PDA

View Full Version : Discussion: Fractured Crater on Mars



Fraser
2004-Jul-27, 05:16 PM
SUMMARY: This perspective image of a fractured crater near the Valles Marineris was taken by the European Space Agency's Mars Express spacecraft during its 61st orbit in January, 2004. The image was obtained using its High Resolution Stereo Camera (HRSC), which enables scientists to build a realistic 3D model of the surface of Mars which can then be tilted and rotated to examine from different angles. Scientists aren't sure why the floor of this crater is broken up like this, but it could be from cooled lava, dried clay, or frozen ground.

What do you think about this story? Post your comments below.

Guest
2004-Jul-27, 07:43 PM
nice picture B)

lswinford
2004-Jul-27, 08:10 PM
For what its worth, I'll take a stab at this. So there is a crater ring and an eroded caldera dome. Assume for the moment that Mars had surface and atmospheric water at some point after this feature was formed. In the upper-center of the dome a depression appears to feed a four-way flow. The rains or snow melts would either branch away from view into one of three streams or down toward the viewer in one stream that essentially branched into two. In the large relatively flat mass above and to the left of that latter stream bed there appears to be smaller minor streams. One runs down the base of the crater ring wall and the other bisecting that relative plain to join to the main stream half-way between the major branching. Similarly several such minor streams take surplus runoff away from the primary flow cuts. That right-hand center land mass may also have had some sheeting runoff begining and sustaining the major gash and branch close to the viewer. A somewhat alternate picture, however, is that there was a canyon-cutting river and an upwelling magma dome caused a curve (around and to the left) in the river's flow. But, it looks like an impact crater to me.

Guest
2004-Jul-27, 09:42 PM
The river idea wouldn't work I think, there is no way out for the water (and no source either). I didn't look at the 3D version, but it seems that the "cracks" are not following a gradient, it seems that the "cracks" follow the terrain up as well as down, just going along with the contours that were apparently already in place. There is nothing that I know of that, by flowing can create these features. The meandering makes it unlikely that they really are cracks formed by faults and "sinking" (not the right word but I hope I make sense).
So what else do we have for an explanation.
The resident planetary scientist maybe, Duane any ideas?
Or maybe the vulcanologist, Damienpaul.
Or do I have to resort to the exotic electric explanation? ;)

Cheers

lswinford
2004-Jul-27, 10:09 PM
You may be right. But the contours of the land as I saw it were my summation without real points of reference. However, the softness of the lines and the curves still look more liquid than broken to me. The up and down of the flow, however, I admit to be just guess. The jaggedness of the major lines is not strange to fluid flow, but neither are the curves and wispy-ness of the lines below the dome (or whatever you want to call the center highland). The jagged ravines, as I imagined them, would not be strange to a soft-soil hilltop on earth after a heavy rain or a quick melt of a heavy snow. But then I can't be dogmatic about it. I remember getting chewed out by a geology teacher when I tried to describe a subject scene with things not in the picture, "I don't care if the moon falls over there [outside the picture] what happens with what you see here?!" However, part of the story for the same scene on earth has a multitude of references. Snapshots from Mars are a tad stranger, wouldn't you say?

Duane
2004-Jul-27, 10:29 PM
The word you meant is subduction VanderL :)

I copied the high resolution picture so I could look closely at the features within the crater. Based I what I see I can venture a couple of guesses.

Looking at the top left of the image, roughly 1/3 to 1/2 way up the crater wall I can see evidence of wall slumping. Directly under that slump I can see the beginning of 3 "channels" (for lack of a better word), two seeming to merge a short way into the crater and a third one seeming to run along the edge between the crater floor and wall.

Considering the location of the crater and its apparent slope from the top of the image towards the bottom of the image, it appears to me that some kind of liquid, probably water, was released. The caused the overlying material of the crater wall to slump down towards the crater floor, and because of the angle of the floor, the liquid flowed towards the center and off to the left.

It also appears that there were at least two, maybe three, different flows from the same area. I say this because the right channel seems to have been overflowed towards the left channel, heading towards the left side of the crater. Following that flow, there is a nodual that looks very much like a flow front, which in turn seems to overlay a bigger flowfront. There seems to have been some pooling in this area.

