T28 (April 10th 2007) Options

[Juramike]

The Dancing Monkey feature located in the bright temperate highland area N of Adiri (approx location [30N, 210W]) looks very much like a cycloid crack pattern as seen on Europa.
Here are is an image of the Dancing Monkey feature (clipped from the CICLOPS website in the Looking Ahead Rev 47 post). And here is an image of a similarly complex patterned area on Europa.



It is thought that the cycloids are generated by diurnal tides. (Europa orbits Jupiter every 3.55 days). Each arc is generated in one orbit due to changing and rotating tidal forces. The area on Titan and the area imaged on Europa are in almost the same tidal force environments (same longitude, almost exact opposite latitude). [Fun fact: (0N,0W) is the subprimary point for rotationally locked moons.] See this post for diagram showing Titan’s tidal forces and this post showing where the forces in Titan are strongest.


Cycloid cracks are now thought to result from rotating tensile and shear stresses (Marshall and Kattenhorn Icarus 177 (2005) 341-366. “A revised model for cycloid growth mechanics on Europa: Evidence from surface morphologies and geometries” HTML (text-only no pictures - freely available here (A earlier work describing strike-slip faults on Europa is available freely here). A diagram of the cycloid growth model proposed by Marshall and Kattenhorn is shown below:



At a certain point, the tensile strength of the crust (ice) breaks and a crack forms and propagates. If the forces rotate faster than the crack propogates, the crack will try to form an arc. But as the forces rotate faster, they set up a shear as the tidal pull yanks the material on one side of the crack. The crack then begins to behave as a slip fault. Eventually the tensile force decreases, the crack stops propogating. But the forces keep rotating and eventually set up a shear in the old crack, and a tensile stress in the terminus. The shear forms a “tailcrack” and the crack propogates again. This makes a line with a series of arcs hopping across the surface.

From the article, I got the impression that faults and cycloid cracks on Europa might be two flavors of the same thing.

Also, cycloid cracks have recently been observed on Enceladus’s south pole: Hurford et al. LPS XXXVIII (2007) Abstract 1844. “A cycloid-like rift near Enceladus’ South Pole: Europa-style Production by Tidal Stress.”. Abstract freely available here.

-Mike

[Juramike]

Europa-like cycloid crack propagation may be responsible for the evolution of the Dancing Monkey feature as shown in the following putative formation sequence. This final steps of this sequence are pretty much the same as proposed for the putative formation sequence for the neighboring Sliced Carrot feature (described in this post), save for the atmospheric chemistry product deposition:











Here are the steps in the putative sequence:
1) Cycloid cracks start
2) Cycloid cracks propagate (1 arc/orbit)
3) Cycloid cracks continue (Tectonic faulting also?)
4) Network widens
5) Erosion from runoff cuts/shapes makes new channels (river capture?): dark blue ice sands deposited
6) Bright material deposited
7) Inundation and flooding by hydrocarbon solvents removes bright material from below flood stage
8) Dune sands invade system
9) Atmospheric chemistry products brought down by seasonal rains: deposition over dune sands and bright highlands: contrast lowered.


(The exact formation sequence of the network will be very tricky to work out. Different cracks may have formed at different times. Shifting and faulting may also have occurred to complicate matters).

Here is a comparsion of the diagram from the sequence above with the observed image:



The Dancing Monkey feature is probably an overall shallow area that has cracks just at the right level to be inundated by flood events that removed the bright material and increased contrast. Rather than a series of canyons and hoodoos, the feature most likely resembles a low-lying series of backwater sloughs. (using the “western US” definition of slough. Earth analog: Elkhorn Slough wiki here: http://en.wikipedia.org/wiki/Elkhorn_Slough)

We may expect to see more regions of cycloid cracks on Titan. The area directly to the SE of the Dancing Monkey feature may have formed similarly but lying slightly lower, was subject to more extensive erosion from fluvial and tidal effects of the Equatorial Sand sea basins.

It might be interesting to see if any of the ridges or grabens have a cycloidal or arcuate pattern overprinted on them. (T8 RADAR swath ridges that look like ski tracks? Or the "tiger stripes" river paths waaay up north?)


-Mike

[edstrick]

Why do I keep thinking it looks like the Flying Spaghetti Monster....?

[Phil Stooke]

That was my thought too. Anyone for pasta?

Phil

[edstrick]

It's only a fake flying spaghetti monster....

....so it's an im-pasta!

[ugordan]

Apologies if this was already mentioned somewhere, but the full T28 RADAR swath was released today:
PIA09217

[ngunn]

Thanks ugordan - it's a beauty.

[belleraphon1]

I was just going to post this.....

thanks uugordon.

Hopefully this is a harbinger of more releases to come?!?!.

Craig

[Juramike]

Awesome!

Wher is this located on Titan?

Anybody got an global map with the T28 RADAR swath indicated?

-Mike

[belleraphon1]

Mike..

looks like this starts in Tsegihi and crosses Aztlan and Fensel as it heads north east.

See slides 14 and 16 in this last CHARM presentation

http://saturn.jpl.nasa.gov/multimedia/prod...CHARM_3Year.pdf

Anybody have radar swath maps that are labeled?

Craig

[rlorenz]

Hopefully this is a harbinger of more releases to come?!?!.

Yes.

[belleraphon1]

Yes.

More Please!!!!!!!!!!

[Stu]

the full T28 RADAR swath was released today:

Some highlights of the lakes area... as usual, purely for "wow" reasons, not suggesting any scientific worth, ok?

[belleraphon1]

Calling all image mages.... ALERT ALERT ALERT.....

Can some one line up http://photojournal.jpl.nasa.gov/catalog/PIA09217 from T28
with http://photojournal.jpl.nasa.gov/catalog/PIA09182 from T25?

And very evocative images Stu....

Amazing little world.... I am constantly amazed seeing these swaths.... as lively a place as we could wish for....... I was commenting to a coworker how wonderful these data are and I still have to pinch myself to be sure this is not some science fiction dream. This is for real....

Craig

[Juramike]

Hey Craig,

I think I got the lower part (I stuck it in the Equatorial Sand Seas thread) here:

(T25 was in the Exploitcorporations mosaic, you may may need to enlarge it to see the T25 insertion. It is immediately to the W of the T28 swath, and also has Sotra Facula at its lower section)

-Mike