Evaluation of thermochemical data on Fe-Mg olivine, orthopyroxene, spinel and Ca-Fe-Mg-Al garnet
Thermochemical data on Fe-Mg olivine, orthopyroxene, spinel and Ca-Fe-Mg garnet have been tested and reevaluated in reproducing experimental equilibrium data. All data (except of spinel) adjusted in this process lie within the error limits of original calorimetric experiments. For spinel, an enthalpy of -2307.2 kJmol and an entropy of 81.5 Jmol-K has been recommended. Recommended interaction parameters for the spinel-hercynite and forsterite-fayalite solutions are as follows: Spinel: W/sub (spinel-hercynite)/= 9124.0 Jmol. W/sub (hercynite-spinel)/ = 0.0 Jmol. Olivine: W = 4500.0 Jmol for 1 cation. Excess entropies (on 1 cation basis) necessary to reproduce phase equilibria for the pyrope-almandine and almandine-grossular solutions are as follows: Mg-Fe garnet: Wsub(pyrope-almandine) = 11.760 - 0.0016T Jmol-K. Wsub(almandine-pyrope) = -10.146 + 0.0037T Jmol-K. Fe-Ca garnet: W/sup s/ = -16.07 + 0.0126T Jmol-K.
- Research Organization:
- City Univ. of New York, NY (USA)
- OSTI ID:
- 5064746
- Journal Information:
- Geochim. Cosmochim. Acta; (United States), Journal Name: Geochim. Cosmochim. Acta; (United States) Vol. 51:9; ISSN GCACA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580400* -- Geochemistry-- (-1989)
ACTIVATION ENERGY
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CHEMICAL ACTIVATION
DATA
ENERGY
ENTHALPY
ENTROPY
EQUILIBRIUM
EXPERIMENTAL DATA
GARNETS
INFORMATION
IRON COMPOUNDS
IRON SILICATES
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MAGNESIUM SILICATES
MINERALS
NUMERICAL DATA
OLIVINE
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PARAMETRIC ANALYSIS
PHASE STUDIES
PHYSICAL PROPERTIES
PYROXENES
RELIABILITY
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SPINELS
THERMOCHEMICAL PROCESSES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS