Journal of Physics of the Earth

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Evolution of the atmosphere and the hydrosphere is discussed, based upon a hypothesis that they have grown by a gradual outgassing of H₂O, CO₂, HCl, N₂, CO and H₂S from the interior of the earth. A liquid state of H₂O at the terrestrial surface plays an important role and the partial pressure of CO₂ in the atmophere does not change appreciably owing to its high solubility into the sea water. Equilibrium composition of the outgassing materials is calculated for T=300-2, 000°K, P=1-10⁴atm., and various values of H/O. The method of minimizing the total free energy is employed (§2). Equilibrium composition of the sea water is calculated as a function of Cl- concentration and POO₂. Concentrations of Na+, K+, Mg⁺² are assumed to be controlled by the exchange reactions between the sea water and the Al-silicates. Based upon the results thus obtained, a chemical model of the evolution of the atmosphere and the hydrosphere is presented where a quasi-static equilibrium state is supposed (§3).
For the next, physical aspects of the dynamic character of the model are discussed. Numerical experiments are carried out for the dynamic geochemical cycle in which the material supply from the mantle and the material transfer via atmosphere and the solid crust are considered. A nearly steady state of the composition of the sea water (Cl, S, Na, K, Ca, Mg) is obtained (§4). A few numerical experiments on the geochemical cycle of carbon including biological bodies are also carried out (§5).

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The structure of the crust and upper mantle in Finland has been studied by utilizing results of surface wave phase and group velocity determinations and of explosion seismic refraction measurements. The dispersion curves for a set of theoretical models have been calculated by the Thomson-Haskell matrix method. The earth-stretching transformations of Anderson and Toksoz were used in the calculation of Love wave dispersion. The derived layer model has a crustal thickness of 42km and a major crustal discontinuity at the depth of 12km. The existence of a low-velocity layer in the upper mantle with the upper boundary of it at a depth lower than 150km could not be shown with the available data.

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