抄録
The possible thermal history of the earth in the absence of convection is studied by comparing numerical calculations of the development of thermal state within several model earths with observed facts. The following conditions are adopted to study thermal evolution: (1) excitonic heat transfer in the earth's mantle, (2) absorption of melting heat in melting process, (3) influence for initial temperature due to formation of an iron core, and (4) longenduring process of differentiation of the upper parts of the mantle.
The total heat conductivity in limits from 400km. to the base of the mantle is of the same order as the core. Such a high heat transfer by conduction is equivalent to the amount of heat transported by mantle convection current having the speed of about 0.1cm/year for the present time, which exerts a considerable influence on the computed temperature within mantle. The modern features of temperature-depth curves are very similar in cited models in which energy is transmitted by exciton, photon, and phonon. The current temperature on the possible earth models approaches but not exceeds the melting temperature of forsterite at depths between 200 and 400km.
