P13B-2133
Geomorphology of Titan's polar terrains: Using the landscape’s topographic form to constrain surface processes
Monday, 14 December 2015
Poster Hall (Moscone South)
Samuel P Birch1, Alexander G Hayes Jr2, William E Dietrich1, Alan D Howard3, Michael J Malaska4, Jeffrey M Moore5, Marco Mastrogiuseppe6, Oliver L White7, Jason Daniel Hofgartner8, Jason M Soderblom9, Jason W Barnes10, Charlie Bristow11, Randolph L Kirk12, Elizabeth P Turtle13, Charles A Wood14 and Ellen R Stofan15, (1)University of California Berkeley, Berkeley, CA, United States, (2)Cornell University, Astronomy, Ithaca, NY, United States, (3)University of Virginia Main Campus, Charlottesville, VA, United States, (4)Organization Not Listed, Washington, DC, United States, (5)NASA Ames Research Center, Moffett Field, CA, United States, (6)Sapienza University of Rome, Rome, Italy, (7)NASA Ames Research Center, MS 245-3, Moffett Field, CA, United States, (8)Cornell University, Ithaca, NY, United States, (9)Massachusetts Institute of Technology, Earth, Atmospheric, and Planetary Sciences, Cambridge, MA, United States, (10)University of Idaho, Moscow, ID, United States, (11)University College London, London, United Kingdom, (12)USGS Grand Canyon Monitoring and Research Center, Flagstaff, AZ, United States, (13)Applied Physics Laboratory Johns Hopkins, Laurel, MD, United States, (14)Wheeling Jesuit University, Wheeling, WV, United States, (15)NASA Headquarters, Washington, DC, United States
Abstract:
Driven by an expansive atmosphere, Titan’s lakes, seas and accompanied hydrological cycle hold vast amounts of information regarding the history and evolution of Titan. To understand these features, we constructed a geomorphologic map of Titan's polar terrains using a combination of the Cassini SAR, ISS, VIMS, and topographic datasets. In combining SAR, ISS, and VIMS imagery with topographic data, our geomorphic map reveals a stratigraphic sequence from which we infer formation processes. In mapping both the South and North poles with the same morphologic units, we conclude that processes that dominated the North Pole also operated in the South. Large seas, which are currently methane/ethane filled in the North and dry in the South, characterize both poles. The current day dichotomy may result only from differing initial conditions. Regions removed from the mare are dominated by smooth, undulating plains, bounded by moderately dissected uplands that are discretized into observable drainage basins. These plains contain the highest density of filled and empty lake depressions, which appear morphologically distinct from the larger mare. The thicknesses of these undulating plains are retrieved from the depths of the embedded empty depressions that are up to 800 m deep. The development of such large deposits and the surrounding hillslopes can be explained by the presence of previously vast polar oceans. Larger liquid bodies would have allowed for a sustained accumulation of soluble and insoluble sediments from Titan’s lower latitudes. Two plausible evolutionary scenarios include seas that were slightly larger, followed by tectonic uplift, or oceans that were much larger, that have since lost most of their volume over time to methane photolysis. In either scenario, thick sedimentary deposits of soluble materials are required to have been emplaced prior to the formation of the small lake depressions.
