I agree too, best thing is to focus. But anyway, I'm a bit surprised they didn't even stop for one sample! May be they'll get back up before plunging deaper ?

I have to disagree with Alan -- this is not the first ejecta blanket we've had a chance to study. The first couple of meters down into Endurance were what Squyres called a "dog's breakfast" of jumbled ejecta, and Oppy also skipped down past that until she got down into the intact layered stratigraphy.

The whole point is that intact bedrock tells you a much more complete story than jumbled ejecta. Yes, the science teams *may* take a good look at anything they see in the jumbled ejecta as they exit the crater that looks different or unusual, but even if they do, they'll have no clue from what stratigraphic section anything in the ejecta came. So simply, from a geological standpoint, it makes a lot more sense to study the intact bedrock.

-the other Doug

Ha! A dog's breakfast? I missed that comment. If you could provide a link to that, I would be most appreciative.
I don't really see a lot of value in RATing and analyzing random ejecta blocks, unless of course, we come across something new and completely different. But I do recall a previous comment from Steve Squyres that this would be an opportunity to study a cross section through an impact blanket, so we may eventually see some investigations in the jumbled ejecta. It seems though, that the MER team has expressed more interest in the thin, white layer just below the ejecta.

I find their explanation of the interest in that layer fascinating. Just prior to the ancient impact that formed Victoria Crater, the surface of the light layer was the surface of the land in this area. By studying that surface they hope to learn something about the interactions between that surface and the atmosphere/climate that existed billions of years ago, just prior to the impact. It's probably a bit more complicated than that, but I can imagine it should be an interesting contact to investigate. The whole "bathtub ring" analogy has been overused, but there really are a number of geochemical or diagenetic alteration contacts that we need to watch for. The bathtub rings that have been mentioned in various places are subsurface contacts where groundwater has altered the original rock/sediment. The appearance of concretions/berries embedded within undisturbed bedrock is one bathtub ring that is expected.

I have really been hoping to see the contact between the bright layer and that dark one in detail, too. The color changes and so does the texture of the rock. I can't imagine they would neglect it. From a distance, it resembles the Whatanga contact which was observed in Endurance Crater. That contact is not a stratigraphic contact between two layers deposited at different times. It has been interpreted as a chemical alteration layer associated with the upper, capillary fringe of a paleo-groundwater surface. Here is slinted's color version of that contact from Endurance on sol 310.
Click to view attachment

If they can find any kind of correlation between the rocks found further north and these in Victoria, it will be an important accomplishment.

I don't have a link, but I do have a cite:

"When you look at the Pancam pictures we took from the top of Karatepe a couple of weeks, ago, the upper part of the slope is a jumbled dog's breakfast, made up of blueberry-laden rocks that look like the same stuff we've been seeing for months. A few meters down the slope, though, everything changes. The rock becomes contiguous and regularly banded, the jumble giving way to intact stratigraphy."

Steve Squyres, "Roving Mars," First Edition (hardback), © 2005 Steven W. Squyres. pp.346-347

-the other Doug

I'm really loving this image looking back up, with the tracks through the rim ripple/dune on the horizon.

Nice view of the 'dog's breakfast' as well. The nice layers in front of us do look like a much more tempting target, I can see why we skipped straight down.

James

Yes, that's a great and evocative image jamescanvin!

I must say the dreaded dune on the edge looks wholly unimpressive from here, it barely came above the threads of Oppy's wheels.

And here is the whole panorama.
Click to view attachment
I did a little trick in order to get the whole 360º view. There is a missing image on either the left and right channels so I had to mix one from the right eye on this left eye panorama. I wasn't sure about the results but autostitch is a really amasing piece of software.

What a time for PCTDB to stop updating...

Thanks for the pan, Tesheiner. Looking towards Verde there's a little "shelf" which had been visible from atop Verde. Navcam shows it really nicely in 3D:
Click to view attachment

Attempted to use Autostitch on the latest navcams... lots of layering here...

Click to view attachment

The descent continues...a new SFX image.
Enjoy
Astro0
Click to view attachment

They should use rendered scenes like that as wallpaper backdrops to all their press conferences!

A quick and dirty stitched and colourised view from Opportunity.
What a view!
Enjoy
Astro0
Click to view attachment

Has everyone managed to come up with flat-field corrections for the horribly dusty optics? Or, dare I say it, are these streak-free pancam mosaics indicative of a major cleaning of those optics?

