Oh god, I can see Certain People claiming these are martian stromatolites or vegetation or something, and were deliberately airbrushed out of photos taken later...

Three frame stitch:

http://paranoid.dechengst.nl/mars/are%20we...apa%20smurf.jpg (500 KB)

Looks like we'll need HDR imaging to get good results overall.

Yeah that overexposed stuff is from sol 1562 (seven sols ago). A few images came down from sol 1569, but all sky. Looks like we need to be patient.

P.S. Thanks for the comments on the QTVR. All I actually did was was export the frames from MMB and load the .pts file into PTGui. Whole process took a few minutes. Okay, I adjusted the image brightnesses first, which took a little longer.

I have great expectations.

Sol Seq.Ver ETH ESF EDN EFF ERP Tot Description
----- -------- --- --- --- --- --- ---- -----------
01570 p2265.06 40 40 0 0 2 82 pancam_cape_verde_10pts_L257R2

One of the first closeup pancams, from sol 1570:
http://qt.exploratorium.edu/mars/opportuni...B0P2265L2M1.JPG
Lot's more to come!

I truly suck at color correction™:

http://paranoid.dechengst.nl/mars/Cape%20V...ee%20frames.jpg (570 KB)

Rockhounds... prepare to go "Oooooooooooooooooohhhhhhhhhh!!!"

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Nice contrast at ~14:40 LTST

Best I can do... others will do waay better, I know

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... and I don't know about anyone else, but I'd be a bit worried about Oppy driving underneath something that looks this unstable...

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Looking at that image I expect a coyote to come plumetting down on the rover and then an anvil to crash down on both of them.

Yes...it is never safe to underestimate the reach of the evil Acme Corporation and its fiendishly persistent (though clumsy) field representatives...

Good point, though. I have no clue how stable these cliffs are. Come to that, we really don't have much of a clue as to the frequency & intensity of martian seismic events, though IIRC V2 didn't find much at all (V1's seismometer was inop, unless I got that backwards). The motion of Oppy shouldn't be enough to trigger anything by itself, though considering such effects in 0.38g combined with an utterly dry outcrop is kind of difficult...are ancient evaporites all that's holding this thing together besides compression?

Although, you do have to admit that Acme has a very consistent track record -- and that record is, to be frank, abysmal. Therefore, you'd expect the Acme Mars Lander Wile E. Coyote would have to have used would not have gotten Canis Coyotus safely to the surface, much less anywhere near our beloved Oppy...



-the other Doug

I was slightly disappointed yesterday, but I have greater expectations today.

Sol Seq.Ver ETH ESF EDN EFF ERP Tot Description
----- -------- --- --- --- --- --- ---- -----------
01571 p2266.06 80 80 0 0 2 162 pancam_cape_verde_20pts_L257R2

Oh my...

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... and a couple more views before I head out to work... looking forward to seeing everyone else's efforts when I get back

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Not much of tosols bit has come down, but most of yestersols has.



(Click image)

James

I am really impressed by both stu's and james canvin's views of the strata exposed on the face of Capo Verde. For the first time details can be seen in the shadows. Now the geologists can get to work describing these beds which I think are stratigraphically below the Gibson band that Oppy RATed a few months ago. Am I correct in thinking that I can see lenticular bedding or am I just imagining it? Am I correct in thinking that some of the rocks on the slope are in situ and are therefore representative of an even lower stratum?

I always think of the Acme Corporation when I see the Maas joke video of the RAT going into the rock and the rover spinning around. "If the Acme Corporation had developed the MERs."

Has there been any attempt to correlate the layers in Victoria to the layers identified in Eagle and Endurance craters? Was there any effort to follow the sequence(s) and surface layers with the APXS and Mossbauer data as Opportunity moved South? As I recall there was some ratting and integrating underfoot throughout the trip and in the exposures in Erebus.

Opportunity's little Mossbauer unit must be pretty tired by now. It has a halflife of 3/4 year (roughly). So now, after about 8 half-lives, activity is down to a few parts per thousand of the initial strength.

There is a path in front of the rover which has a rocky ground almost at the base of the wall. That ground is layered, visible on both nav and pancams, and might be in situ.
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Hot off the press...

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... and 3D view...

... and a bit of the floor, too... lots of rocks Oppy, be careful now...

We have GOT to get a closer look at the jagged rock bottom left on this image...

Definitely one of my favourite post-entry views...

Today's offering.



James

Another sol, another spectacular set of pancams - here's one of my favourite views, in 3D:
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My favourite views:

http://qt.exploratorium.edu/mars/opportuni...B0P2266L2M1.JPG
http://qt.exploratorium.edu/mars/opportuni...B0P2266R2M1.JPG

Looks like frames from old science fiction movie (Star Trek).
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Just one image short of completing the sol 1570/1 bit now. It's becoming an amazing view!

Still this is only half of the total pan taken so far if you include those from sols 1572/3 that are still on the rover.



James

Superb mosaic, James, even with dirt and unfilled rectangle...

Edit: Here I tried to reduce effects of dirt and glare in the half res version:

The discontinuity between the thick central unit and the lower unit is interesting. Those lower layers seem to be at a significantly different orientation than in the upper.

Very interesting observation! Anyone got a possible explanation?

Mmm...differential weathering? I've seen apparent discontinuities like this in the past on Earth; maybe the prevailing wind path around the two vertically separated regions is just different enough to cause the disparity. (I'm assuming that the whole formation is old, old, old...)

I'm wondering if we are seeing deposition, tilting of strata, erosion of upper section of tilted strata, then redeposition of upper layers of strata.

That would imply the lower layers are old, AND had an interesting history prior to the deposition of the upper strata.

-Mike

No - much more likely to be just cross-bedding - i.e. cemented dune sandstones.

