Abstract
Chemical structure of a simplified model of the planet of which the components are Fe-Si-O is discussed. Chemical equilibrium and hydrostatic equilibrium are assumed and emphasis is placed on gravitational separation due to density differences and chemical interaction among components, which control the equilibrium arrangement of stable phases.It is concluded that the present gravitational field of the earth is too strong for reasonable arrangement of the components.
Models with probable gravitational field are discussed and the following conclusions are obtained; (a) in 2, 000°K isothermal model, Fe2SiO4 content shows a maximum at a certain depth and SiO2 and FeO which are at shallower and deeper depths respectively will disappear soon; (b) in 2, 000°K (surface)→6, 000°K (center) model, the radius of the Fecore is one-half of the earth's radius. The mantle is composed of Fe2SiO4, SiO2 and isolated O.
