Resurfacing of Titan by ammonia-water cryomagma

Giuseppe Mitri, Adam P. Showman, Jonathan I. Lunine, Rosaly M.C. Lopes

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

Abstract

The Cassini Titan Radar Mapper observed on Titan several large features interpreted as cryovolcanic during the October 26, 2004 pass at high northern latitudes [Lopes, R.M.C., and 43 colleagues, 2007. Icarus 186, 395-412]. To date, models of ammonia-water resurfacing have not been tied to specific events or evolutionary stages of Titan. We propose a model of cryovolcanism that involves cracking at the base of the ice shell and formation of ammonia-water pockets in the ice. As these ammonia-water pockets undergo partial freezing in the cold ice shell, the ammonia concentration in the pockets increases, decreasing the negative buoyancy of the ammonia-water mixture. If the ice shell is contaminated by silicates delivered in impacts, the liquid-solid density difference would be even less. While the liquid cannot easily become buoyant relative to the surrounding ice, these concentrated ammonia-water pockets are sufficiently close to the neutral buoyancy point that large-scale tectonic stress patterns (tides, non-synchronous rotation, satellite volume changes, solid state convection, or subsurface pressure gradients associated with topography) would enable the ammonia to erupt effusively onto the surface. Rather than suggesting steady-state volcanism over the history of the Solar System, we favor a scenario where the cryovolcanic features could have been associated with episodic (potentially late) geological activity.

Original languageEnglish (US)
Pages (from-to)216-224
Number of pages9
JournalIcarus
Volume196
Issue number1
DOIs
StatePublished - Jul 1 2008

Keywords

  • Geophysics
  • Ices
  • Interiors
  • Satellites
  • Saturn
  • Titan
  • Volcanism
  • surfaces

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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