T39 (December 20th 2007 / Rev 54) Options

[Guest_Sunspot_*]

Why do so few flybys make uses of the radar? It seems it's the only instrument capable of making sense of what is generally happening on the surface. If I were on the RADAR science team I think i'd very frustrated at not being able to make more use of it.

[ugordan]

If I were on the RADAR science team I think i'd very frustrated at not being able to make more use of it.

I guess the ISS and VIMS folks would share the same feeling in their case...

[Guest_Sunspot_*]

I guess the ISS and VIMS folks would share the same feeling in their case...

Certainly during flybys of other Moons whose surfaces are revealed in spectacular detail by the cameras - yes, But not at Titan.

[Juramike]

Approximate location:

Thanks Olvegg!

So the area in PIA10219 is the SW portion of Mezzoramia.

The cool wrinkle pattern is very similar to what that interesting area in T16 ('bout 2/3 of the way to the left in the swath). In that region, it looked like like the wrinkle area was between two plains. From the dendritic pattern (look on the margins, otherwise the eyes get all goofed up by the optical illusion, positive relief or negative relief - aaargh!) it appears to go from the the plain on the left (southern) down to the plain on the right (northern) in T16.

It will be entertaining to stare at this new image, looking for similarities and contrasts in that area of the T16 Swath, and the T7 Swath of northern Mezzoramia.

Why do the valleys and braided streambeds look so different in T7 compared to the southern Mezzoramia region?

Is the lowest area in T7 the equivalent to the southern plain of T16?

What makes the Escher channel/ridge terrain? Is it due to rainfall erosion, subsurface erosion, or "melting" (melting, chemical modification, or dissolution all could fal into this catchall) of a cohesive component of the material.

Is this material some sorta dried weak slurry material that erodes quickly? Like sand on a beach? Or what is it?

Is Titan nothing but a bunch of goopy sloughs and islands?

Wow! I'm really thankful that they released this so quickly!

-Mike

[Stu]

Fascinating terrain... wow...

[Juramike]

Here are some graphics I whipped up of the T39 RADAR Swath section shown in PIA10219.



The first graphic shows estimated drainage pattern based on dendritic pattern orientation. Broadly, it is pretty much to the N, towards the Mezzoramia basin. But along the swath there are several drainage basin divides – almost like the surface shifted or dropped down into a series of puckers. Each pucker has its own little dendritic pattern. The broad patterns are indicate by the big blue arrows. The stream channels are indicated by red arrows. There is an orange area indicated that just doesn’t seem to fit in – more on this later.



The T39 Swath hit the SW section of Mezzoramia basin and the T7 Swath hit the N end of Mezzoramia basin. If the T7 Swath is turned upside down so that the drainage direction lines up, there are some similarities, as seen in the second graphic. One is that there are sediment filled puckers (or “dropouts”) like are seen in the T39 Swath. The only difference is that the puckers are filled with darker sediments in T7 and in the T39 swath they appear to have been subject to erosion so they have cute little dendritic patterns. Another similarity is that the RADAR bright sediment pattern near the basins appears simiar in the two swaths. This is seen in the following three slides:





The first slide shows the T7 bright pattern as one moves downstream near the basin (from left to right). The next two slides show similar patterns and are seen in the T39 Swath. The stream becomes bright on hitting the basin, then fans out and is criss-crossed by several dark lines. The RADAR brightness slowly fades on going further into the basin, possibly indicating sorting of materials over a very large distance. (Indicating extensive reworking?





The T39 RADAR Swath image shows a nice spectrum of different valley/ridge widths. An evolutionary sequence is shown in the graphic above. It all starts with an easily erodible upland, which is down cut into a karst-like terrain (image 1 and 2). The valleys perhaps hit a harder layer (maybe the erodible stuff is organic shizzle and the hard layer is “normal” crust/clathrate?) and then begins to widen (image 3). As the valleys widen, the ridges become sharer and narrower. (images 4 and 5). In image 6, very thin ridges remain which have been partially buried in infilled material. The locations where these images were plucked from is shown in the second graphic.




So presumably the thicker the intervening highland, the younger and less eroded the surface. Or, the thinner the ridges and broader the valleys, the older the surface. Since the “dropouts” or puckers seem to have only gentle alluvial networks, they seem to not have been heavily eroded. Perhaps they are made of different materials or they are much younger.