Going back to the slumped crater wall area, and following the flow line down the middle of the crater, is seems to have flowed past an upraised area in the center (dome maybe?) then continued down and split again around another upraised area towards the bottom of the crater, where it pooled. It looks like the pooling reached the point where it overflowed the crater wall, flowing in a wave over the wall and down the slope.

I do not see evidence of a central peak as you would expect from an impact, nor can I see evidence of an ejecta blanket. This suggests to me that we are looking at an ancient caldara that probably collapsed as the magma dome retreated back into the core. Periodic upsurges of the magma dome could account for the heat needed to release the water from the crater edge(s).

I note there are impacts within the crater, suggesting it is very old, but I also note some impacts overlay the channels while others appear to have been degraded by whatever flowed through them. This would suggest the caldera formed first a few hundreds of million years before the flow appeared, and that the flow itself is quite young, a few million years old or so.

Looking to the bottom right of the image, where the flow appears to have pooled, I see evidence of flow leading away from the crater downslope. The flow here is larger and less defined, suggesting a lahar-type flow from the crater.

There are no visible craters in the flow area, suggesting it is about the same age as the channels, maybe a bit younger. Again, this could be the result of multiple flows.

Eric Vaxxine
2004-Jul-28, 10:45 AM
What is the dark material on the left. dead algae?

VanderL
2004-Jul-28, 03:43 PM
Thanks Duane,

Subduction right (subdued :unsure: ), your explanation seems totally logical, however I have 4 questions:

1. What are those craters doing in the top of the image (the ones perched on the rim) are those impact craters? Please explain how they form that line between them.

2. Just below those craters we see what you would describe as wall slumping, what I see is that the river/crack/whatever-we-call-it runs along the rim upwards (the same process that created the "riverbeds", created the "rim feature", imo). I don't how to explain it but it seems the river runs under an angle! (A bit like those bikes speeding inside a cylinder on the carnival, many years ago)

3. Below that there is a "river" running to the right (or to the left depending on your view), crossing another "river" while at the same time becoming shallower (running upwards?). Finally after crossing another "river" it peters out. Conversely you could think that what I described as the ending, actually is the startingpoint of that flow. But that would mean it started in the middle of nowhere, without anything "feeding" it.

4. The broadening and narrowing of the "rivers" don't seem to correlate with depth.

I hope you can see what I mean, I would like to include a picture, but I don't see the buttons to post a picture anymore.

Cheers.

Duane
2004-Jul-29, 01:40 AM
Sorry I'm not sure where you mean, nor can I see a line going between any craters. The peak of the hill is to the top middle left, the 2 legs of the "river" leading from the "slumped wall" is nearly dead centre top. Can you point me to where you mean using those references?

VanderL
2004-Jul-29, 09:36 AM
The peak of the hill is to the top middle left, the 2 legs of the "river" leading from the "slumped wall" is nearly dead centre top. Can you point me to where you mean using those references?

Ok I'll try, it would be nice if I could insert an image but I don't know how (anyone?).

The craters are on the rim at 11 o'clock (the connection is a ridge), and the river that crosses other riverbeds is near the bottom of the V from the upper 2 legs (12 0'clock and then down towards the middle of the image). You need the high resolution image to see what I mean.

I'll try to find a 3D animation to get an idea how the terrain in the crater is tilted, I presume it is highest in the top of the image, and in the middle of the crater.

Cheers.

Duane
2004-Jul-29, 03:45 PM
Ok, here is the image:

http://esamultimedia.esa.int/images/marsexpress/s_022_120704_0061_4_3d_01_FracturedCrater_Geo.jpg

1) Ok, I think I see where you are talking about, however I don't think that those features are craters--they look more like deformations consistant with wall slumping. This would be consistant with the area immediately below those structures subducting, thus allowing the material overtop to slump.

