That's part of "MER Images 101" isn't it?

Stu and Phill...
impressive images guys.

Here is a new animation of Tisdale
pancam sol 2688

Click to view attachment

Ding ding ding! We have a winner!

Likely something benign again, like tilt limits or... dragon limits...


-m

Panorama taken by the Navcam on sol 2688. I guess that the crater on the right is Odyssey.

Tilsdale:

Click to view attachment

"Tisdale" again:

Well. there's lots to see here! But I noticed something on top of the Cape as well. Linear markings, apparently slightly raised relative to their surroundings. These look like the polygonal ridge sets referred to as cemented fractures at Gale crater. We've seen features like this on a mini scale ever since Eagle crater (Shark's Tooth at Shoemaker's Patio), but these are macro examples. Worth a look?

Phil

Click to view attachment

One of the best "circulars" of this mission, I think, because it really gives meaning to the climb onto CY, which turned out to be not much of a climb...

That's roughly where CRISM detected the strongest clays signal. Since Oppy hasn't stopped to sniff around yet, I guess they won't take too long before going for the jackpot.

Unloading joints?

Quite possibly, but filled with minerals precipitated out of groundwater.

Phil

On the way to the cemented fractures to the north (if that's what they are and if indeed we're going there), this feature could be looked over, circled here in yellow:

Click to view attachment

Probably just craters, maybe from the same family, or one crater with material sloshed across the middle. Or maybe pits of some other origin?

That's where the Morlocks are waiting...

But, a bit more seriously, are we learning enough about all this geology & sometimes acidic H2O percolation to speculate about possible cave-forming processes yet? Other than lava tubes I mean.

The rocks are sulfates, not carbonates...the acidity of water shouldn't affect dissolution of sulfates.
(Hmmm, maybe I need to think about this one a bit....).

Anyone?

Geeked out and learned stuff:

Heavy metal sulfates have no pH dependence on solubility at low pH (acid conditions). [http://www.geochem.geos.vt.edu/bgep/pubs/9...mica%20acta.pdf]

General info on mineral weathering (pH dependence about halfway through)
http://home.wlu.edu/~kuehns/Geo311/F09/Weathering4.pdf

Fun facts:
The absorption of high notes in seawater is due to MgSO4 in the ocean. Low notes transmit better. (NaCl has no effect)
http://en.wikipedia.org/wiki/Magnesium_sulfate

The highest hydrated magnesium sulfate known, MgSO4*11H2O is thought to have dissolved away and formed the empty vugs seen in Meridiani Planum.
http://en.wikipedia.org/wiki/Meridianiite

A stronger acid will displace a weaker acid. Sulfuric acid is more corrosive, but AFAIK hydrochloric is a stronger acid, so theoretically a hydrochloric acid bath could replace sulfates by chlorides the way sulfuric acid replaces carbonate by sulfates.

It will be a subtle effect.

Comparison of solubility of CaCO3 vs. CaSO4 on addition of HCl solution:

(pH and solubility): http://www.chemistry.nmsu.edu/studntres/ch...solubility.html

I don't think we have seen any evidence of sulphate dissolution in all our time at Meridiani have we? So wouldn't any liquid have been a saturated solution?

Very indirectly and speculatively, Serpens. Some think that the Anatolia features are caused by dissolution of the evaporitic sandstone along joint fractures. No proof, really, but then, no dis-proof.

--Bill

For those who just want to have a short illusion of viewing 3d I built a primitive web site with java script, which does the flickering for you.
Just store the attached HTML file to your local disk and open it in your browser. If you click on the button "flicker" the view should permanently switch between left and right picture.
It does a good job on Chrome. On Firefox it seems, that the pics should have been downloaded before into the cache. Doesn't work on IE.

In the two text boxes you copy the URL to the original pancam/navcam/hazcam pictures.
http://marsrover.nasa.gov/gallery/all/1/p/...JYP2585L2M1.JPG
http://marsrover.nasa.gov/gallery/all/1/p/...JYP2585R2M1.JPG

Or use the exploratorium server:
http://qt.exploratorium.edu/mars/opportuni...K3P2591L2M1.JPG
http://qt.exploratorium.edu/mars/opportuni...K3P2591R2M1.JPG

For the NASA server you can also use the HTML url, it will be changed to JPG automatically:
http://marsrover.nasa.gov/gallery/all/1/p/...YP2585R2M1.HTML

Or more likely some form of altered basalt. The sulfates that (probably) once covered Cape York are mostly or entirely eroded away.

