"Modeling the deformation of landforms on Mars by creep of ground ice"
A suite of mid- to high-latitude surface features on Mars has been attributed to viscous flow phenomena associated with near-surface deposits of ground ice (Squyres et al. 1992), an interpretation that is consistent with recent Mars Odyssey GRS observations indicating a high water content close to the Martian surface (Boynton et al. 2002). Squyres (1989) identified two classes of creep-related landforms: (1) softened terrain resulting from in situ viscous deformation, and (2) debris aprons produced by mass wasting along escarpments. We are using finite-element analysis, incorporating recent measurements of the rheological parameters for water-ice/particulate mixtures, to simulate the deformation of impact craters and debris aprons by viscous creep of ice-rich permafrost. By comparing our model results to the structural and topographic characteristics of landforms that we have documented using MGS MOC and MOLA data, we can constrain the conditions necessary for such deformation to occur. Our simulations demonstrate that even under present Martian conditions flow can occur quite rapidly, ~10,000 years. However, if the mobility of the ice is restricted by a surface layer that resists deformation, or the high volume fractions of ice inferred from GRS data to be present near the surface do not persist to significant depths, deformation timescales could be significantly longer.
Useful Link: Modeling deformation of impact craters on Mars by viscous creep of ground ice