2) It's hard to tell due to the lack of relief, however it looks consistant with a landslide--you can see the slump of the slope and the rundown of material towards the crater floor--it almost looks like it has folded over the material below it. Furthermore, you can see an apparent edge to the landslide further into the crater, and the material of the slide has been cut by the apparent flow channels.

3) I think the "river" is running from right to left, and overcuts the 2 legs. Again, consistant with episodic release of liquid from (or around) the crater wall area just to the left of the peak. The 2 legs occured first, then the area where they initially ran was uplifted by magma intrusion into the magma chamber--the uplift caused the next period of release to divert across the first flow channels and follow the topology to the left. It diverted around and then through the leading edge of the landslide, joined up with the older channel already carved along the crater wall, and pooled by the far left crater wall.

4) The broadening and narrowing don't necessarily correspond with depth, rather they may indicate flatness--the stream widened as it reached flatter land. Again, it is hard to tell due to the lack of relief--you cannot tell if the channels are wider and deeper, or wider and shallower or a combination. I do note that there are channels which appear to have been partially filled--maybe episodic volcanism, or flooding, or a combination of both.

VanderL
2004-Jul-29, 04:26 PM
Wow,

How can miss that image, ok I see what you mean regarding the craters at the rim, they only look
like craters. The river crossing the others is a little more difficult, because I can't see anyplace that the first stream must have originated (nothing connected to the crater wall), and what I don't see is how the channel and smaller channels "against-the-upper wall" can form through slumping. They have distinct meandering features and are tilted. The slumping looks only a minor detail superposed on the "flowchannel-rounding-the-curve" feature".

The channel crossing other channels is something I have seen (and questioned you on) before and what bothers me about them is how fast they seem to carve downward into the rock and how little they disturb the sharp edges and steep walls of the channels they cross.
Anyway thanks for the explanation, if you have time maybe there are some (links to) other pictures that can show how this slumping works and how channels cross other channels.

Btw, are you "privileged" to upload images, or am I too stupid to find the buttons. :D

Cheers.

lswinford
2004-Aug-02, 10:24 PM
That close up blew me away, awesome!

Now I'm more confused than ever. I'm following the V's of the flow branches to point downstream but then there are those pooling places near the crater rim that would seem to be where the streams empty into, except the directions are screwy to what would be obvious guesses.

But when I looked at the area between two branches below the gap at the top of the crater rim ring, there was a blue patch, that were I looking at an earth picture I would swear that was a body of water. But surely not in this context. It is above that dark-brown sluffing from the left bank of the left one of those branches below the 'notch' or 'gap'. Its on the upper west coast of that wedge-shaped block that resembles India.

Guest
2004-Aug-05, 08:24 AM
I think the rivers are really strange features, that's why the title is probably "cracked" Crater on Mars. Here is another example of a strange river
this (http://images.spaceref.com/news/2004/20040804A.jpg) is an image showing a central mound of a crater with something resembling a river cutting through the mound.
Several features make it strange, the channel on the left side is quite deep and broad, and it has extremely short and deep "tributaries" (the right part of the broad channel).
Further to the rightit is connected to a much narrower channel and it's flow direction seems opposite to the broad channel (it looks like it has been running up the mound slope before running down the other side), so that's not the source. Actually there is no source the way I see it, there's just this channel looking like it has been carved into the mound and I can't see water, mud or lava creating these features.
These features plus the ones from the first post makes me doubt that the channels were carved by water/lava, they seem to defy gravity and are running across and through upraised areas without normal tributaries, sometimes running towards nothing and sometimes starting from nothing (even into the side of a crater, imo).
I'm puzzled to what might have caused these channels if not water action or lava flows.

Cheers.

lswinford
2004-Aug-11, 06:47 PM
I think I see what you mean. We still run across the problem of apparent vs. actual levels. But some of the matter could be the result of changes over time as representative of different time periods or event epochs. Take the common story of the American Grand Canyon in northern Arizona. The meandering stream bed was originally set on a mature flood plain. There was an uplift, increasing the flow, increasing the erosion, and the meanders supposedly cut increasingly deeper channels, especially as so spectacularly displayed on the Green River tributary upstream in Utah. In your picture, there was one period when flows (lava, water, mud, who-knows-what fluid flow) were carved. The event conditions changed, fixing the landscape for a time, and when another event developed, the fluids came from another direction or source and meanwhile the geographic 'level' had changed. Like the Olympus Mons story, the floor sank when the magma zone below collapsed. If it did not sink evenly or uniformly, there could be differing gradients for later fluids to flow down--and different streambed directions.

