Turtle with a top hat?

Two pancam images from Sol 3074

A color flicker gif of Stu's rock...
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And a view of presumably 'Whitewater Lake'...
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[strikethrough]All[/strikethrough] Many MI images are "inverted" compared to Pancam and Navcam images.

--Bill

Curiosity like!

We are starting a "new mission", after all...

An anaglyph of "Stu's rock":
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The image reversal depends by the IDD configuration. If the wrist is down the MIs are right side up but if the wrist is up MIs are upside down. I'm not sure if the joint values are reported in the telemetry that is publicly available.

Paolo

Ah, let me rephrase that and say "many" instead of "all". After I figure the context I typically flip the image to be non-inverted.

Nice area for this stop.

--Bill

I really like the idea of an impact orgin for the spherules. Four billion years ago, impact rates would have been very high. Maybe every few million years, a large impactor would have formed a 100 mile class crater and thrown out a shower of spherules. In between impacts, water erosion laid down sediment forming mudrocks.

In the Barberton greenstone belt of South Africa there are several beds of spherules which most believe to have been formed by large impacts 3.2 billion years ago. The beds vary in thickness from a few centimeters to 2 metres. The spherules are described as accretionary lapilli of up to 3mm in diameter, although a few are as much as 10mm in size. They are described as having a concentric appearance with sometimes distinct nucleii, and consist mostly of microquartz chert and sericite. The spherule beds are found in layers of chert. Banded iron formations and shales are also found in the region.

Apart from impact, at least two other theories have been advanced for the formation of the Barberton spherules. One is that they are silcified marine carbonate ooids. The other is that they are formed by volcanic processes followed by hydrothermal alteration. The spherules are believed to be impact produced because of high concentrations of iridium (up to 2700 ppb) and other platinum group elements. They also have a high nickel and chromium content, and chromium isotope ratios have also been interpreted as evidence for impact origin.

I wonder if APXS could detect the iridium?

Image of Barberton spherule beds

Nice, here's a cross-eyed pair:

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Mark

Couple of blasts from the past...

Gypsum vein imaged on Sol 3049...

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...and 456 colour view from Sol 3070...

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Naw... Triceratops..... whose a nice tricie... pats rock

New MIs of the eroded massive rock with the bluish resistant areas. This may be the most beautiful MI of all.

http://qt.exploratorium.edu/mars/opportuni...00P2906M2M1.JPG

The resistant areas are particularly interesting.

--Bill

result of Sol 3076 brush on Whitewater Lake (must be taken upside down !):

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Link to Image

brush movies:
PanCam
HazCam

Cheers, Udo

here is my take on a rock (is there a name?) that was taken on Sol 3070 (L456)
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edit: 'wolverine?'

Isn't that Kirkland (the Fin rock), where the previous MI was done? (The one that is getting all the attention.)

Kirkwood.

Slightly "artier" view of Whitewater Lake's recent brushing...

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Is this a discrete location where they identified clay on Cape York? Authigenic clay cementing?

Serpens, this area is "close" to where the phyllosilicates were ID'd. The sensor resolution was fairly coarse and I take any location with grains of salt.

By thinking "authigenic clays", that is a term that covers a lot of territory. Authigenic implies to me that the mineral was formed in-situ by precipitation, recrystallization or metamorphosis. One mechanism could be impact-induced low-temperature hydrothermal activity. We need to see if there are the proper puzzle-pieces to put that picture together. The scenario I favor is that the light-toned material of Whitewater represents an ancient soil horizon where the clays were formed authigenically by weathering of volcanics or impactites which is overlain by the coarse blue-toned "surprise spherules" (of unknown affinity) of Kirkwood, which are impact-related. And they are not even related to the Endeavour impact as they represented the surface or subsurface at the time of the Endeavour impact.

One paper I'd like to read is:

and I'm trying to pull strings to get a copy.

At least, this is how the puzzled-pieces are stacking up for me now. As we get more info in, and if my chicken starts to look like it has duck-feet, I'll revise my views...

--Bill

I don't know, but it may be a bit premature to be talking about authigenic clay minerals at this point. Once we find and identify the clays, and see them in context, an authigenic origin might make sense.

