Formation and Evolution of Planetary Stagnant Lids and Crusts

Earth is the only known planet with plate tectonics, which involves a mobile upper thermal boundary layer. Other terrestrial planets show a one-plate immobile lithosphere, or stagnant lid, that insulates and isolates their interior. Here, we first review the different types of lids that can develop on rocky and icy bodies. As they formed by accretion, involving high-energy impacts, terrestrial planets likely started hot and molten. We examine the process of lid initiation from a magma ocean stage and develop the equations for lid growth. We survey how lateral perturbations in lid and crust thickness can be amplified during their growth and finally discuss the possible processes at the origin of lid rupture and plate generation.