Aw, heck, when I travel the highways of my town, seeing how straight lines tend not to be very straight for very long, maybe Martians were digging irrigation canals and they had the same problem as my local street surveyors of years past--where we often ask the question, "Were they sober when they did that?" :D

VanderL
2004-Aug-12, 06:45 PM
Hi Iswinford,

I see what you mean; some carving then some lifting, some more carving and some tilting and then some carving again. That could be true when different processes are continually (re)shaping the landscape. Just like this fractured crater, the Grand Canyon needs this explanation to be formed by known geological processes, but unfortunately we can't spool back the film of how the Grand Canyon evolved, so we will never be sure that's how it happened. A feature that is seen in both the Valles Marineris (the Grandest Canyon in the solar system) on Mars and the one over here are the extremely short and deep (steep) side-canyons (tributaries). They seem totally different from other tributaries that we see in most river systems.
The features in the crater of this topic all seem to have formed the same way, whatever that "way" is. What puzzles me is the lack of clear sources for any water/lava to have flowed, and the lack of basins that the material ran into, filling it with the debris/mud. Where do all these "rivers" go, around in circles?

Cheers.

Duane
2004-Aug-12, 07:21 PM
Where do all these "rivers" go, around in circles?

How about they pool, then evaporate? Seems to be the finding at Merdiani Planum, where Opportunity is.

VanderL
2004-Aug-12, 09:34 PM
Where do all these "rivers" go, around in circles?


How about they pool, then evaporate? Seems to be the finding at Merdiani Planum, where Opportunity is.



Where are the pools/basins in the "fractured crater" and where did they start from, where is the supply?
And what about these ultrashort "tributaries"? And where is the debris gone?
And wht about these features (http://www.thunderbolts.info/tpod-archive-04/tpod-etched-mars.htm) isn't there any chance at all that maybe something out of the ordinary did happen?

Cheers.

Duane
2004-Aug-13, 04:21 AM
Where are the pools/basins in the "fractured crater" and where did they start from, where is the supply?


From what I can see, without relief, is to the far south and the west sides of the crater (assuming top as north). I already said that Louis. Further, the flows seem to overflow the crater rim to the south, and then run down the slope.

I already said they start at the crater wall, where the slope has slumped. I suggest this is similar to terrestrial slides, where water penetrates the subsurface soil to loosen the overlying soil, causing it to flow. A mudslide, for lack of a better term. Probably more like a lahar, if you are comparing it to terrestrial features.

They come from frozen briney water trapped in the walls of the caldera. I said this previously too, in a discussion VanderL and I were having way back in January.


And what about these ultrashort "tributaries"? And where is the debris gone?

Can you not see the sedimentary deposits right below the end of the flow area? Even if that wasn't there, considering the short length of the tributaries, what debris might be dredged up? Can't it be the case that the soil being overrun is also saturated with frozen brine?


And wht about these features isn't there any chance at all that maybe something out of the ordinary did happen?


What, like a lahar? Or a viscous mudflow? Or a lava flow? I wouldn't call any of these out of the ordinary, so I guess my answer is probably no.

Guest
2004-Aug-13, 05:25 PM
Hi Duane,

I'm not convinced by your mudslide suggestion; I still don't see how an angled, horizontal channel can be the source of a downward flow, it should run down, not under an angle to the crater rim. There are no gullies running downward and the frozen briney stuff you mention, shouldn't it form gullies? Normally you expect rivers to be fed by smaller streams, right?
I can see what you call the sediment, but it seems a fraction of what one can expect if there is no real outflow. The overflow you mention in the South is also strange, it must have been flowing upwards over the rim without leaving any trace (again no gullies).
The link I provided shows even better what I mean by empty channels, you call them lavaflows or viscous mudflows, but where is the excavated stuff? Where is the source and where is it going.
And what about the straight broad channels with steep sides, crossing each other. What can possibly make these features? And because there is hardly any dust settled in most of these features, given the large amount of duststorms, they must surely be considered young.