I've been sort of eyeballing the published CRISM phyllosilicate overlay with respect to Eduardo's route map to estimate Opportunity's location relative to the anomalies. Serpens' question encouraged me to do a quick and dirty overlay of the CRISM anomalies on Tesheiner's route map. This overlay could be off by a few meters here or there, but it will give people an idea of where this interesting outcrop is relative to where CRISM's lower resolution imagery says it should get interesting.

The paper that the CRISM map came from was titled, "Phyllosilicates and sulfates at Endeavour Crater, Meridiani Planum, Mars." The image caption said (in part), "Distribution of Fe/Mg-phyllosilicates (red) and polyhydrated sulfates (cyan) in CRISM spectral parameter maps."
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edit: I used the only CRISM phyllosilicate map of the area I am aware of. If anyone knows of a better one that's publicly available, please speak up.

That's the best CRISM map I have seen Cosmic. But if the map is accurate it does beg the question as to why Oppy zigged to avoid the clay bearing area? The ground in that area looks pretty driveable in Navcam so perhaps as Bill implies the clay location isn't all that clearcut.

Bill, the reason I mentioned authigenic is Whitewater seems to be reasonably well cemented mudstone/siltstone and I would have thought a product of CY erosion would be the most likely provenance. The APXS will give a few indications I trust. Those spherical (clasts? concretions? nodules?) in the Whitewater MI are also different.

But if you would indulge me, Steve's description of the spherule layer made me think immediately of my favourite Larsen coffee mug:
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I don't think she zigged to avoid anything. They simply saw some outcrops they couldn't resist.

Tom, very good overlay of the Route Map and CRISM map. I've been meaning to do that forever.

"Authigenic" in that the clays were produced relatively nearby, as opposed to allogenic where the clays were created in another area and then transported to this site via aeolian or even fluvial processes. We are on the same page, although in different paragraphs.

One puzzle piece that I've had sitting off to the side since the traverse leg along Shoemaker Ridge was the set of orthogonal, light-toned lineations that coincide with the strongest CRISM clay signature. Oppy was closest on Sol-2742-2746, and as you recall, I informally named that area "Secular City". Given that we have since discovered the Homestake-type veins which are low-temperature hydrothermal, this spot should be on our to-do list.

--Bill

Isn't Whitewater above Kirkwood in the section (or am I hopelesly confused)?

The map that you used comes from Wray etal, GRL 36, L21201 (2009) I believe. Since then there was oversampled CRISM data, as described in this abstract. There's also a different looking (but very low resolution) map in this abstract, although that appears to be based on Wray etal.

I haven't seen a proper map that shows the signatures on CY using the oversampled data - maybe someone else can point us to something public? But I would guess that the Wray etal data that your overlay onto the route map used has been superceeded, and the team is using the better oversampled data to say we're near the orbital signature.

Edit: BTW, from the latest update:

Someone remind me again, how do they determine mineral hydration with the Pancam? Which filter or combination of filters are used?

Righto. I was confused, tho not hoplessly (yet). Corrected the above post for posterity...

--Bill

EDIT:

...and then "uncorrected" it back to reflect the right lithologies.

Unless I'm terminally confused, Whitewater is the "light and fluffy" unit we've seen below the Kirkwood "blue and crunchy" unit Oppy looked at initially. Unless they've gone upslope and set up on one of the light and fluffy's up there.

Let me look and get back...

--b

The overall scenario you described does appeal to me (as a non-specialist onlooker). I think there are probably other impactite layers above Whitewater as well. Soils sandwiched between caps and floors of impact origin could be good groundwater traps.

Why do we stay at Kirkwood these endless sols ?
Why not proceeding a couple of meters uphill into the smectite area as already noticed in CosmicRockers' post #330 ?
CoscmicRocker's waypoint image

Opportunity drove through that area between sols 2749 and 2751 10 months ago during it's drive to Greeley Haven without any deeper attention to this hopefully interesting area.

Cheers, Udo

No interesting features were seen as Opportunity drove through there, except perhaps for some gypsum veins. Where Opportunity is now there are tilted outcrops loaded with strange new "berries" and fine-grained mud-stone-like rock. Fantastic new discoveries to study. This is not a bird in the hand, this is a cage full of birds!

