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Updated Titan Map
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post Jan 1 2007, 03:09 AM
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Yeah, JR--I used to live in Tucson, and that's exactly the same impression I got. The entire area is usually dry as a bone all year until monsoon season hits in June/July, and then it's flash-flood time which produces/reinforces all these massive arroyos. Perhaps the same thing happens in Titan's equatorial regions every 14.5 terrestrial years or so...


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Juramike
post Jan 2 2007, 08:35 PM
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Does anyone out there have a hypothesis/explanation for the distinctly swoopy pattern of the overall look of the margin of the of the bright terrain against the dark terrain?

It seems that the bright features have an almost parallel aerodynamic look to them. This is particulary evident in the margins around Shangri-La (basin).

This has been fascinating me since the first pass: to my eyes, they look almost like a terrestrial fjord landscape.

Could this be resulting from wind deposition of upland (bright) material from cryovolcanic airfall?
Or could this be from wind deposition of the organic “shizzle” which piles up downwind against the bright material?
Or is it possible that there has been an equivalent of a past ice age on Titan, with methane snows piling up, forming methane glaciers, and coming down off Xanadu and other upland terrains?

Any ideas?

-Mike


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Bob Shaw
post Jan 2 2007, 10:54 PM
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QUOTE (Juramike @ Jan 2 2007, 08:35 PM) *
Does anyone out there have a hypothesis/explanation for the distinctly swoopy pattern of the overall look of the margin of the of the bright terrain against the dark terrain?

It seems that the bright features have an almost parallel aerodynamic look to them. This is particulary evident in the margins around Shangri-La (basin).

This has been fascinating me since the first pass: to my eyes, they look almost like a terrestrial fjord landscape.

-Mike


Mike:

I don't quite know what 'swoopy' landforms are like, but as for the rest it looks just like the west coast of Scotland - a fjord landscape... ...AIRC, 'Scotland' was indeed one of the nicknames used back in the early days!


Bob Shaw


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JRehling
post Jan 3 2007, 03:29 PM
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QUOTE (Bob Shaw @ Jan 2 2007, 02:54 PM) *
Mike:

I don't quite know what 'swoopy' landforms are like, but as for the rest it looks just like the west coast of Scotland - a fjord landscape... ...AIRC, 'Scotland' was indeed one of the nicknames used back in the early days!
Bob Shaw


I just went back to the Planetary Sciences Yahoo! group and saw that at 4:09pm on July 2, 2004, I posted:

"Image N00006513.jpg... first thing I think of is a map of Scotland."

That was about 2 1/2 hours after the first images came down. Took a while to de-haze them enough.

My half-considered explanation for the Scottish shape would be that tectonic uplift in this area caused a lot of faulting with the same orientation, with the crust buckling according to different spatial frequencies. Large-scale buckles give the overall shape of Xanadu's northwestern "coast" while small-scale buckles make the whole thing look like corduroy... as do various locations up the Pacific Coast of the Americas, Scotland, and other places on Earth.

One of the interesting things is that Xanadu has moderately dark "lochs" near but not part of (or as dark as) Shangri-La. Probably the same sediments that darkened Shangri-La, but in lesser amounts.
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Juramike
post Jan 3 2007, 06:22 PM
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QUOTE (JRehling @ Jan 3 2007, 10:29 AM) *
My half-considered explanation for the Scottish shape would be that tectonic uplift in this area caused a lot of faulting with the same orientation, with the crust buckling according to different spatial frequencies. Large-scale buckles give the overall shape of Xanadu's northwestern "coast" while small-scale buckles make the whole thing look like corduroy... as do various locations up the Pacific Coast of the Americas, Scotland, and other places on Earth.

One of the interesting things is that Xanadu has moderately dark "lochs" near but not part of (or as dark as) Shangri-La. Probably the same sediments that darkened Shangri-La, but in lesser amounts.



So, the tectonic uplift causes the general buckling....and then the infilling of the lowland basins by the dark material causes a ria (drowned valley) topography?

In this case the drowning of the valleys is caused not by a rise in seawater (like on Earth), but by the gradual infilling of the the dark material basins due to the organic "schizzle" raining down?

[Thus the dark lochs are shallower accumulations of the organic ooze.]

Or is a glacial event still a possibility?

-Mike


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Bjorn Jonsson
post Jan 3 2007, 11:17 PM
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QUOTE (JTN @ Dec 30 2006, 11:16 PM) *
I've always been surprised that there aren't more amateur Titan ORS mosaics here. (I realise it's a bit of a challenge, but that doesn't usually stop you lot...)

Yes, this is very surprising. In my case one reason is that all of my recent Cassini image processing has involved a huge map covering Saturn's entire southern hemisphere. See this thread, especially the message I posted there today.

QUOTE (ugordan @ Dec 31 2006, 12:06 AM) *
Surprisingly, there aren't a whole lot of people playing around any Cassini images that I can see. Titan would make a pretty hard target to work with, given no easy way to reduce atmospheric haze. You really need excellent flatfields and either you can brew your own ones (hard to do manually) or work with the not so good ones on the calibration volumes. There's a lot to be desired there, especially for the wide-angle camera flatfields which would make simple mosaics easier than taking a shot at high-res NAC footprints. Geometric reprojection would also be handy since the exposures are long and the flybys pretty fast. SPICE kernels in other words...

