Geology of Titan and Composition Constraints from Cassini data
Résumé
Titan has an active methane-based hydrologic cycle that has shaped a complex geologic land-scape, making its surface one of most geologically diverse in the solar system. Despite the different materials, temperatures, and gravity fields between Earth and Titan, both worlds share remarkably similar surface features that can be interpreted as products of the same geologic processes. We identified and mapped the major geologic units on Titan's surface using data from the Cassini spacecraft's RADAR (in Synthetic Aperture Radar, altimetry, and passive radiometry modes), Visual and Infrared Mapping Spectrometer (VIMS), and Imaging Science Subsystem (ISS). We placed Titan's terrain types in stratigraphic order, making it possible to constrain the relative importance and global distribution of various endogenic and exogenic processes. Using data from VIMS, we constrained the composition of the various terrains. The six major geologic units are plains, dunes, hummocky terrains, lakes, labyrinth terrains, and craters. Mapping the distribution of these units enables us to discern their latitudinal distribution, superposition relations, composition, and areal coverage, and the implications for Titan's geologic history. We find that Titan's surface is dominated by sedimentary/depositional processes with significant dependence on latitude.