Cheers.

VanderL
2004-Aug-13, 07:04 PM
Forgot to login again, that was me Duane.

Cheers (sigh).

lswinford
2004-Aug-18, 03:26 PM
One of the things that makes me guess at multiple events to derive the current picture is the variety. You have big and obvious channels and smaller, shallower channels, and places around part of the circle that look like pooling or broader, shallow flows.

In any event, I see the pictures, hear the discussion and somehow wonder if a certain writer, telling a tale of some blind men describing an elephant, couldn't be told of we the sighted. In that situation, I am positive that I'm at the tale and just stepped in something. Still, the discussion was a fun exercise, thanks to all.

VanderL
2004-Aug-18, 03:29 PM
Hi Iswinford,

We've been touching the tail of the elephant, here's the trunk! :D

What do you make of this link (http://www.thunderbolts.info/tpod-archive-04/tpod-current.htm).

Cheers.

Duane
2004-Aug-18, 07:36 PM
I have seen the link, and call **. This is the original THEMIS image:

http://themis.asu.edu/fullimages/20040225A.gif as released by NASA Feb 25, 2004. It also seems to me VanderL, that we have discussed this exact image previously during another attempt you made to suggest this is an example of a lightning discharge.

Again, VanderL, this is a THermal EMission Imaging System (THEMIS) image that has not been calibrated and has been altered by the imaging team to apply an empirical correction to the original image to remve camera defects.

I have said this before, there is no relief by which to judge the size of this feature! Further, there is nothing by which to identify the location of this feature on a martian atlas.

The writers comments in your link that the craters are somehow new or associated with the rille are misleading and without substance. The suggestion that the beginning of the rilles begin with "a rounded crater" are misleading and without substance.

The image is made up of thermal energy--you cannot suggest that anything is "rounded" or " edged" because you are looking at differences in temperature.

As I said at the beginning, I call **!!!

Guest
2004-Aug-18, 09:10 PM
What exactly do you mean by "I call **", remember English is not my native language.
As to the picture above, this image might not be calibrated but it does show the features that are described in the link.


I have said this before, there is no relief by which to judge the size of this feature! Further, there is nothing by which to identify the location of this feature on a martian atlas.

So what do you think this image shows, after all it was posted by the THEMIS team, and if you look in the rille floor you can see the familiar small ridges/sand dunes.


The writers comments in your link that the craters are somehow new or associated with the rille are misleading and without substance. The suggestion that the beginning of the rilles begin with "a rounded crater" are misleading and without substance.

You mean that you don't see the craters, or what?

Do these craters represent something else as well because of the uncalibrated thermal nature of the image? It could very well be that this is an image we discussed before, but I must have taken it from the Spaceref website that always have an Mars "Image of the Day".

Would an image from a normal camera of the same region help?
I'll try to find out where this image is from, maybe we can get to an image that is "up to standards".

Cheers.

VanderL
2004-Aug-19, 11:37 AM
Hi Duane,

The guest was me of course on the wrong computer again. I checked, but the THEMIS image we discussed earlier was different from this one, but I have yet to see a THEMIS image that shows a totally different image from "normal" imaging. The temperature profile follows the contours of the surface, plus extra information, which is mostly subtle (and sometimes shown in false color). Certainly not different enough to warrant BullS### (if I read that statement correctly, that is).

Cheers.

Duane
2004-Aug-19, 04:04 PM
Thats ok VanderL, I knew it was you because of your signature :)

As to the image, or more precisely the story that was attached to it, yes you understand the term ** as I intended it. The author of that fiction is using an image that has a passing resemblance to "real color" images from a camera like that on MGS to outline a number of assumptions. The assumptions he/she arrives at are complete ** because the image has no reference points, no scale, and no description from the imaging team to explain what you are looking at.

