FROM VOYAGER TO CASSINI: 30 YEARS OF EXPLORING TITAN'S GEOLOGY

Coincidentally, the formation of of the GSA's planetary division thirty years ago coincided with the first spacecraft exploration of Titan. Voyager 1 flew by Titan at close range on 1980 August 22. But while Voyager discovered exotic organic chemistry and atmospheric mysteries, Titan's ubiquitous haze prevented observations of the surface geology. The era of Titan geology took off in 2004 with the arrival of Voyager's successor, the Cassini Saturn orbiter and particularly the Huygens Titan atmospheric probe. Cassini-Huygens has revealed Titan to be a richly complex world, outmatching every planet but Earth with the diversity of its geologic processes. Titan's methane storms rain on the surface, eroding it into channels that flow and deposit sediment into lakes and seas at the poles. Near the equator, giant seas of longitudinal dunes stretch almost all the way around the globe, overprinting impact craters and flowing around topographic obstacles. Though it lacks plate tectonics, Titan's mountains form into modest kilometer-high linear ranges, exposing bedrock as they erode. Finally, new observations show the best evidence yet for unique water-ice-rich volcanism. Together these physical processes have created a sediment-dominated world strikingly similar to our own in a morphological sense, despite Titan's exotic chemistry and frigid temperatures.