Join CaAl/sub 2/Si/sub 2/O/sub 8/-H/sub 2/O (anorthite-water) at elevated pressures and temperatures

Journal Article · · Am. Mineral.; (United States)

OSTI ID:5299234

Goldsmith, J R

A portion of the join anorthite-water in the quaternary system CaO-Al/sub 2/O/sub 3/-SiO/sub 2/-H/sub 2/O has been reinvestigated in the range 550/sup 0/-990/sup 0/C, from 7 to 16 kbar. The reaction 4 anorthite + H/sub 2/O in equilibrium 2 zoisite + kyanite + quartz can be described by the equation P = -4590 + 20.4T, where P is in bars, T is in /sup 0/C. The reaction is terminated at an invariant point at 725/sup 0/C and 10.2 kbar, where melt first appears. The two reactions at higher temperatures and pressures are zoisite + kyanite + quartz + vapor in equilibrium liquid, and anorthite + vapor in equilibrium liquid, the latter delimiting the fields of anorthite + vapor and zoisite + kyanite + liquid + vapor. The incongruent melting of anorthite + water, beginning at 725/sup 0/C, is significantly lower than earlier reported, and is unusual in that the solid assemblage anorthite + vapor lies on the high-temperature side of the boundary.

• Research Organization: Univ. of Chicago, IL
• OSTI ID: 5299234
• Journal Information: Am. Mineral.; (United States), Vol. 66:11-12
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
ANORTHITE
MINERALOGY
ALUMINIUM SILICATES
CHEMICAL REACTION KINETICS
EQUILIBRIUM
EXPERIMENTAL DATA
QUARTZ
VERY HIGH TEMPERATURE
WATER
ALUMINIUM COMPOUNDS
CHALCOGENIDES
DATA
FELDSPARS
HYDROGEN COMPOUNDS
INFORMATION
KINETICS
MINERALS
NUMERICAL DATA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SILICON OXIDES
580400* - Geochemistry- (-1989)