| Popis: |
Intensive-variable phase diagrams are receiving more frequent use by petrologists. Phase relations for the system Fe-O-SiO 2 expressed in P-T-oxygen fugacity (intensive-variable) space provide a necessary building block for more complex but geologically important systems andalso illustrate several important principles in the construction of such diagrams. The important phase relations for this system can be derived by application of Schreinemakers9 rules to published experimental data obtained at 1 atm and a relatively few data obtained at high pressures. Two invariant assemblages, each of five condensed phases, occur in the system: fayalite-silica-ferrosilite-iron-liquid at 17.5 kb, 1280 degrees C, and 10 (super -10.85) atm oxygen fugacity; and fayalite-silica-ferrosilite-magnetite-liquid at 17 kb, 1205 degrees C, and 10 (super -7.25) atm oxygen fugacity. |
