Evolution into the stagnant lid convection regime with a non-Newtonian water ice rheology

[ 1] We study and compare the evolution into the stagnant lid regime with a non-Newtonian water ice and a silicate rheology by solving the equations of thermal convection. Dislocation creep of water ice is characterized by a larger stress dependence ( n = 4) than silicates ( n = 3) and with this water ice rheology, the stagnant lid regime is attained at a temperature determined viscosity contrast greater than 10 10 and at an effective viscosity contrast of -10 5. We also determine a Nusselt-Rayleigh number scaling law for the n = 4 rheology.