If and when the clays are found, it would be best to find them as part of an intact outcrop, not as a layer of dust or rubble, which is all that might be found in the red blotch areas.

(My non-geologist opinion)

Even more confused now. I think you had the rock names the right way round before, but the light-coloured finegrained Whitewater is located above darker, spherule-rich Kirkwood.

CLAY: We may be right on top of it already. Crism only sees the big patches.

The rover drove through the clay rich signature last year, on its way to Winterhaven. It was pretty boring, so maybe the clay is mixed into the soil. They did see an outcrop called 'Hooggenoeg', which I think looks a little like the spherule rich outcrops seen from a distance. They also saw 'Sheba' and 'Kirkland lake' boulder field.

Last October 22nd, Road to Endeavor blog

Hooggenoeg image

Where the rover is right now may very well be a lot more interesting than the clay rich areas. It is definitely a little north of the clay rich area, although the story here is probably tied into the clays in some way.

They base this on a negative slope from 934 to 1009 nm (I assume with specific slope characteristics for imaged material as hydration shouldn't be the only cause of a 1009 nm absorption feature). All I could locate were abstracts.

http://adsabs.harvard.edu/abs/2011AGUFM.P22A..02R

Does anybody know why Oppy went north around CY instead of heading south towards the apparently more extensive clay deposits there?

Because they had to find a north-facing slope to survive the winter.

Phil

There were some quotes in the recent PS update about the CRISM signatures and our current location.

So it sounds like this is the place to be. As I mentioned above, they may be working with better CRISM data than what we've seen.

Ok, thanks Phil.

I was actually thinking residual clay Bill. Clay components (possibly present in the mudstone on deposition or formed in situ) weathering out. One of a multitude of potential scenarios. Some of the discussions within the team must be fascinating.

Thanks, fredk. I have been searching for the oversampled data but so far have come up short. I also recall those Arvidson quotes from Salley's update. It appears that the continuation of these outcrops to the south goes right through the old CRISM anomaly, so perhaps the oversampling technique simply expanded the area of detected phyllosilicates to these outcrops. There's no doubt that the people driving Opportunity know where they are going.

Dan: Here's a little more detail about detecting mineral hydration with the pancams. I think hydration could more reliably be detected if they could see deeper into the infrared band, but the R7 filter does see part of a water absorption feature. If it was still working I think the mini-TES would have been the best instrument to use to detect hydration.

A few recent papers have mentioned using the pancam filters to calculate a hydration index as serpens described. See the attached figure from Arvidson et al, "Opportunity Mars Rover mission: Overview and selected results from Purgatory ripple to traverses to Endeavour crater" JGR 2011.
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Ah, to be a fly on the wall.

Interesting post-brush Pancams of Whitewater down that afternoon. That "mudstone" appears to be remarkably soft, or at least the weathering rind is. And although the outcrpo looks light- and "reddish-" toned, knock the crust off and it's... bluish. Imagine that, and that will need considerable thought...

Meanwhile, off to figure out where we are on the outcrop and in the section...

--Bill

Post-brush Pancam image mentioned above:

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and a quick try on a Pancam/Microimager merge:

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This particular spot on the Whitewater Lake outcrop has been labeled Azilda. A quick search gave me the relationship between both:

Whitewater Lake is located in Rayside, Snider and Creighton townships, near the town of Azilda.

This one is from way back on sol 3052, before heading west.

Well grey more like. Basaltic/glass based sediment weathering to nontronite? Another potential for hydrothermal influence there.

Oppy and her big sis are obviously locked into a sibling rivalry game of "Anything you can do..."

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Phobos transit seen by Oppy. The Sun was overexposed but you can see the transit on a reflection just above the glaring Sun...

The Sun was horribly stretched, as usual. The exposure was just dandy.

The Whitewater Lake and Kirkwood outcrops panoramic is finaly complete .

I'd figure after 8 years you all would know how how to take a picture of the sun!

-- Pertinax

Sol 3078 animation - 4x speed

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Was not able to find this images in the exploratorium folders.