image: A 1,100-km-wide, false-color radar view of Lavinia Planitia, one of the lowland regions on Venus where the lithosphere has fragmented into blocks (purple) delineated by belts of tectonic structures (yellow). view more
Credit: Image credit: Paul K. Byrne and Sean C. Solomon.
A study finds features on Venus that suggest limited yet global crustal deformation driven by a convecting planetary interior. In contrast to the system of mobile tectonic plates on Earth, Venus has been assumed to have a globally continuous outer shell, or lithosphere. However, substantial surface deformation is evident on the planet, suggesting a convecting interior. Sean Solomon, Paul K. Byrne, and colleagues mapped a set of crustal blocks on Venus termed "campi," which are distributed globally in the planet's lowlands. The blocks, the largest of which is approximately the size of Alaska, show little deformation in their interiors but are bounded by belts of deformational features and appear to have moved laterally relative to one another. The campi are analogous to some continental crustal blocks on Earth, and their motions are akin to those of jostling pack ice. Modeling of viscous flow in the planet's interior revealed that stresses in the crust are consistent with the brittle failure of surface rocks observed in the areas where campi are present. The results support the hypothesis that convection in the planet's interior is likely responsible for the formation and relative motion of campi. According to the authors, the limited yet global mobility of the Venusian crust offers parallels to Earth's crust during the Archean Eon, when planetary heat flux was high and the lithosphere was likely thinner than at present.
###
Article #20-25919: "A globally fragmented and mobile lithosphere on Venus," by Paul K. Byrne et al.
MEDIA CONTACTS: Paul K. Byrne, North Carolina State University, Raleigh, NC; email: <paul.byrne@ncsu.edu>; Sean C. Solomon, Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY; tel: 202-550-1018; email: <solomon@ldeo.columbia.edu>
Journal
Proceedings of the National Academy of Sciences