The last slide shows a zoom of the area around the orange indicated feature. Across the surface, there appears to be a uniform graduation of valley/ridge networks going from thin intervening ridges towards the south to thicker ridges (less eroded) towards the N central part of the image. The one exception seems to be where the orange-bordered terrain loos like it recently dropped out and filled in, messing up the uniform pattern. And perhaps that’s what happened. There was a slightly raised area that was subjected to erosion, then it suddenly collapsed and filled in. There does not appear to be any valley networks rushing into this new sinked area, although the bright line in radar indicates a substantial cliff. Other pucker areas seem to be located at drainage divides, thus the original surface prior to collapse must have been locally slightly higher. (Are these collapsed cryovolcano caldera??) This could be giving us a clue about the formation of at least the smooth type of lake, as well as some of the large dropout areas seen in W Xanadu, T7, and in the northern polar regions.

-Mike

[ngunn]

The T39 RADAR Swath image shows a nice spectrum of different valley/ridge widths. An evolutionary sequence is shown in the graphic above. It all starts with an easily erodible upland, which is down cut into a karst-like terrain (image 1 and 2). The valleys perhaps hit a harder layer (maybe the erodible stuff is organic shizzle and the hard layer is “normal” crust/clathrate?) and then begins to widen (image 3). As the valleys widen, the ridges become sharer and narrower. (images 4 and 5). In image 6, very thin ridges remain which have been partially buried in infilled material.

I'm not sure I follow you in detail here, but I tentatively agree with your observation that this looks like different erosion forms cut through (at least two) different materials.

[ngunn]

the methane rain on these plains certainly tore up the terrain

Sorry, couldn't resist:

'The rain on rough terrain drains mainly to the plain.'

'The rain on the plain flows mostly down the drain.'

Somebody stop me . . .

[Gladstoner]

Wow. I didn't realize that Canyonlands National Park has a counterpart on Titan:

Google Maps - Canyonlands National Park

Utah's version even has an impact crater (Upheaval Dome).

[Gladstoner]

And is it me, or are there lobe-shaped features that somewhat, though vaguely, resemble the Eberswalde delta complex on Mars? :



With the vast amount of fluvial erosion on Titan, such features should be expected where rivers reach base level.

Also, the bright 'lslands' at the top of the image are quite striking. Is the demarcation a current shoreline? Or is it a 'high methane mark', where rough 'rock' lies above an exposed smooth, mud-covered lake bed? Or is it something else entirely?

Goodness, it sure is wonderful to see bewilderingly complex territory for the first time.

[belleraphon1]

Sorry, couldn't resist:

'The rain on rough terrain drains mainly to the plain.'

'The rain on the plain flows mostly down the drain.'

Somebody stop me . . .

Actually ngunn, that sounds pretty abt!

Juramike... great work as usual.... all that schizzle and smurst and icy bedrock getting churned over the eons... no wonder the terrains on Titan are so diverse.

Sunspot.... we cannot understand the surface without knowing what the atmosphere is doing and what all that schizzle soup is made of... we need VIMS/ISS/INMS.... all the instruments, because this is a world....

Just SO thankful we have this wonderful CASSINI and all the folks involved in this mission..... and thankful this was released so quickly given the holidays....

Craig

[volcanopele]

Well, what do you know

http://photojournal.jpl.nasa.gov/jpeg/PIA10219.jpg

I knew that river looked familiar: http://photojournal.jpl.nasa.gov/catalog/PIA06202

At least one of the little squiggles I drew actually turned out to be a river channel.

[ngunn]

I note that the caption to the south pole image refers to the hypothesis that the north-south difference in lake numbers is a temporary seasonal phenomenon. While I liked that idea for a time I thought it had been ruled out because there is just not enough heat available to evaporate so much liquid in one seasonal cycle. Is the thinking on this changing again, or is the caption writer just making passing mention of an earlier idea?

To me it looks as if most of the drainage channels in the south polar 'highlands' specifically avoid the few lakes that seem to be present. In other words everything drains northward from a regional topographic high near the south pole - except for a few enclosed basins that can't drain, and therefore contain lakes. That makes sense if the poles are areas of net deposition of solids as suggested in the recent CHARM presentation. Is it then the great northern lakes that are the anomalies, since these require recent or ongoing downwarping of the crust on a regional scale to maintain their basins?

[DrShank]

I note that the caption to the south pole image refers to the hypothesis that the north-south difference in lake numbers is a temporary seasonal phenomenon. While I liked that idea for a time I thought it had been ruled out because there is just not enough heat available to evaporate so much liquid in one seasonal cycle. Is the thinking on this changing again, or is the caption writer just making passing mention of an earlier idea?

To me it looks as if most of the drainage channels in the south polar 'highlands' specifically avoid the few lakes that seem to be present. In other words everything drains northward from a regional topographic high near the south pole - except for a few enclosed basins that can't drain, and therefore contain lakes. That makes sense if the poles are areas of net deposition of solids as suggested in the recent CHARM presentation. Is it then the great northern lakes that are the anomalies, since these require recent or ongoing downwarping of the crust on a regional scale to maintain their basins?

[ngunn]

And your comment, DrShank? I'm all ears.