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| Xanadu Is Old, Rugged And Low-lying |
| Presentation Time: Thursday, 9:10 a.m. - 9:20 a.m. |
Charles Wood1, R. L. Kirk2, E. Stofan3, B. Stiles4, H. Zebker5, S. Ostro4, J. Radebaugh6, R. D. Lorenz7, P. Callahan4, S. Wall4
1Wheeling Jesuit Univ. & Planetary Science Inst., 2U.S. Geological Survey, Astrogeology Program, 3Proxemy Research, 4Jet Propulsion Laboratory, 5Stanford University, 6Brigham Young University, 7Applied Physics Lab.. |
| Presentation Number: 44.05 |
| Xanadu was the first surface feature discovered on Titan. It is anomalously bright in the IR, and is also radar bright with unusual physical properties. Xanadu is continent size (~4000 km wide) with a sharp boundary to the west against the dark dunes of Shangri-La, and less distinct boundaries in other areas. Because of its size and reflectivity it had been proposed that Xanadu is an elevated continent. But it is not. A new topography-from-SAR technique shows that along the T13 Radar swath which completely transects Xanadu, the average topographic elevation is indistinguishable from that of the surrounding terrain. There are many mountains with peaks locally rising up to 1-2 km, but the average elevation of the T13 pass is 200 m +/- 300 m lower than the radius of Titan. The highest point is near the swath center. Photogeologic interpretation suggests that Xanadu slopes to the south; three major river systems begin in the north and flow southward. The lack of significant average elevation means that it is not necessary to create models to explain how Xanadu is dynamically supported. Its eroded-looking terrain, large number of possible eroded impact craters, dune encroachment on its western edge, and apparent detached patches of similar material near its margins all suggest that Xanadu is a relict terrain, currently being disaggregated. The only sign of current activity is the river channels. We speculate that Xanadu was originally a landform of higher elevation (2 km higher if the mountain tops are remnants of an original surface) that has been modified by erosion and/or isostatic adjustment. If the observed river systems have eroded and removed the putative higher terrain there may be significant sediment deposits in the central or southern parts of Xanadu, and/or this material may have been redistributed by winds. |
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