One idea might be to reduce noise by reprojecting several images of the same (or roughly same) area into a simple cylindrical map containing their 'sum' (a similar idea to superresolution processing). However, this requires extremely accurate pointing information since there are no high contrast features to use as an accurate guide if the results of reprojecting two or more images don't exactly match. The Cassini index files (index.tab) contain viewing geometry information but when making the previously mentioned map of Saturn I got slightly more accurate results by using the SPICE kernels directly.
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post Jan 17 2007, 01:10 AM
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Edit: Sorry, didn't realize the map had already posted. Should have read the earlier posts.
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scalbers
post Jun 21 2007, 09:47 PM
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Greetings,

Here's a real quick 1K Titan map taking the latest official one from late 2006 and overlaying mosaics from a couple of the recent flybys. As usual this can be refined in the future. Perhaps even some north polar radar mosaics can be added if they are on a suitable projection - a certain map I noticed from EC comes to mind.

http://laps.noaa.gov/albers/sos/saturn/tit...cyl_070621c.jpg


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David
post Jun 22 2007, 12:04 AM
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QUOTE (scalbers @ Jun 21 2007, 09:47 PM) *
Greetings,

Here's a real quick 1K Titan map taking the latest official one from late 2006 and overlaying mosaics from a couple of the recent flybys.


Very nice!

But it gets me thinking again about the global distributions of different terrains and climates on Titan. The overall picture seems clear: Titan is a semi-desert moon, wet at the poles, very dry around the equator, with an equatorial belt of sand-seas in (it seems) lower terrain. Which raises the following questions for me:

1) Why is the equatorial belt so irregular in shape? Just chance variations in elevation?

2) What constrains the desert belt to north and south? Or to put it another way, what's going on in the temperate zone in terrains that would be deserts if they were equatorial?
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stevesliva
post Jun 22 2007, 04:53 AM
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That's nice!

Although a mercator projection centered at the equator distorts exactly what is interesting at Titan... wink.gif
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Juramike
post Jun 22 2007, 03:00 PM
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Wow! Nice job!

-Mike


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Juramike
post Jun 22 2007, 03:15 PM
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QUOTE (David @ Jun 21 2007, 08:04 PM) *
1) Why is the equatorial belt so irregular in shape? Just chance variations in elevation?


Elevation differences, yes. Chance? Maybe not.

I suspect Xanadu might be playing a role. It might be acting like Tharsis bulge on Mars. Big cryovolcanic construct, big mass put on surface, gets drifted to equator. Why the Sand Seas are where they are on either side of Xanadu and in approximate line with the Equater is bugging me too. The pattern of Tharsis/Vallis Marineris on Mars and Xanadu/Fensal-Quivra-Azltan = "The Big H" on Titan is eerily similar.

Also, since we haven't imaged all of Titan in really good detail, there could be other low-lying Sand Seas in temperate zones as well. (And what would a raised Sand Sea basin look like?) Mezzoramia might be one of these.


QUOTE (David @ Jun 21 2007, 08:04 PM) *
2) What constrains the desert belt to north and south? Or to put it another way, what's going on in the temperate zone in terrains that would be deserts if they were equatorial?


A really good question! Is it elevation? Or is it methane rainfall? Or is it something else entirely? (Maybe the sand sea basins are "special" and the "normal" surface is like the temperate zones.)

-Mike


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dvandorn
post Jun 22 2007, 04:13 PM
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Interesting speculation, Mike. I see your point about the similarities between the Xanadu/Fensal-Quivra-Azltan construct and Mars' Tharsis bulge.

However -- just how efficiently could Titan shift its orientation when locked into a tidal resonance with Saturn? Mars spins very fast, relatively speaking, and has a whole lot more rotational energy with which to shift the entire planet onto its side (so to speak). Titan, in contrast, spins very slowly on its axis and has the very deep Saturnian gravity well to deal with. I'd almost believe that tidal attraction from Saturn would supply more energy to such a process than Titan's own rotational energy could provide.

If Titan's mass was redistributed in a manner similar to what happened on Mars, I'd be willing to bet you'd see the thing reach an equilibrium with the "heaviest" part of the mass tidally locked, facing Saturn. Is that what we're seeing here? If not, I have to wonder a bit as to how the mechanism would work...

-the other Doug


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Juramike
post Jun 22 2007, 06:53 PM
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That's a really good point, David.

Without doing the math (yuk!), I'd guess tidal effects (including eccentricity) would swamp out the rotation rate.

So I'd guess it would make more sense for the Xanadu bulge to be at either the Subsaturn point or at the AntiSaturn point. And at longitude 90-100 W, it's pretty much in the wrong spot.

Now I'm even more clueless.... huh.gif

-Mike


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dvandorn
post Jun 22 2007, 06:57 PM
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I'm glad I could confuse you even moreso than before, Mark... wink.gif

-the other DOUG (smile.gif)


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