The first pano I've made with the flatfiel I've created. Needs some adjustments during the processing. Frame per frame, different opacity level if it's a L2 picture or a L7. But it seems to work in the final result .
Non definitive pic. It miss a lot of data as you seeing it.
I remarked that stitching is harder with this dust deposition

Agreed, it's a cool story. However, I'm not sure if it's true. The observed vugs are extremely elongated. Many, many minerals can grow with elongated habits; meridianiite (low temperature hydrated Mg-sulfate) might well be one of them, I don't know. I can, however see a different problem with the elongated vugs representing former Mg-sulfate crystals. The rock matrix, at least where the vugs were first seen, is allegedly rich in Mg-sulfate too (up to 30%). Logically, I can't see why Mg-sulfate crystals would preferentially leach out of a rock that itself is rich in Mg-sulfate - sort of like asking certain calcite crystals to leach preferentially from limestone or marble, or certain salt (halite) crystals to leach from a bed of rock salt. Where you see crystal-shaped cavities (molds), the mineral involved was typically much more soluble than its matrix (e.g., elongated gypsum-shaped molds in sandstone), or chemically unstable with regard to its matrix (e.g., cube-shaped molds in vein quartz that indicate the former presence of the iron sulfite pyrite, since weathered away). While it's possible that there were elongated crystals of meridianiite, the more hydrated form of Mg-sulfate, in a matrix of the less hydrated form, and that they became unstable on heating to just above their breakdown temperature, just above freezing, I don't find this likely over a large area or volume. It further reflects the "vaguely possible if everything went just right, but disturbingly improbable" aspect of many proposals regarding Meridiani and liquid water, IMHO. I find it much easier to hypothesize that the vugs represent a more soluble and easily leachable former chloride mineral (or some other diagenetic phase other than Mg-sulfate). Of course, cold temperatures, ice, and Mg-sulfates all seem to be common on Mars, so meridianiite could likewise be common. I'm just not sure if it explains the crystal molds.

For comparison, the photo below shows elongated vugs presumably representing former crystals of gypsum, a slightly soluble evaporitic sulfate mineral, in a matrix of pure quartz sandstone:



I took this photo in May, 2003 (well before the Mars rover landings) on a Grand Canyon rafting trip (outcrops just above Deer Creek Falls at Mile 136.3). With my boot for scale, it shows rare crystal molds in the Tapeats Sandstone, interpreted as a 540 million year old beach sand deposit. In this case, some seawater presumably became locally isolated and partly evaporated enough to precipitate gypsum or some other salt, then sand was washed or blew in around the crystals, and then the sand deposit was hardened into rock (by carbonate cementation of the sand grains). The salt crystals dissolved in groundwater at some later time, leaving crystal molds in the sandstone. A similar near-shore evaporitic or sabkha environment was initially deduced for the crystal molds at Meridiani, but has since been modified (to wind-blown sulfate "mudball grains" from a dried up and vanished acid playa lake later soaked in rising and falling, evaporating and flowing brine, if I understand the highly complex proposed scenario correctly).

Regarding the much smaller size of the Victoria Crater "turkey tracks" as compared with those molds initially imaged in Eagle Crater, I wouldn't attach too much significance to this observation. It presumably indicates that whatever conditions favored crystal growth didn't last as long (or were otherwise less favorable) at Victoria. Other than size, the crystal molds look pretty similar. Although they also resemble the elongated crystal molds in my Grand Canyon photo above, logically they can't represent former gypsum, because gypsum is much less soluble than the Mg-sulfates found in the Meridianii matrix. I have no comment on the degree of degradation - even the original vugs in Eagle look pretty degraded to me.

-- HDP Don

A bit off topic (okay, a LOT off topic)...but Don, I think the structures in your picture are the bottoms of the U-shaped burrow Diplocraterion, which are common in both the Tapeats and Bright Angel...

If the structures from Victoria are the the bottoms of U-shaped burrows (and I do NOT think that they are!) then, yowza, we've got a paper to write...
--
Tim Demko

Thanks for all the pans, guys. There was something about that sol 1294 view that looked oddly familiar, and I think I've got it. Compare this pancam view from sol 1294 with this view from the distant past.

