Effects of pressure on the melting and polymorphism of enstatite, MgSiO3
| Autor: | Brian T. C. Davis, J. L. England, F. R. Boyd |
|---|---|
| Rok vydání: | 1964 |
| Předmět: |
Atmospheric Science
Incongruent melting Triple point Soil Science Thermodynamics Mineralogy Aquatic Science engineering.material Oceanography Melting curve analysis Pressure range Geochemistry and Petrology Earth and Planetary Sciences (miscellaneous) Earth-Surface Processes Water Science and Technology Ecology Atmospheric pressure Paleontology Forestry Geophysics Polymorphism (materials science) Space and Planetary Science High pressure Enstatite engineering Geology |
| Zdroj: | Journal of Geophysical Research. 69:2101-2109 |
| ISSN: | 0148-0227 |
| DOI: | 10.1029/jz069i010p02101 |
| Popis: | The melting curve of enstatite, MgSiO3, has been determined in the pressure range 5 to 46 kb. The data can be fitted by a smooth curve originating at the incongruent melting point at atmospheric pressure (1557°C). Simon constants for this curve are A = 28.5 and c = 5.01. The initial slope is 12.8 deg/kb, but it flattens to about 6 deg/kb in the range 40 to 50 kb. The melting curve is intersected by the polymorphic transition protoenstatite ⇄ rhombic enstatite, with rhombic enstatite as the high-pressure phase. The transition curve is approximately T = 985°C + 84P (kb), with the triple point protoenstatite-rhombic enstatite-liquid at 1650°C and 8.0 kb. Enstatite melts congruently at high pressure. Experimental data show that the pressure at which the melting changes from incongruent to congruent must be less than 5.4 kb. Thermodynamic calculations indicate that it is probably about 2.3 kb. These data suggest that rocks which show textural evidence of an olivine-liquid reaction relation have developed this relation at relatively shallow depth, probably less than about 9 km. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text