Geological Society of America

T84 Ice in the Solar System: Mars to Pluto and Icy Worlds in Between

Sunday, 19 October 2014
1:00 PM - 5:00 PM
301

LABYRINTH TERRAIN ON TITAN

Paper number: T84-6
Program: Technical Sessions
Time: 2:05 PM – 2:20 PM

Authors

Michael J. Malaska Presenting Author
Jet Propulsion Laboratory/California Institute of Technology, Pasadena, CA
Jani Radebaugh
Brigham Young UniversityDepartment of Geosciences, Provo, UT
Rosaly M.C. Lopes
Jet Propulsion Laboratory, CalTech, Pasadena, CA
Karl L. Mitchell
California Institute of Technology, Pasadena, CA
Alexander G. Hayes
Cornell University, Ithaca, NY
Alice Le Gall
Universite Versailles Saint-Quentim (UVSQ), Guyancourt
Elizabeth Turtle
John Hopkins University, Laurel, MD
Anezina Solomonidou
California Institute of Technology, Pasadena, CA
Ralph Lorenz
Johns Hopkins University, Laurel, MD

Abstract

Saturn’s moon Titan has a thick atmosphere that supports a meteorological cycle of liquid hydrocarbons. We have identified a highly dissected terrain unit on Titan called Labyrinthic terrain. This unit covers less than 5% of the surface area of Titan, but may reveal much about the geological history of that world. This terrain type consists of dissected plateaux and remnant ridges with a high relative valley density when compared to other terrains on Titan observed at a spatial resolution of about 350 m (the maximum spatial resolution for the Cassini Synthetic Aperture Radar mode). These terrains have a medium to low radar backscatter when compared to other units on Titan. Radiometric data from the same instrument suggests materials that are not consistent with water ice.

Labyrinthic terrain units are consistently locally elevated compared to the rest of Titan’s terrain units. This suggests that these units are either ancient terrains that survived regional deflation, or that they have been uplifted and dissected by erosion, likely fluvial. The Labyrinthic terrain units are always associated with Titan’s undifferentiated plain units. The plains units form the valley fill, and are at the margins of Labyrinthic terrains where valleys debouch out onto the plain. While Labyrinthic terrains could be the source for some of the plains material, some type of modification needs to occur in order to explain the spectral properties. Inside several of the Labyrinthic terrain units, closed valleys can be discerned, consistent with mass removal by some process, possibly by dissolution and/or suffosion. The various Titan Labyrinthic terrain units all have strong morphological similarity to terrestrial karst terrains. We suggest that Titan’s Labyrinthic terrain is a type of terrain unit that has been subjected to chemical dissolution and physical erosion to then produce the materials that are deposited onto surrounding plains, forming the plains unit. Since water ice is not expected to be dissolved by hydrocarbon solvents, we further suggest that the Labyrinthic terrain unit is composed of an uplifted organic sedimentary deposit that can be partially dissolved. We propose that Labyrinthic terrain is a part of the organic sedimentary cycle on Titan.