ISSN:
1432-2021
Schlagwort(e):
Key words Element partitioning
;
High pressure phase relation
;
Mixing property
;
Spinel
;
Magnesiowüstite
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
,
Geologie und Paläontologie
,
Physik
Notizen:
Abstract Mg-Fe partitioning experiments between (Mg,Fe)2SiO4 spinel and (Mg,Fe)O magnesiowüstite were carried out at pressures of 17–21.3 GPa at temperatures of 1400 and 1600 °C, using a multi-anvil apparatus, in order to determine interaction parameters of spinel and magnesiowüstite solid solutions and also to constrain the equilibrium boundaries of the postspinel transition in the Fe-rich side in the system Mg2SiO4-Fe2SiO4. The obtained values of the interaction parameters were 3.4 ± 1.5 and 13.9 ± 1.4 kJ mol−1, respectively, for spinel and magnesiowüstite solid solutions at 19 GPa and 1600 °C. The partitioning data in the system Mg2SiO4-Fe2SiO4 at 1400 and 1600 °C showed that the transition boundary between spinel and the mixture of magnesiowüstite and stishovite has a negative dP/dT slope. Using the above interaction parameters and available thermodynamic data of the Mg2SiO4 and Fe2SiO4 end members, the transition boundaries of spinel to the mixture of magnesiowüstite and stishovite were calculated. Within the uncertainties of the data used, the calculated boundaries are in good agreement with the boundaries at 1400 and 1600 °C experimentally determined in this study. The dissociation boundary of Fe2SiO4 spinel to wüstite and stishovite, calculated from the thermodynamic data, has a negative slope of −1.5 ± 0.6 MPa K−1.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/s002690050260
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