Message #262690

[Paradox]

The crust is pretty thick on Venus. And the lithosphere (the upper portion of the mantle + the crust) is thick too. And pretty uniform. Based on the distribution of topography (unimodal). The Earth's distribution of topography (bimodal) indicates plate tectonic processes. One of the main reasons, actually, for the lack of plate tectonics is believed to be the comparative difference in water content of the interior. Water has a major influence on rock strength/melt temperature. Venus has less water than Earth (is what accretion models indicate), so it has a strong, thick lithosphere.