Poludnista Dorsa, Venus: History and context of a deformation belt

[1] Rolling lowlands comprise 80% of Venus’s surface, and thus developing a geological understating of resurfacing and tectonism is critical for our understanding of Venus’ evolution. In this paper, global, regional, and local approaches to interpreting Magellan synthetic aperture radar and altimetry radar data are used to constrain modes of lowland evolution, convection processes, and lithospheric structure. Detailed geologic mapping is combined with altimetry data test models of deformation belt evolution in Venus’s lowlands. Poludnista Dorsa, a complex 2000-km-long deformation belt, is highly segmented and broadly time transgressive. Long-wavelength deformation is spatially independent of local short-wavelength deformation within the deformation belt and temporally predates regional deformation marked by wrinkle ridges. A mechanically layered lithosphere of regional extent is not required by the local geologic history; local lithospheric thinning or progressive regional thickening of the mechanical layer better explains the observed sequence of events.