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Fo
En
(a)
(g)
Fo
En
Fo
En
Fo
En En
IP<I
2
<
Fo
I <P<I
14
4
P<I
5
P<I
6
En
Fo
Lc
En
16
Ks
Sa
Sa
Ks
Lc
Sa
SiO
2
Ks
Lc
Sa
SiO
2
(b)
Fo
En
(h)
En
Fo
En
Fo
Fo
Fo
En
Fo
I
16
<
P
I
<P<S
18
I
5
<P<S
3
I<P<S
9
6
En
14
En
Fo
Lc
Ks
Sa
Sa
Ks
Sa
SiO
2
Ks
Lc
Sa
SiO
2
Fo
(i)
En
(c)
En
Fo
En
Mag
En
Fo Fo
Fo
Lc
En
En
Fo
S<P<S
19
18
SP<S
3
<
S
9
<P<S
10
En
4
Sa
Ks
Sa
Ks
Sa
SiO
2
Ks
Lc
Sa
SiO
2
Fo
En
En
Mag
(j)
(d)
Fo
En
Mag
En
Fo
Fo Fo
Fo
Lc
En
En
En
S<P<S
20
19
SP<S
4
<
S
<P<S
11
5
10
Ks
Sa
Sa
Ks
Sa
SiO
2
Ks
Lc
Sa
SiO
2
(k)
Fo
En
Mag
(e)
En
Fo
En
En
Mag
Fo
Fo
En
En
Fo
Ks
SP<S
5
<
S <P<S
12
11
S<P<
8
20
6
Fo
En
Sa
Lc
Sa
Ks
Ks
Lc
Sa
SiO
2
Ks
Sa
SiO
2
Fo
(l)
En
Mag
(f)
En
En
Fo
En
Mag
Fo
Fo
En
En
I<P
8
IP<S
2
<
S
<P<I
4
Ks
Fo
6
12
En
Sa
Sa
Ks
Ks
Sa
SiO
2
Ks
Lc
Sa
SiO
2
Fig. 12.9 Schematic liquidus projections for the joins KAlSiO
4
Mg
2
SiO
4
SiO
2
and KAlSiO
4
-
-
-
MgO
CO
2
. Magnesia contents of liquids are exaggerated, except for carbonate-rich liquids,
for which the magnesia contents are probably too low. Pressures to the left of each figure refer to
the volatile-absent join (Figs.
12.5
and
12.6
): pressures to the right of each figure refer to the CO
2
-
bearing join (Figs.
12.7
and
12.8
) (after Wendlandt and Eggler 1980)
SiO
2
-
-
K
2
O and Al
2
O
3
and low MgO and are similar to such rocks as leucitite, leucite-
bearing nephelinite and leucite tephrite. The other groups are characterised low
K
2
O and Al
2
O
3
and high MgO and are similar to ankaratrites, basanites, and
nephelinites.
Wendlandt and Eggler also studied the joins, kalsilite-leucite (Fig.
12.10
a) and
leucite
forsterite (Fig.
12.10
b) for
fluid- absent and CO
2
-saturated conditions at
-
2.0 GPa and different
temperatures. Figure
12.10
a shows that
in case of the
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