Sulfates generally do not exhibit pH dependent solubilities because the sulfate anion is a very weak base. In other words, its very hard to protonate sulfate. Perchlorates, nitrates and halides are also very weak bases, but the solubilities of their metal salts are often high because they are monovalent anions. Sulfides, carbonates and phosphates are often pretty insoluble due to their high charge, but all are also good bases. For sulfides, carbonates and phosphates (for example) exposed to acidic water, a set of simultaneous equilibria involving protonation and dissolution steps are present. If the pH is specified, it's not horribly difficult to solve these simultaneous equilibria for the concentrations of each ionic species, even if multiprotic events occur.

Hoping this doesn't bring back bad memories of college chemistry!

This is genuinely awesome.

-m

Yes, thanks so much!
I remember one flicker gif when Spirit went down Husband hill years ago, but nothing since then. I can never find 3D glasses anywhere and crosseyed is just annoying.

Superb! I've been really enjoying the flickering views being posted lately by Jam Butty et al - now I can choose my own! Well done MI!

Also works on Safari.

"Munro" (sol 2688).

Tisdale in colors, Sol 2688 :

.

Munro looks almost like a scoracious basalt lava with big xenoliths in it. This could be *very* interesting...

John

Same rock, in anaglyph :


And crossed-eyes :

Small update of the flicker page: Setting size and flicker frequency is possible.

Munro rock ("Munro ?" "Yes ?" "You ROCK !" "ow")

Hmmm…

So, this rock, in colors, anaglyph and crossed-eyes. Enjoy .

Wow, thanks MI... briliantly simple bit of software,
seems to be working well in Firefox 6

Munro and Tisdale in colour
L456 Sol 2688
Click to view attachment
Click to view attachment

This rock might not be going to win any beauty competitions, but it sure is fascinating...

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You'll never guess which rock...

Thanks Ant. Brilliant.

Looks like Munro's the current theme! What a strange conglomeration of rock! I wonder what it would do if you kicked it – shatter in pieces or hold its own.

Click to view attachment

Makes me think of a pile of dried-up debris left after a tsunami.

John or other experts, could one of you give us non-planetary geologists a paragraph mini course with some definitions/descriptions and why this could be *very* interesting---thanks in advance.

here is that rock...(again)

Click to view attachment

... it looks like a shatter-cone in Dedham Pudding-stone

Floyd:
Xenolith means it may have rocks from other places embedded in it, so it's two (or more) birds with one stone (no pun intended); saves travel time nicely for Oppy.
That's the limit of my geology though....

I'd call it a breccia, though I can see the possibility of John's xenoliths. Tisdale also has a similar colors and texture, though not quite as decrepit, so it could be the same lithology.

"Xenolith" doesn't necessarily mean other places. Xenoliths are common in extrusive igneous rocks. Lava flowing up from underground can tear off and carry away chunks of rock from the walls of its conduits; these chunks of "country rock" don't melt before the lava solidifies. So you can have lava from some deep source incorporating chunks of rock from anywhere in the crust through which it flowed.

Still, I gotta say I read John's post and I was all, "what, you can say all that from one low-res JPEGgy color photo?"

The sundial of Oppy on sol 2688, 11h12 LT. The top of the gnomon makes me think of Titan

Getting closer to our target. Here's the latest navcam picture.
Click to view attachment

For me it resembles a Nimitz class' aircraft carrier. Should we call it USS Tisdale?

BTW, this last drive faulted again after 4m.
1F367000442EFFBMKSP1254L0M1.JPG
02690::p1254::02::2::0::0::2::0::4::front_haz_fault_pri15_4bpp

Back at Santa Maria (how long ago that seems now!) we saw a rock called "Terreros" which seems, to me, to have something of a look of Munro. I'm thinking of the bluish material that appears to be "splashed" over it (not saying it was splashed, that's just a visual reference, ok?)

Click to view attachment

One interesting thing... note what looks like two prominent round "holes" in the nearest end (more obvious in the 3D versions). There's more of about the same size visible elsewhere as well. My best guess is that these were once gas-filled vesicles which were exposed when the edge fragmented -- which I guess reinforces the idea that this is a chunk of basalt.

[EDIT: Incidentally, why doesn't the image included in the quote appear? Seems like in the past this worked nicely, but more recently the result is as above]

Nothing on the forum software has been changed.

I thought we didn't want the image to appear in the quote!

Phil