6:15 PM - 7:30 PM
[SIT35-P07] Numerical experiments on mantle convection of super-Earths with variable thermal conductivity and adiabatic compression
Keywords:suoer-Earths, mantle convection, adiabatic compression, thermal expansivity, thermal conductivity, viscosity
Our numerical experiments showed the change in convecting flow patterns depending on the temperature-dependence in viscosity, regardless of the depth-dependence in thermal conductivity. When a viscosity is sufficiently dependent on temperature, horizontal flow becomes dominant in the mantle, with a very weak activity of hot plumes from the base of the mantle. This flow pattern is quite similar to the "stratosphere" in the field of meteorology. In addition, we found that the occurrence of "stratosphere" is enhanced for a strong depth-dependent thermal conductivity. One reason for this is that high conductivity at depth significantly reduces the difference in temperature between the basal thermal boundary layer and isothermal core. Our study therefore suggests that the depth-dependent thermal conductivity is one of the most important agents which control the mantle dynamics of super-Earths.