-the other Doug

otherDoug, I just used the navcam pics for the image above and then a little Photoshop trickery to clean it up.
I don't know if others agree though, the navcam pics do look a little cleaner....may be my imagination though
Hopefully others are working on a 'real' fix for the dust problem.
Astro0

I don't think there has been any improvement in the left pancam - same dust model used here.

Sol 1302 two frame L257 'work volume':

Click to view attachment

James

I'm almost growing to like the slightly low-contrast romantic haze the dust has brought to the 'picture'

Doug

Astro0's view of Oppy's current location from Capo Verde seems to show that above and below the white layer are layers which are more resistant to erosion than the white layer. It seems that the undisturbed dune deposits below the white layer and the broken blocks of dune deposits above the white layer stand up to wind erosion much better than the buried "soil" deposits represented by the white layer.

I hope that RAT holes will be drilled in all three layers so that the reasons why the white layer is less resistant than the other two layers will become clear.

Hmm... I'd say just the opposite, Paul. I see the white layer forming a small ledge where Oppy is currently looking at it. The only way a rock layer can form a ledge is if it is *more* resistant to erosion than the layer below it.

-the other Doug

Here is the complete view.

Opportunity looking back.

Panoramic view taken with the R0 Navcam on Sol 1298.

jvandriel

Click to view attachment

I see festoons in the "work volume." They are most evident in the top pancam. I wonder if Opportunity will find itself pretty much at the same stratigraphic level as at Endurance and Erebus.

I politely disagree, so far. Looking at that photo (from post 116) I see mainly bedding planes intersecting irregular topography, as viewed from above. Look at the right branch of the Y-shaped notch about 40% down from the top, 60% to the right, for example, or the right side of the large notch cutting the top left. Cross-bedding and minor bedding irregularities (waviness) make it tricky to see what's going on, I agree, but so far no festoon- or trough-type cross beds are evident, to me at least.

-- HDP Don

Doctor Burt: I agree that bedding planes intersecting irregular erosional surfaces can often display deceptive appearances. Hopefully I am not making such a mistake. The features I was referring to are not as convincing as the Erebus nested festoons at the rock called "Overgaard," but they look like troughs to me. I wasn't certain from your described locations which features you were referring to. In my attached image I have yellow arrows pointing to the troughs I think you won't have to squint too hard to see.
Click to view attachment
From the PDT site, I see that this set of images was called "workvolume_column." It's apparently the beginning of the measured stratigraphic column.

My take on it was that 'column' refered to the two frames being one above each other, i.e in one column.

CR - Inasmuch as Overgaard was Knauth's type example of "normal cross-beds and convex/concave rounded surfaces viewed from above mistaken for festoons" (what a beginning geological mapper might call "sub-horizontal contacts V-ing upstream"), we'll probably have to agree to disagree about that example being "convincing" (I was further convinced that Knauth was right after looking at Overgaard in 3D via a stereo imaging set-up called "GEOWALL"). Clearly, all of the "smile-shaped features" in the lower part of the Overgaard rock photo, referred to in the NASA caption that you linked to, are pointing up cracks in the rock (are V-ing upstream, in other words - and sorry if you lack the geological mapping background to understand my jargon) and thus the "smiles" are optical illusions created by the downward-pointing angle of the Pancam. In any case, thanks for posting the attachment with arrows. Your arrows appear to to point to what I referred to in my original post as "bedding irregularities" - waviness without cross-bedding (i.e., no cross-cutting relations as in real "festoons"). Again, feel free to disagree - the images aren't all that great.

I guess the important point is that real trough-shaped cross-beds ("festoons"), as well as wavy bedding surfaces (what your arrows appear to indicate), can occur in either water-flow or surge-flow rocks, so we probably need to find another, less ambiguous, method of testing whether or not liquid water ever sheet-flowed across the salty horizontal surface of Meridiani.

-- HDP Don

James: You may very well be correct about the image set name, but from my point of view I am expecting them to also begin characterizing the local geologic section, or column.

Doctor Burt: As you suggest, I think we should agree to disagree on this, mainly because neither of us wants to rekindle the great debate. If you'd like, we can continue via email. I am actually a serious fan of the impact surge hypothesis as a theoretical concept for early Martian processes. I am just not convinced it fully explains Meridiani observations.

