Crust evolution scenarios. Differentiation models produce an undifferentiated crust that could remain stable following an extreme scenario 2. Another extreme scenario (endmembers 1.2 and 3.2) would produce a body with free water completely differentiated from rock if the crust were assumed to have a low viscosity. An intermediate case is represented by the mixing of crust with the water mantle resulting in a mixed H₂ O-rock mantle (endmembers 1.1 and 3.1) that could experience some weak differentiation processes at present or where differentiation could have been interrupted due to cooling in a geologically recent past.