EVOLUTION OF THE EARTH'S INTERNAL STRUCTURE IN THE CONVECTIVE COOLING STAGE

Abstract

Geophysical and geological data indicate that in the case of the earth, the initial stage of stratification concluded with the formation of a heavy core about 2.9 to 3.0 million years ago and that the planet is currently in the convective cooling stage. A comparison of geological data suggests that this stage is associated with strongly supercritical convection in the core and mantle. We evaluate the characteristic duration of this stage of evolution and the corresponding scale of changes in temperature and other characteristics in the interior of the earth. The model equations of state used in our calculations give only a general qualitative representation of the earth's evolution, but a rather reliable estimate of the order of magnitude of the changes in the main properties of the interior. The use of more detailed equations of state will produce only relatively small qualitative changes, while the overall qualitative picture of the earth's evolution will remain the same.