Global contraction/expansion and polar lithospheric thinning on Titan from patterns of tectonism

We investigate the underlying physical processes that govern the formation and evolution of Titan's tectonic features. This is done by mapping mountain chains and hills using Cassini RADAR data obtained during Titan flybys T3 to T69. Our mapping of mountain chains and hills reveals a global pattern: east-west orientations within 30 degrees of the equator and north-south between 60 degrees latitude and the poles. This result makes Titan one of the few solar system bodies where global processes, rather than regional processes, dominate tectonism. After comparison with five global stress models showing theoretical mountain chain orientations, we suggest that either global contraction coupled with spin-up or global expansion coupled with despinning could explain our observations if coupled with a lithosphere thinner in Titan's polar regions.