Gravity‐driven deformation of the crust on Venus

Intense horizontal deformation features are observed on the surface of Venus despite the apparent absence of terrestrial‐style plate tectonics. High surface temperature, low erosion rate, and regions of elevated terrain suggest that gravity spreading may be responsible for some of these features. Gravity spreading on the Earth is known to cause extensive deformation in certain thin‐skinned tectonic regions, where the uppermost layers become detached along a decollement. While the high pore pressures and soft sedimentary rocks frequently observed along decollements on the Earth are not plausible for Venus, temperature induced regions of ductile deformation may exist. Simple viscous models of gravity spreading above a ductile region of the crust are developed to examine the effects of rheology, thermal gradient, surface slope and crustal thickness on deformation. For a reasonable range of parameters, the models show that surface‐slope‐driven ductile deformation at relatively shallow depths in the crust is possible and may be capable of detaching the uppermost rigid portion of the crust, resulting in horizontal translation.