title: Reorientation and faulting of Pluto due to volatile loading within Sputnik Planitia.
abstract: Pluto is an astoundingly diverse, geologically dynamic world. The dominant feature is Sputnik Planitia-a tear-drop-shaped topographic depression approximately 1,000 kilometres in diameter possibly representing an ancient impact basin. The interior of Sputnik Planitia is characterized by a smooth, craterless plain three to four kilometres beneath the surrounding rugged uplands, and represents the surface of a massive unit of actively convecting volatile ices (N2, CH4and CO) several kilometres thick. This large feature is very near the Pluto-Charon tidal axis. Here we report that the location of Sputnik Planitia is the natural consequence of the sequestration of volatile ices within the basin and the resulting reorientation (true polar wander) of Pluto. Loading of volatile ices within a basin the size of Sputnik Planitia can substantially alter Pluto's inertia tensor, resulting in a reorientation of the dwarf planet of around 60 degrees with respect to the rotational and tidal axes. The combination of this reorientation, loading and global expansion due to the freezing of a possible subsurface ocean generates stresses within the planet's lithosphere, resulting in a global network of extensional faults that closely replicate the observed fault networks on Pluto. Sputnik Planitia probably formed northwest of its present location, and was loaded with volatiles over million-year timescales as a result of volatile transport cycles on Pluto. Pluto's past, present and future orientation is controlled by feedbacks between volatile sublimation and condensation, changing insolation conditions and Pluto's interior structure.
authors.affiliation: Lunar and Planetary Laboratory, Department of Planetary Science, University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: James T
authors.initials: JT
authors.lastname: Keane
authors.affiliation: Lunar and Planetary Laboratory, Department of Planetary Science, University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: Isamu
authors.initials: I
authors.lastname: Matsuyama
authors.affiliation: Creative Research Institution, Hokkaido University, Sapporo, Japan.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Kamata
authors.affiliation: Purdue University, Department of Earth, Atmospheric, and Planetary Sciences, West Lafayette, Indiana 47907, USA.|Planetary Science Institute, Tucson, Arizona 85719, USA.
authors.forename: Jordan K
authors.initials: JK
authors.lastname: Steckloff