The author describes "rounded" features in the image that may or may not be there. You can't tell from just looking at the image VanderL, because a thermal image does not show contours well. The "roundedness" spoken to by the author is probably an artifact of the temperature gradient between the flat plains and the floor and walls of the rille. The thermal image makes it look rounded when it probably is not.

Furthermore, where was the sun when was this image taken? Noon? Evening? On the other side of the planet?


So what do you think this image shows, after all it was posted by the THEMIS team, and if you look in the rille floor you can see the familiar small ridges/sand dunes.

I think this image was released because it looks artistic in the minds of the imaging team. Nothing more. Maybe those are dunes/ridges, or maybe they are the result of tiny differences in temperature, or maybe both. My point is, you can't tell just by looking at the image.


You mean that you don't see the craters, or what?


No, I mean the article's author attempts to extrapolate some fantastic scenerio for the crater-like formations based purely on their appearance. As I have said, the image is made by using small differences in temperature. The features probably appear "rounded" because of different temperatures on the plains as opposed to the floor and the walls of the features. We don't know, because we are not given enough information by which to make an accurate judgement.


Would an image from a normal camera of the same region help?

Yes, as would knowing the time of day this thermal image was captured.


but I have yet to see a THEMIS image that shows a totally different image from "normal" imaging.

They are all different VanderL, because they are made differently.

And yes, the use of an uncalibrated, unexplained thermal image by the author of that article to suggest its use as an example of some extraordinary event is enough to call **.

VanderL
2004-Aug-19, 04:27 PM
And yes, the use of an uncalibrated, unexplained thermal image by the author of that article to suggest its use as an example of some extraordinary event is enough to call **.

Even if he is right? :D

I see your point, and it can easily be resolved if other images of the region show similar features. I'll try to find some. I've also seen similar features in pictures of the Moon, so I hope it isn't too hard to find them. Anyway, just supposing these images are showing true features on a scale that is usual for THEMIS pictures (quite detailed), what do you suggest created the features?

Cheers.

Duane
2004-Aug-19, 05:34 PM
Wow that was fast L :)

I think they are better explained by a flowing liquid of some kind. It really depends on where it is and its size.

VanderL
2004-Aug-19, 08:47 PM
Hi D,

And if I didn't have visitors the past few hours I would have answered already.
Meantime I found the original picture you posted too, plus some close neighbours (not THEMIS, but Malin's stuff).
Water, right? Hmmm, would that have been flowing water, for the life of me I can't imagine how water could create these features. If I think about rivers and streams there's always a bunch of thin small streams feeding into a larger stream until one large stream has been formed which divides into a delta before ending up flowing into a basin. Some variations are possible (streams disappearing underground)
Well, I also asked the THEMIS people if there is more info on this picture and hopefully they will respond. If not, the only thing I can imagine right now is posting the links to pictures of the "close neighbours" and speculate about what they show. I think I'll wait for an answer and try other options later.

Cheers.

lswinford
2004-Aug-20, 04:11 PM
VanderL, it was an interesting observation. I think it was a line in a Woody Allen movie, Sleeper if I recall correctly, where some doctor was smoking and Allen's character mentions that they used to say that smoking was bad for us. The doctor smiles and says something like, "We've discovered that a lot of things we thought were true are not." One of the things I've enjoyed about the iron core sun discussion on Oliver Manuel's ideas was that some things are not exactly fitting into the common picture. I love it when things don't exactly fit. Thanks.

Duane
2004-Aug-20, 07:07 PM
Even if he is right?

Yes, even if he is right.


Hmmm, would that have been flowing water,

Good question VanderL. Seems like the most obvious explanation, without knowing where this feature is or how big it is.

Further, there may be small streams that are not apparent to the camera at this resolution, which flow into the beginnings of the "stream heads". Or they may start on hillsides that are again, not apparent to the thermal imaging used by this camera. Or they might be springs--we see those popping up all over this planet.


If I think about rivers and streams there's always a bunch of thin small streams feeding into a larger stream until one large stream has been formed which divides into a delta before ending up flowing into a basin. Some variations are possible (streams disappearing underground)


Well, except in those cases where there is a sudden catastrophic release. Such as a volcanic eruption like we see in the Cascades in the western US (Mt St Helens for example).

