Thermodynamic Properties Across Seismic Discontinuities Show Strong Variations due to Compositional Effects
Abstract
Thermodynamic properties of solid solution phases change with pressure, temperature and composition. In regions involving several of such phases, the change of pressure and temperature leads to a change in their composition. For the MgO-FeO-SiO2 system, we demonstrate that the values of specific properties may change up to a 100% due to compositional effects in the regions associated with the 410 km and 660 km seismic discontinuities. However such changes are negligible in the lower mantle. The Figures show two examples of large compositional effects on heat capacity and bulk modulus in the transition zone for a pyrolitic overall composition (Mg0.9}Fe{0.1)_2SiO_4 without pyroxene
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2003
- Bibcode:
- 2003AGUFM.T11C0404J
- Keywords:
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- 3939 Physical thermodynamics;
- 5102 Acoustic properties;
- 5134 Thermal properties;
- 8124 Earth's interior: composition and state (old 8105);
- 8147 Planetary interiors (5430;
- 5724)