1. Magmatic Phases - I

2. Magmatic Phases - II

3. Conceptual Models of Silicate Melts
From Carmichael et al. 1974

4. Specific Volume of Pure Water
Geothermal
Gradient
Critical Point
From Burnham et al., 1969

5. Specific Volume of Water vs. Pressure
specific volume = 1 / r
0.1 g/cm3
rmagma = 2.2 g/cm3

6. Magmatic Volatile Reservoirs
PH2O < Pf
Px = Py = Pz
Isostatic = Lithostatic pressure

7. Water Solubility vs. Pressure
“Cold-Seal” bomb
Pressure medium
Platinum capsule:
contains melt +
dissolved volatiles
To pump to increase
pressure
From Moore et al., 1998

8. Depolymerization of Silicate Melts

9. Speciation of Water in Silicate Melts
H2O + O2- = 2OH-
in melt in melt
From Silver et al., 1990

10. CO2 Solubility in Silicate Melts
aSiO2

11. Pressure Effects on Volatile-rich Systems

12. Volatiles and Eruptions

14. Explosive Eruptions