VanderL
2004-Aug-20, 11:15 PM
Well, except in those cases where there is a sudden catastrophic release. Such as a volcanic eruption like we see in the Cascades in the western US (Mt St Helens for example).

We need a lot of catastrophes to account for all the features on Mars, there are to my knowledge no clear "streams-river-delta-basin" examples to be found. There is evidence of water on Mars, but no evidence of flowing water in sizeable quantities. Why not keep it simple and assume Mars was Earth-like once and catastrophically changed (only once) to the Mars we see now?

Cheers.

VanderL
2004-Aug-21, 09:38 PM
Well, I also asked the THEMIS people if there is more info on this picture and hopefully they will respond. If not, the only thing I can imagine right now is posting the links to pictures of the "close neighbours" and speculate about what they show. I think I'll wait for an answer and try other options later.

Funny to use your own text as a quote, is that the same as talking to yourself? :huh:

No answer to my mailed questions, so I think I'll just post some of the "nearest neighbours".
This image (http://mars.jpl.nasa.gov/mgs/msss/camera/images/E01_E06_sampler2002/nirgal/index.html) and this image too (http://www.msss.com/mars_images/moc/top102_Dec98_rel/valley/n_24106_sub50perc.gif) are close but no cigar (note the high amount of cratering near the channels).
I think that the image I linked to earlier and Duane posted as well is located south of Valles Marineris. On the larger overviews you can see a lot of side canyons connecting to the main chasm, and all of them have these deep short tributaries. Close-ups of those tributaries can be expected to show the "rille" feature I'm ranting about.
This infrared image (http://themis.asu.edu/zoom-20040625A.html) shows some features that look like the "fractured crater" image, espcially the bottom part shows the "tilted" river and some very strange craters.

Cheers.

VanderL
2004-Aug-28, 09:00 PM
Hi Duane,

I received a reply by the THEMIS people that says that the image is 22 by 22 km and that the "THEMIS as Art" series was used to pique the interest of the audience to visit the website and search the picture database. Unfortunately he/she didn&#39;t mention where on Mars the image was taken. The only hint was that if I searched long enough I was sure to find it. <_<
I hate that, I tried to find the image in their database and I was struck by many very detailed images of very uninteresting sites. The clickable map (http://themis-data.asu.edu/mars-bin/mars_cgi_map.pl?DISP_DATASET=Vis+%26+IR) shows where the images were taken. I wonder what the reasons were for excluding some very interesting features.
The search continues.

Btw do you want to comment on the images in my previous post?

Cheers.

VanderL
2004-Aug-31, 12:45 PM
Hi Duane (helloohoo, anybody out there??) :D

Here (http://marsprogram.jpl.nasa.gov/mgs/msss/camera/images/E01_E06_sampler2002/nirgal/) is probably a picture of the region we discussed earlier, Nirgal Vallis. It has the scalloped wall-features, the dunes on the bottom of the channels are clearly visible, and in the accompanying text the strange notion that the dunes are old is discussed.
One other thing about Nirgal Vallis, from the overview image it looks like a real river, but close-up the picture changes, the channels are too short and too wide (and too deep imo) to be a "water" river. And if you look at the place where the Vallis ends (conects to another larger stream-feature, which is not visible in this image) the bottom of the channel is actually rising and narrowing (so no sudden flow-discharge can explain it). What do you think, is the THEMIS picture taken from the Nirgal Vallis, and if so, when you compare it to this image don&#39;t you agree that the features are very strange?

Cheers.

lswinford
2004-Sep-02, 08:21 PM
VanderL, thanks for the link. That dune picture was fascinating. One thing that has me puzzled are the clear circles, said to be impact craters preserved. But there are no shock distortions, or in one case they are very small. Take the main arch, with its three upward branches, the circle opposite the junction of branches 2 and 3 to that arch, are on the slope of this main dune body. It obviously is not simply the loose sand dunes we see on earth, but merely resemble for that hole punched in the side of any earth dune would fan sand out and away and disturb the body to fill in the hole, perhaps with a dimple, such as the depression in the spil-out zone below and a little to the right of the circle in question.

