• ices;
  • interiors;
  • Titan

[1] We have developed a thermal model of Titan's interior to study changes in volume during partial freezing or melting of a subsurface ocean due to heat flux variations from the interior. We find that the long-term cooling of Titan can cause global volume contraction ΔV/V ∼0.01. We then simulate two-dimensional contractional deformation of Titan's icy lithosphere, finding that contractional deformation can produce tectonic activity and fold formation. Folds could potentially achieve a topographic height of several kilometers for high local strain (∼0.16), and for high temperature gradients in the ice I shell (order of 10 K km−1), corresponding to an ancient high heat flux from the interior (order of 0.02–0.06 W m−2). Examination of Synthetic Aperture Radar (SAR) imagery obtained by Cassini Radar shows possible evidence of contractional tectonism in the equatorial regions of Titan, although the moderate resolution of the Cassini SAR imagery does not permit an unambiguous geological interpretation.