On Mars, the interiors of the basins have been modified by erosion, sedimentation, etc. D. Craters are used to date planetary surfaces. The general rule is that the more heavily cratered a surface is the older it is. Use is complicated by lack of knowledge of the number and size of impactors as a function of distance and time. Volcanism A. Planets with thin lithospheres and high internal temperatures tend to have more active volcanism.
All terrestrial planets show evidence of volcanism, though manifestation is different.
C. Types depend on viscosity, temperature, and volatile content of lava 1. Volcanic plains 2. Shield volcanoes 3. Tectonics A. Associated often with mantle convection and resulting stresses B. More important as lithosphere gets thinner C. On earth gives rise to plate tectonics and continental drift. Not clear whether either Mars or Venus ever had tectonics like the earth.