Compressibility, Dissipation, and Heat Sources Effect on Temperature and Heat Flow Distribution in the Earth’s Mantle

Abstract—In accordance with the energy conservation law, at convection, the total heat released through adiabatic flow and the dissipative heat mutually exactly compensate as these are the internal processes. However, the allowance for these processes, compared to the Boussinesq approximation for incompressible mantle, changes the temperature gradient, with the temperature itself changing by up to 500 K, and almost halves the mantle heat flow. In this work, the effects of dissipation and adiabatic compressibility of the material on the mantle temperature and heat flow distributions are analyzed and the role of internal heat sources is examined. The effects of dissipation and adiabatic compression can be interpreted as the effective heat sources nonuniformly distributed in space. Negative homogeneous heat sources always increase the heat flow from the core. However, in reality, adiabatic compressibility integrally equivalent to a negative heat source reduces the heat flow from the core just as dissipation.