[X] My Assistant

[volcanopele]

Well, for those who really like RADAR SAR swaths, today is a good day for you. The T13 RADAR swath from April, THE ENTIRE SWATH, has been publically released on the Photojournal.

Titan (T13) Viewed by Cassini's Radar - April 30, 2006
http://photojournal.jpl.nasa.gov/catalog/PIA08552

PIA08604: Xanadu's Meandering Rivers
http://photojournal.jpl.nasa.gov/catalog/PIA08604

PIA08605: Titan's Geological Goldmine - Radar Movie
http://photojournal.jpl.nasa.gov/catalog/PIA08605

[volcanopele]

A few comments on some of the amazing features seen in this swath (my favorite thus far) as well as a comment on the movie.

First, regarding the movie: in the movie, they highlight a few of the intriguing features seen in the swath, particularly the Xanadu east and west "coasts". While these may be the margins in RADAR, they are not the margins at IR wavelengths. The west margin basically matches, though the upper portion of the margin in the swath does not match. Part of the IR-bright Xanadu terrain appears dark. The eastern margin doesn't match AT ALL. The IR margin is actually beyond the eastern end of the swath. There are no IR traces of the RADAR margin on the eastern side. Again, the one constant of broad IR dark terrain (not the small patches, which can appear hilly, smooth, rough, etc. in RADAR) is that they are covered in longitudinal dunes.

Now on to the swath itself (for the rest of this discussion, note that RADAR illumination is from above). One thing I love about this swath is that it has "real" topography. Sure, the others did as well, but this one has honest to goodness plateaus, and other really cool geomorphology. In this first image, below, you see some plateaus just east of the river systems in western Xanadu. The most prominent plateaus is along the top of the swath on the right side of this cutout. What is neat is that you can see several streams starting out at the bottoms of canyons along the plateau margin. You can also see this at a smooth topped plateau to the southwest. Throughout this area, you can see plateaus with canyons along their margin, which suggest that methane can erode into the surface and these rivers can form in much the same way that river do on earth.



In this next cutout, we see a patch of hills at the eastern end of the RADAR swath. This isolated hills are located within an area of smooth, bright terrain in eastern Xanadu. Emanating from the hills are three radiating channels (though the ones to the west and south may be the same channel diverting around the patch of hills.



This swath also appears to have a number of apparent impact craters. The third image below shows a few of them, though it can't be ruled out that some or all of these are actually cryovolcanoes. This view also reveals the smallest impact crater revealed thus far at around 15 km across (the bottom left one). The bottom right crateriform is Guabonito. The top right has an apparent central peak, but the extension of smooth material from its southwestern margin has led to the suggestion that it might be a cryovolcano. the crateriform at top right may be a viscously relaxed crater where only its rim is still visible.