The circle between the upward branches 1 and 2 show something more expected. There are the ejecta streaks radiating outward and there are the clapsing sand bulges falling toward the crater. The lack of such in the lower-right hand third of the circle, I would guess, indicate something to the direction of the object&#39;s fall, with sand sloughing in the upper left in direction of the object&#39;s momentum.

Still, those flat tops are almost as strange as that first circle I mentioned. That just looks weird. Thanks for the picture.

VanderL
2004-Sep-02, 09:07 PM
Hi Iswinford,

I&#39;ve been browsing the database on the pictures from Mars and there are many very strange features. The picture I linked to above is in my opinion a complete riddle, just try to imagine what the wind has to do to form the ridges on the valley floor (blow at right angles without disturbing the pattern?). That would exclude wind as the origin of these "hatched" features. Water can&#39;t have created the valleys themselves, just try to imagine where the water came from and where it supposedly went. Whatever formed the channels/valleys and sculpted these features it is not any of the common erosional forces (water, wind or lava). Faulting and rifting is also out of the question, so whatever created these features? And you&#39;re right, are these really impact craters or can thy be something different.

I say we need a good look at the possibility of giant discharges creating these and other features.

Cheers.

Duane
2004-Sep-03, 12:05 AM
Here&#39;s an interesting false color view VanderL. What do you make of it?


http://www.solarviews.com/browse/earth/saltglacier.jpg

VanderL
2004-Sep-03, 06:58 AM
A nice mess&#33; My guess is that it is not Mars.

Cheers.

suntrack2
2004-Sep-04, 03:57 PM
well Sir,
this is the nice photograph it seem of a mountain or mountain near the valley, and some print of palm like design is looking on the far left upper side of the image, what is that? the colour is very nice,orange like, stone looking in a special shape with neat slopes,



sunil

suntrack2
2004-Sep-04, 04:03 PM
the interesting image looking in my opinion is a water gathered nearby the stones on the beach of a sea, the view has been taken very closely, and i cannot guess more.


sunil

Guest
2004-Sep-06, 10:50 PM
Hi Duane,

Been on a very nice long weekend (gee, I got a sunburn and I didn&#39;t even leave the country) and I just remembered the image you posted.
First, I found the source (you shouldn&#39;t have told me how to post web-images, hehe) and second, what on Earth (pun intended) does an image of a "salt glacier" have to do with Nirgal Valles? And third, if you are suggesting that salt glaciers exist on Mars, there must have been big oceans, right?

Oh, and did you consider the "problems" I outlined in explaining the Nirgal Valles?

Cheers.

lswinford
2004-Sep-07, 01:27 PM
Fascinating picture Duane. I&#39;m secretly betting with VanderL that its not Mars.

If the three darker brown mountains were volcanically uplifted, and the two black rock areas volcanic flows, then the saw-tooth boundaries of the brown mountains are where the previously intervening layer broke for those mountain intrusions. Suppose the flow channels are from condensing steam of the volcanic flows? Juvenile water sometimes congregates to appreciable amounts in earth&#39;s vulcanism.

I just wonder if we are thinking the wrong thing about appearances of Martian water flows. If we are assuming a primarily atmospheric water cycle instead of a volcanic, ground-based water cycle. Steam and liquid water is in the warmer ignious zones and sometimes is forced up by internal pressures (magma upwellings or steam pressures), and it is this incidental water that we have evidence of, not atmospherically-generated rivers and seas. Then too, with the low pressure atmosphere, water that didn&#39;t simply sink back into the porus sands boiled off, and the ice caps then are its eventual precipitate.

VanderL
2004-Sep-10, 09:50 AM
Hi Iswinford,

What are you betting?
You will win, because the image Duane posted can be trace (ask the image&#39;s source and copy this into the location bar)
Eh, DDuane are you planning on answering our questions?
I think you&#39;re partly right Iswinford, but even frozen water masses "catastrophically" released won&#39;t do the trich in most instances, imo,

Cheers.