Temperature distribution in the Earth

The thermal regime of the Earth depends significantly on the conductivities of the Earth's material and on geodynamic processes in the Earth's interio r. Since the mantle is involved in convective motion, the average temperatu re distribution in the mantle should be close to the adiabatic law. The eff ectively fluid state of the outer core is evidence that its temperature dis tribution is adiabatic or lies below the adiabatic distribution if the core is appreciably heated from its surface. This paper considers a model accor ding to which core material is supplied from the lowermost mantle by a mech anism of pressure diffusion differentiation of the mantle material, separat ing eutectic melts of iron and its oxide from mantle silicates. Within the framework of this model, temperatures of the lower mantle at depths greater than 2000 km and of the outer corf: should exceed the melting temperatures of such eutectic compositions at pertinent pressures, and conversely, the temperature of the inner core should be lower than the iron melting tempera ture. Based on data of experiments ion high-pressure melting of iron and it s oxygen and sulfur compounds [Boehler, 1993, 1996], the probable temperatu re distribution in the mantle and core is calculated. According to the mode l results, the temperature reaches 3130 K at the base of the mantle and ris es to 5610 K at. the inner-outer core boundary and to 6140 K at the Earth's center.