Phil

I thought cross bedding had little "wedgie" shapes?

At first glance it looks like truncated cross-beds or an unconformity, which is consistent with the aeolian dune-playa setting. We've seen this at several places in Endurance and Victoria. But if you look closely at the lower beds, you can see a fabric of essentially horizontal beds, morte or less parallel to the upper beds. So I'm thinking that one or the other orientation of the lower bed may be an artifact of aeolian erosion. We need an up-close look. We'll also be able to tell more once Oppy starts taking images out of the flat (shadowed) light.

Of more interest is the open fracture in the upper beds. Is it a solution cavity, or what?

Another example of the x-bedding is in 1P259578369EFF8900P2570L6M1.

--Bill

Ultimately, these questions all hearken back to the formation of the cape-and-bay crater rim. Why are the bays eroded down the strata at a 20 - 30 degree angle, while the capes are cut down more or less vertically. I can't believe that this is due to a more resistant sediment formation in the capes, neatly interspersed with less resistant strata in the bays. Until somebody lays out a plausible hypothesis for the formation of Victoria's sinuous rim, I don't think this little microcosmic curiosity at the base of one cape can be understood.

Primarily: Capes have greater exposure to the prominent erosion forces - prevailing winds. As a result they are in a less stable vertical condition. The bays are set back and more sheltered from the prevailing winds so they are older and have had time to slump. As an example go dig some holes in your yard, one each month. After a year see what the sides of the holes are like. The newest holes will have the steepest sides, the older holes will have slumped in on themselves.

Secondarily: The capes by virtue of their recessed shape are traps for the heavier particles that the winds are unable to lift from the crater.

This back and forth of capes and bays likely occurs in a manner analogous to a meandering stream. Over the eons the shapes will migrate back and forth as bays fill up and capes are eroded away...and the crater grows ever larger (assuming some external condition doesn't cause it to become filled in by migrating sand dunes or such.)

The problem with this argument if I understand it correctly is that the capes consist of ancient undisturbed strata and not the recent deposits you would see on the bank of a river. I think that the argument only works if Victoria crater is getting bigger at the same sort of rate that the capes are moving. Then there would always be a supply of fresh undisturbed strata from which to carve out the new capes.

Agreed, but I've not been able to wrap my brain around a plausible mechanism to explain the "scalloped" rim around Victoria (et al). With a couple of prevailing wind directions, there shouldn't be such symmetry in the scallops. I'm sure that the explanation is as simple as the ones covering stream meanders or salients and recesses, but I've not stumbled upon it.

--Bill

Concerning cracks and weathering around Victoria's rim, I wonder what effect the shock from the impact that caused the crater has. The blast must have left a pattern of disruption and cracks radiating for some distance that had an effect on future weathering.

My amateurish observation is that there is a broad lower band (just above the talus deposits) where the stratification is quite noticeable while on the band above that, the stratification is much less distinct. I'm assuming the whole wall were looking at was exposed simultaneously with the formation of the crater (or sometime thereafter). Two possibilities come to mind:

1. The level with marked stratification is made up of alternating strata of differing physical or chemical composition, and so the strata are eroded much differently which makes their differences strikingly visible.

2. The level with marked stratification has broader strata -- i.e., they were laid down in response to slower changes -- and so the erosion is more noticeable.

Comments from the experts are welcome.

Steve M

It's not true that the deposits on the banks of a river are necessarily recent. Rivers cut through some very, very old layers just as the wind on Mars is doing. Take a trip to the bottom of the Grand Canyon. There are entire banks in places made of Vishnu Schist which is 1.7 billion years old. The same is true the world over. In fact the best way to locate old layers is to examine the banks of a river (when there is no convenient road-cut nearby.)

Certainly radial fractures could create the seeds of an erosion pattern that might evolve into the resulting symmetry we still see after so many eons.

The question of whether the pattern of the crater wall is due to the radial fractures produced by the impact or whether its because of other factors depends, I think, on the frequency of occurence of such craters with such exhibiting such a pattern.

If this 'Victorian spikes' design is particularly unusual for the region and we assume uniformity in the nature of the sedimentary rocks, one could be tempted to conclude that the impact is responsible for the pattern.

Another reason is because of a combination of the impact and nature of the rocks factors?

Is there another crater with such a pattern nearby?

From the abstract of a recent article discussing Victoria crater (see Nature of Victoria's Dark Streaks thread, post 430):
"...sand [in Victoria Crater] is supplied from outside the crater and is presently escaping it's topographic trap. This process presents a possible explanation for the serrated margin of Victoria crater, through abrasion of the soft rock as trapped sands are blown out of the crater and carve alcoves under various seasonal winds."


What causes the regular spacing of the scallops? Good question. It could be from radial fractures from the crater formation (as centsworth II suggested), or it could be initiated from subtle turbulence effects as sand carrying winds swirl around the interior rim of the crater. It'd be neat to watch it evolve over time (a geologically long time, I reckon).

-Mike

Why is the rim shape so rare on Mars? Sand and wind and craters are everywhere; I'd wager the cape and bay shape is less than one in ten thousand.

I've seen other examples in HiRISE images of scalloped craters, I ought to dig through and catalog similar crater-forms. Ugh.

At one time I speculated that the radial scalloped rim was due to the Anatolia Features, which were originally seen near Eagle-Endurance craters and are presumably concealed under the dune-sand south of the type area, and have been noted near the southeast rim of Victoria.

Attached is an image showing the trends of the Anatolia Features and also the trends of Victoria's scalloped rim (I don't recall if it's mine, I might have purloined that Victoria image from a post). You can see similarities, but you'd need to run stats on the trends to make sense.

Presented FWIW.

---Bill