 |
32.74–39.74 |
47.84 |
45.73–50.57 |
| TiO2 |
99.69 |
98.23–100.27 |
0.98 |
0.49–1.64 |
0.05 |
0.01–0.07 |
| Al2O3 |
0.06 |
0.02–0.09 |
16.51 |
14.15–22.08 |
8.49 |
7.63–9.62 |
| Cr2O3 |
0.05 |
0.01–0.09 |
0.01 |
0.00–0.03 |
0.03 |
0.00–0.06 |
| FeO |
0.41 |
0.37–0.47 |
2.55 |
1.63–6.06 |
6.45 |
4.65–7.91 |
| MnO |
0.00 |
0.00–0.01 |
0.01 |
0.00–0.09 |
0.01 |
0.00–0.02 |
| MgO |
0.02 |
0.00–0.04 |
24.12 |
21.72–30.88 |
14.70 |
11.62–16.41 |
| CaO |
0.03 |
0.00–0.08 |
1.12 |
0.26–2.89 |
1.02 |
0.53–1.49 |
| Na2O |
0.00 |
0.00–0.02 |
0.24 |
0.00–0.57 |
0.02 |
0.00–0.04 |
| K2O |
0.00 |
0.00–0.00 |
0.42 |
0.02–1.46 |
0.10 |
0.03–0.22 |
| NiO |
0.00 |
0.00–0.00 |
0.01 |
0.00–0.10 |
0.04 |
0.00–0.09 |
| P2O5 |
0.01 |
0.00–0.02 |
0.01 |
0.00–0.04 |
0.03 |
0.00–0.08 |
|
|
|
|
|
|
|
| Total |
100.28 |
| 81.79 |
|
78.78 |
|