Ah, isn't it wonderful that we can look back with nostalgia at images from a mission that's still going?

Hi Tim - Thanks. You might well be right (your specialty, not mine), plus it's been over 4 years since I took the photo, and I've never this particular feature anywhere else in the Canyon. Many exposures of the upper Tapeats, Bright Angel, and Muav are chock full of lovely burrows, I agree, and I've taken hundreds of great photos of typical burrows during several Canyon rafting trips, including during my trip last summer. As I recall, this feature was restricted to a single bedding surface in relatively coarse sandstone, there were no burrows evident elsewhere in the rock (i.e., as seen in section), plus especially some of the elongated cavities appeared to have planar crystal terminations (including one easily seen just above and to the left of my boot-tip in the photo). That, plus the inferred supratidal to subtidal environment, was my basis for inferring that these could represent the exception, traces of inorganic crystals rather than of organic burrows. Still, Mars is far from the only place where digital images can show you just what you're looking for, and if you have a mineral named after you, you're probably looking for crystals. So, probably, guilty as charged, and thanks again.

Occam's Razor would certainly suggest that if you're in a group of rocks that is well known for its burrows, any enigmatic linear cavities that you see just might be related to burrowing, rather than to what you had assumed or hoped they would be (crystal dissolution). By the same token, low pressure, icy Mars is well known to be more than saturated with impact craters, presumably related to the Late Heavy Bombardment, plus numerous later impact events, so might not enigmatic layered, cross-bedded, salty rocks at both rover sites and elsewhere be related to ice and impact cratering rather than to what you had assumed or hoped they would be (warm flowing and standing liquid water, or warm liquid water interacting with hot molten rock)? Well, we've already had that liquid water discussion here, and although Oppy is now in Victoria Crater and Spirit is back on top of Home Plate, little appears to have changed, least of all anyone's opinion.

BTW, I just now looked up Hereford's 1977 article on the Tapeats depositional environment in the Geological Society of America Bulletin (vol. 88, p. 199-211), and he referred to the U-shaped burrows as Corophioides. I presume someone has since changed the name? In any case, Occam's Razor strongly suggests no such burrowers at Meridiani. Too bad. We'll have to write our first joint paper on a less exciting topic.

--HDP Don

Cold fusion? Sorry, couldn't resist.

Here is the view inside Victoria Crater taken with the

R0 Navcam on Sol 1313.

jvandriel

Interesting shapes in this one.

Source image: http://qt.exploratorium.edu/mars/opportuni...00P2580R2M1.JPG

Here is the complete view inside Victoria Crater.

Taken on Sol 1313 and Sol 1314 with the Ro Navcam.

Dilo,

stitched with Autostitch and as you can see, no problems.

jvandriel

This surely has been quite an eclectic trip over the edge, as seen through many eyes. Thanks to all of you who commented and posted interesting images. I think I'll toss in some right eye false color images.
I don't think there are a lot of fans of these right pancam IR false color images, but I am always on the alert for new sets of R-all images, and even the occasional R-less-than-all sets. As I mentioned before, they seem to highlight certain mineralogies. Here are the most recent right eye false color images from my point of view. Without a doubt, we are well into the section where hematite spherules have formed.

... and in real(ish) colour...

Hi,

The two mosaic showing crater interior on Sol 1294



Link to other resolutions

Lenses are so dusty. I become to be so nostalgic about pre-storm pictures .

If Opportunity continued to RAT further into the rock, would it find the minerals, still in place that produce these "vugs" ?

My popular science-level geology take:
The conditions that dissolved the crystals happened long ago
-- before Victoria Crater existed -- and dissolved the crystals
in the entire stratum, not just the current surface.

The "blueberries being formed by current surface conditions"
people may have a different take.

Ant, you did a great work!
I started from these pictures to further equalize contrast/luminosity disuniformities, adding a sharpening too:

(artificial sky in first picture).