Inasmuch as the V-ing upstream concept is normally introduced in Geol. 101, it is a well embedded concept for me. I've been a geologist for about 35 years. I've studied Overgaard in 3D anaglyphs, and although its surface does have topographic expression, I think one would be hard-pressed to explain Overgaard's train of nested troughs simply as subhorizontal contacts V-ing upstream. I'll attach an anaglyph of Overgaard for others who may want to look at it in 3D.

Admitedly, the recent "work volume" images really aren't the greatest, and the features I am pointing to are not well defined. But I really think there is more going on there than wavy or irregular bedding. I think I see cross-cutting relationships. Let's just see what we see as the exploration unfolds. Some MIs would help. Supposedly the plan is to travel some tens of meters along this contact. We should get a better feel for what the depositional environment was as we extend our explorations laterally.
Click to view attachment

The thing that really freaks me out when looking at these rocks is the realization that I have never seen such mildly altered sedimentary rocks that are so old, let alone from another planet. We all really do need to keep an eye on our blinders.

Oppy moved again tosol (1305). Here is what is in front of us at the new site.



The right side of this image is the same patch of ground as at the top-left of my sol 1302 image, near where CR was pointing to interesting stuff.

James

It looks like this will be the first place to be "sniffed" with the IDD.

In the previous set of pancams it appeared that we might be seeing some patchy occurances of mini-blueberries. These latest pancams show them more convincingly. If so, this would be the top of the hypothetical, blueberry bathtub ring that was expected. The last time we saw this potential geochemical contact was when the berries became very small and eventually disappeared, near or shortly after Erebus, as Opportunity was climbing the section toward "Hell of a View."

The panoramic view taken on Sol 1302

with the R0 Navcam.

jvandriel

Click to view attachment

Another view taken on Sol 1305

with the R0 Navcam.

jvandriel

Click to view attachment

Must be a lot easier to Rat than the "Pot of Gold" back at the base of Columbia Hills
Click to view attachment

Tom - Thanks for the nice anaglyph of Overgaard. When I look at it, I clearly see the topographic irregularities (notches) I referred to in the lower part of the rock - yielding the "smile-shaped features" referred to in the original NASA caption, but only because Pancam views things from 5 feet up (i.e., they are a topographic artifact of the angle of view). Perhaps we agree there. The "nested troughs" area in the upper right part of the rock is a lot trickier because (1) it contains an actual cross-bed (a normal one) rather than simple horizontal planar beds and (2) the edges of some beds are broken off, making bed continuity difficult to follow across notches. Still, the large notch at the far upper right, and the bedding contouring into and around it, is clearly visible, and the other beds likewise can be followed with considerable mental effort. So we continue to agree to disagree.

Regarding your closing comment, "mildly altered" is probably the key phase, especially considering how salty and old these rocks are. To me that very freshness indicates that they have never seen liquid water for any extended period of time, if at all, in contrast to the extant hypothesis of multiple episodes of acid groundwater immersion and even surficial water flow. To my predjudiced eye they look remarkably like some fresh volcanic surge deposits do on Earth, including the very "toothy" or "ashy-looking" edges of the exposed beds (as seen in the excellent panorama of James Canvin's post #127). They sure don't look like any variety of terrestrial sandstone or evaporite I've ever seen (and I think we can agree on that).

Here for your amusement are some actual current ripples in fluvial sand from the Grand Canyon (2003 rafting trip).
Click to view attachment
Probably not directly comparable, because they seem to have formed in an eddy next to the cliff, but certainly not artifacts of the viewing angle (which was from the side, because unlike the Pancam, I can bend down ). BTW, I took that photo in May, 2003, before I had ever even heard of "festoons". I rafted down the Canyon again last July (Knauth organizes trips every year), and looked for similar flow features along the shoreline, but river levels were just too high (twice the normal discharge owing to lots of flash flooding below the dam at Lake Powell). Made for exciting rapids though!

-- HDP Don

Stu,

It appears that Oppy sent a postcard for you :
http://qt.exploratorium.edu/mars/opportuni...JZP2363L5M1.JPG

Nasa release : http://www.jpl.nasa.gov/news/news.cfm?release=2007-109
So Oppy is tilted 25° and has experienced "only" 10% slipage.
Reading back "Roving Mars" they says that, before entering Endurance, they were confortable up to a little more than 30°. Does somebody know if they ever tried more than that and how far they think they can go with the angle of the slope?
Something else that I don't know is : how much they've tried with a position of the rover perpendicular to the slope which seams to me how Oppy's positioned at this time.

PCTDB is back up!

As far as viewing angle, surely that was addressed at Overgaard with the stereo and MI imagery? And I mean quantitatively, not just "to my eyes that looks like..." or whatever.

I've heard little about the "festoons" since we were at Erebus - I recall that the claims were fairly strong at the time that these were ripples due to running water. Does anyone know if the proponents are as strong in their convictions today? I know there's still keen interest to find more such features, perhaps even by returning to Erebus or some such heavily eroded crater after Victoria.

Fredk - As far as I know, the viewing angle was (and must always be) downwards for the Pancam, as for the MI if the camera is arranged perpendicular to a sloping surface that intersects bedding at an angle (in order to maintain focus across the image plane). The only exception would be if it were parked next to a vertical cliff. What the stereo and MI imagery were claimed to show, and what they seemed to show to this admittedly biased geologist (even on CR's anaglyph) disagreed, obviously. CR and I have "agreed to disagree" on this, and let's leave it at that - I don't want this discussion of exciting new Victoria observations to be diverted.

I will point out (soapbox alert!), however, that saying festoon proponents are "strong in their convictions" makes festoonology sound somewhat more like religion than science. As a scientist, I have no convictions (not even criminal ones ). I only make testable hypotheses or tentative interpretations. I'm waiting for Oppy to show us features that look somewhat more like real current ripples, such as those I showed from the Grand Canyon. Here's a larger version of that photo, and I apologize for the quality (it was taken in full shade by this relatively inexperienced - a that time - photographer using an earlier generation digicam with a dirty - river splash - lens). The climbing and trough-cross-bedded nature of the ripples are very clearly visible, especially in the central shaded area, as is the fact that the current was moving from the right to the left (or coming from downstream, indicating a near-shore counter-current eddy). Near-shore eddies with reverse current flow are very common along the Colorado River, and the river boatmen utilize them to make easier landings possible.
Click to view attachment

If Oppy can show me something like that in Victoria, even I might become a believer in current flow (keeping in mind that surge currents apparently can produce similar features ). In the meantime, might we at least agree that "festoons" are a rather slender thread on which to be hanging the entire interpretation of Meridiani surface water flow, especially if they aren't even unique to water flow?

-- HDP Don

A couple of projections from Sol1298 panorama (right NavCam, hand colorization):
vertical: Click to view attachment
pseudo-polar: Click to view attachment
In the latter, note the deep rover tracks on DB dunes, at 11 o'clock...

mmmmm.... Victoria doughnut!

Great panorama, as usual. What I couldn't help noticing in that image was the really ragged (toothed, ripped, torn, ashy-looking, whatever) edges to the right-side bed exposures, as mentioned in my previous reply to CR. Those looked very familiar. For example, compare this Sol 1305 raw image from Oppy:
http://marsrovers.jpl.nasa.gov/gallery/all...00P2374L7M1.JPG
with this Sol 773 image from Spirit, when it was first on top of Home Plate and about to leave:
http://marsrovers.jpl.nasa.gov/gallery/all...DAP2456L6M1.JPG
Rocks with similarly ragged bedding edges were imaged by Spirit on its way back to Home Plate from Low Hill beginning about 9 months later, and are also common in earlier Oppy images. Do these excessively ragged edges simply represent something unique about wind erosion on Mars, or might there might be another explanation? Obviously, I think there might be, but with a sample size of only 2 sites, it's really difficult to generalize.

-- HDP Don

More sols, more data, so longer movie.

Update: Here's a higher resolution QuickTime version.

The view looking to the South on Sol 1294.

Taken with the R1 Pancam.

jvandriel

Click to view attachment

and the view looking to the North on Sol 1294.

Taken with the R1 Pancam.

jvandriel

Click to view attachment

Here is the first real movie of the dive of Opportunity into Victoria Crater.

Seen through the eye of the Front Hazcam on Sol 1291.

jvandriel

Click to view attachment

and here seen through the eye of the Rear Hazcam on Sol 1291.

jvandriel

Click to view attachment

Wow. Take a look at the latest MI images. Are those vugs?

Thats what they look like........... or bird footprints

They do look quite vuggy don't they. Vuggy's a real word, right?

Doug

Vuggy does appear to be a real word:

Well at least in Texas....

From here:

"Carbonate Classification by Vuggy Pore Space"


http://www.beg.utexas.edu/indassoc/rcrl/rc...ublic/vps01.htm