Geology Reference
In-Depth Information
Fig. 12.10 a The join
kalsilite-leucite at 1 atm and
2.0 GPa for volatile-absent
and CO
2
- saturated
conditions. The results at
1 atm are from Schairer and
Bowen (1955). The melting
temperature of leucite at
2.0 GPa for volatile-absent
conditions is from Lindsley
(1966). Phase abbreviations
are same as Fig.
12.6
(after
Wendlandt and Eggler 1980).
or the joins
KAlSiO
4
(a)
1800
1700
L
Ks+L
Lc+L
1 atm
1600
Ks+Lc
L
Lc
+L
Ks+L
,
,
1500
Ks+Lc
L+V
1400
Ks+L
+V
,
,
2
Ks+Lc+V
Lc+L+V
Subsolidus
Ks+L
1300
Ks+L+V
Lc+L
Lc+L+V
L - V
1200
KAlSiO
4
20
40
60
80
KAlSi
2
O
6
Mg
2
SiO
4
SiO
2
-
-
Weight Percent
and)
KAlSiO
4
CO
2
.
b The join leucite-forsterite at
1 atm and 2.0 GPa for
volatile-absent and CO
2
-
saturated conditions. The
results at 1 atm are from
Schairer and Bowen (1954).
The melting temperature of
leucite at 2.0 GPa for volatile-
absent conditions is from
Lindsley (1966). Phase
abbreviations are same as
Fig.
12.4
(after Wendlandt
and Eggler 1980)
MgO
SiO
2
-
-
-
(b)
1800
Subsolidus
Fo+L
1700
Fo+L+V
Lc+L
+
L - V
L
1600
Fo+L
Lc+L
1 atm
1500
Lc+Fo
L
Fo+L
+
,
,
Lc
1400
Lc+Fo
L+V
Fo+L+V
,
,
2
1300
Lc+L+V
Lc+ +V
Fo
1200
KAlSi
2
O
6
20
40
60
80
Mg
2
SiO
4
Weight Percent
kalsilite-leucite join,
there is a systematic shift
for
the three-phase point
(leucite + kalsilite +
fluid) compared to one atmosphere three-phase point estab-
lished by Schairer (1954). Note that since the composition of the
fluid cannot be
plotted in the leucite-kalsilite join, the point, where leucite, kalsilite and
fluid-
coexist in equilibrium, is not a eutectic. In case of the leucite
forsterite join the
-
three-phase point shifts toward leucite under both
fluid-present
conditions, compared to the three phase point established under one atmospheric
pressure by Schairer (1954). The effect of shift of the three-phase point toward
leucite in case of both the joins is more in case of CO
2
-saturated runs than the
fluid-absent and
fluid-
absent runs.
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