Geoscience Reference
In-Depth Information
Here, it is appropriate to discuss one or two important systems studied in the
early twentieth century. Perhaps, the first systematic and pioneering study of the
hydrothermal system began with the publication of the work on the ternary system
H
2
O
SiO
2
by Morey and Fenner
[44]
.
This work gives a more precise account of the pressure and temperature condi-
tions throughout the experiment. Besides, nutrient materials were prepared from
highly pure substances and consequently the composition of the charges used in
each experiment was precisely known. The paper carried great significance to
geological science as it demonstrated clearly the possibility of a complete solubility
between anhydrous silicate phases and water, which in turn assisted in framing a
mechanism for pegmatite crystallization in the presence of a volatile. Morey and
Fenner
[44]
studied this system from 200
Cto
a
K
2
SiO
3
a
1000
C
[42]
. The work comprises
the determination of the composition and properties of the various stable solid
phases which can coexist with solution and vapor within the above temperature
range, the composition of the solutions in equilibrium with the solid phases, the
change in composition of these solutions with temperature, and the approximate
determination of the corresponding three-phase pressures. Morey and Fenner used
the famous Morey autoclave in all their work on phase equilibria studies in differ-
ent systems. The isothermal polybaric saturation curves and the isobaric polyther-
mal saturation curve at 1 atm pressure of H
2
O vapor is shown in
Figure 2.5
.
The most significant aspect of this work is that a new trend can be observed
here with reference to the theoretical relations governing the equilibrium in binary
and ternary systems containing a volatile component, and a short discussion of the
proper application of the term solubility. Besides Morey and his group, another
group from the same laboratory led by Bowen was very active during that time.
The study of the PVT relations of water became popular during the late 1920s.
The works of van Nieuwenburg and Blumendahl
[45]
followed by Keenan and
.
Figure 2.5 The isothermal polybaric
saturation curves and the isobaric
polythermal saturation curve at
1 atm pressure of H
2
O vapor
[44]
.
K
2
SiO
2
K
2
SiO
3
.1/2 H
2
O
K
2
SiO
2
O
5
K
2
SiO
3
. H
2
O
600
520
K
2
Si
2
O
5
.H
2
O
380
420
360
285
500
480
208
420
KNSi
2
O
5
H
2
O
SiO
2
