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Stereo from one of the new Kirkwood MIs.

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Closeup of bottom portion (rotated through 90 degrees).

Nice. I love those stereo concretions little ball-shaped thingeys.

There was a very tiny slip downslope between sols 3246 and 3247, as you can see by comparing the wheel to the surrounding rock:
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There's also some dust movement - look along the lower edge of the band of dust below the rock overhang.

Concretions? Have they found something new? I thought there were a lot of possible options open including accretionary lapilli, impact spherules, or devitrification spherules as well as concretions. Arvidson I believe favors lapilli?

Oops - a slip from a non-geologist!

A couple more:

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Looks like they attempted to do a RAT grind of some variety on sol 3251. It doesn't look like much was ground, but a bit was, and there's Pancam images available...

Exciting to see some action!

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Parallel eye stereo this time.

Note the lack of any apparent transition between the sliced berry and the sliced ridge just above it.

That must be the streak test they talked about in the last Planetary Society rover update. Some snips:

"We want to test the idea that there might be a little bit of hematite in the newberries, said Squyres. "We know that the blueberries out on the plains are very rich in hematite. The newberries aren't anywhere near that rich in hematite but they could have a little." With the Mini-TES and Mossbauer now out of commission, it's more difficult to discern hematite. But hope is not lost. "If you go back to geology 101, one of the very first things they teach is a streak test," said Squyres....

"...So we're going to do a little light RAT grind into a dense concentration of newberries and we're going to take a pic of the cuttings with Pancam and we'll see what we see. It's a streak test. It's geology 101."

"The idea is that something is cementing the outsides preferentially and it might be hematite or it might just be silica or some kind of sulfate but at such a low concentration we won't be able to tell," said Arvidson. "If there is hematite in the crunchy outside layer, it should turn bright red."

Talk about the ultimate work-around for faulty instruments. I'm thinking that it wasn't all that long ago that someone in the forum reminded us of the streak test with regard to hematite. ...very cool stuff...

Ok image processors...it's almost time to crank red up to eleven.

--Bill

Taken from a couple tweets by Emily Lakdawalla at LPSC:

Squyres: Origin of whitewater lake uncertain. If impact ejecta, it's not from Endeavour.
Squyres: Whitewater lake rocks old, record epoch before Endeavour.


This confuses me. The second statement makes sense. Whitewater Lake type rocks were part of the pre-Endeavour surface that was lifted up to form the crater rim during impact. But the first? I don't see how that conclusion could be drawn.

But the second is the same as the first - it's older than Endeavour, the old target material lifted up to form the rim, and then covered with Endeavour ejecta. That target material might originally be ejecta as well, but from other nearby and older craters, not from Endeavour itself.

Phil (I was in the room too)

Wow. It gets complicated, but I think I understand a little better: A pre-Endeavour surface consisted of regolith (ejecta) as well as bedrock. Once the Endeavour impact blasts that surface up into a crater rim, I would consider all of it now to be Endeavour ejecta, but I see the point of drawing a distinction. I'd be interested in knowing how they can tell Whitewater Lake was pre-Endeavour regolith and not bedrock.

Or do I still not understand at all?

Regolith is a recent soil - don't just think of a few meters of debris around a little crater - this could be part of a km-thick deposit from a large pre-existing crater not far away, largely destroyed by Endeavour or 100% buried by the plains, but its ejecta, now a rock layer already extensively modified with veins, concretions etc., is the target material struck by the Endeavour impactor. As Squyres described it, that Whitewater rock was uplifted to form the rim and scoured by outflowing ejecta, getting bits of Whitewater including concretions broken off and entrained in the new ejecta (hence no sharp boundary between WW and the Shoemaker Formation (Endeavour ejecta) overlying it). But WW was a real rock, not just a bit of older regolith.

Phil

Spot on. Endeavour impacted the ejecta blanket of Miyamoto which would have been extremely thick in the area. As uplift rim it is almost certain that Whitewater was underground, not part of the original surface. The need to stand back a bit and put the tiny areas where we have ground truth in context has been discussed many times.

Thanks, I've got a better picture now. I guess you had to be there.

Actually, taking recent discoveries by Opportunity and Curiosity together I think one part of the picture is getting simpler. I must abbreviate here to avoid writing an essay.

Impacts throw up basaltic dust which settles back on the ground. There are areas of standing water and maybe other damp surfaces that trap this material as it blows around. Clay minerals form. Less frequent later impacts disrupt the stratigraphic sequence. We arrive.

Looking at the ancient channels to the South and East of Endeavour that cut the miyamoto ejecta there was a lot of water involved early on. This water and the resultant clays could of course predate Endeavour which could explain the presence of clays on the rim, the elevation helping them survive the later acidic water inflow. There is clear evidence of plentiful acidic water in the sandstone plains traversed by Opportunity. Acidic surface / near surface water during the volcanic phase interacting with deeper, basalt buffered groundwater makes for some interesting interface reactions and depositions.

News from the conference - Opportunity will now return to Boxwork (where it just came from), RAT a bit and spend conjunction doing APXS on that. Then it's off to Botany Bay.

Phil

Looks like Opportunity's second grind of "Sturgeon River 3" on sol 3253 went well, and she's now moved north toward 'Boxwork'.

Unfortunately neither of the public image sites has been updating for a couple days now.

Latest JPL update

Getting some images via the JPL site now. Sol 3253 "Sturgeon River 3" grind L257:

And an animated Gif
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I've never really been good at Overlaying Pancam Color over an MI image, but here is my shot at that.

Squires has apparently come down on the side of concretions to explain these spherules, but it would be nice to know what logic chain led to that decision. The spherules are the same material as the matrix I believe, so what is the cementing material? Life was so much simpler on the sedimentary Burnes formation.

Perhaps it was the result of the "streak test" that tipped the balance?

My first processed space image (and post here!): Opportunity's Sol 3244 tracks from the Pancam, in enhanced color. (I've been watching Emily Lakdawalla's tutorials.) I played with the levels some on each channel, because the image was initially very blue. I like the overlapping old and new tracks, and also the very visible red dust on the arm.

Welcome Elizabeth! About time!

Very well done Elizabeth, and Welcome to the Forum!

Thanks a lot Elizabeth for your 1st post and warm welcome to the Forum !

Beginning to survey post-conjunction drive routes, perhaps?

http://qt.exploratorium.edu/mars/opportuni...2M1.JPG?sol3262

Could be. I think the most direct route would be on the downhill side of Cape York and Nobby's Head.

Phil

Hi Elizabeth, and welcome aboard

Your picture remembers me one of my first imagery work, with the robotic arm in sight :



Fewww, 2005. Looks like a loooong time ago

The image was taken as part of a "drive direction" pancam mosaic, so let me add my 2$ to this bet.

http://qt.exploratorium.edu/mars/opportuni...00P2579R6M1.JPG

Call me silly but doesn't this look like saprolite bounded by unweathered rock? The alteration zones here reflect, as Squires put it, a dog's breakfast but could this be the elusive source of the clay signal? From everything we have seen the apparent water influences at Cape York seem to go well beyond local impact generated geothermal effects.

Indeed it does. And we've seen examples of a weathered and lithified paleo-land surface that has been uncovered by later impact and erosion. I'd like to see also what is lower in the section here before moving on.

--Bill

The monthly report is out:

Planetary Society Report

I likes the enhanced CRISM view of Cape York. The area of smectite clay is realy clear in that picture. I wonder when the enhanced view of the clays on the Southern side of Solander point will become available?

I liked the statement "As soon as conjunction is over, we'll be heading south to Solander Point as quickly as we can" . I wonder if that means that Oppy will head on the shortest path across the Endeavour crater floor to the base of Solander point. From that position Oppy could climb up to the clays and reach the clays within a few months.

I had assumed that Oppy would travel around the rim of Endeavour Crater and climb the Northern face of Solander Point, where there are no clays. By the time Oppy had reached the summit of Solander Point it would be Autumn and Oppy would need to wait until the following spring before decending onto the clays from above.

Either way I hope that Oppy's wheel does not break when she is on the interesting Southern face of Solander Point because she could not survive a winter resting on those clays.

Check out our discussion of that enhanced crism view starting with this post. It may be that the red region is just the ground-based determination of the Whitewater outcrops.

I can add more about the red region now. Ray Arvidson explained it at LPSC. The image does not show that patch however it is processed. Ray himself looked at the spectrum of each pixel in that area, and where he found the subtle indicators of the clays he was looking for, he made those pixels red. The distinction was too subtle to show up in the image itself but could be teased out that way. When he finished his map Opportunity was driving south just below the 'red' patch, and Ray had them slam on the brakes (so to speak) and take a hard right up the hill. After their circuit of the hilltop it was clear that the red patch matched the Whitewater unit very closely.

I don't think this precludes other clay outcrops on Cape York, as I don't know exactly how far Ray's mapping extended.

Phil

A very insightful post Phil. It has to be said that anything 'teased out that way' comes with a caveat, and the image itself as published has to be described as misleading, given the way it was made. It doesn't show any smectite outside the area directly inspected by Opportunity. Why not? I'm sure he believes very strongly in the case he is making and in fact (FWIW) I accept his conclusion.

Only in the sense that any reading of scientific data comes with a caveat. Using images to represent hyperspectral data is good for showing spatial relationships but positively awful for displaying the actual spectral information content. Hue in images can show you variation along a maximum of 3 axes (red, green, and blue). CRISM images can contain up to 500 spectral bands. There's no way to represent all that information in a single color photo. So the idea of looking at the spectrum at each pixel and identifying an important spectral feature and coloring in the pixels that have that feature is a perfectly valid thing for a spectroscopist to do.

All true, the science is not in question, my respect for the scienists is enormous. Also he's not to blame for the fact that the image went out months ago when the abstracts were posted and was discussed here with the limited information available to us at that time. Even so, I think hand-coloured pixels should be flagged up as such. He did that in his conference presentation but we wouldn't have known that (outside the conference) without Phil's post. I'm still not sure why no red pixels appear outside the area traversed by the rover when the CRISM smectite patch is much larger, especially southward. It would have been more convincing had this been done.

You gotta admire the methodology and perseverance that identified the potential target area although 5m per pixel would make for overlap, making localisation of what seems to be limited occurrence of smectite a bit difficult given Opportunity’s limited ability to ground truth the area. The APXS results imply aqueous alteration but unfortunately the identification of Whitewater as the source of CRISM smectite indications must remain a hypothesis.

Unless you're a mantis shrimp.

Get ready for more action soon! Although Curiosity will be in conjunction mode until the end of the month, brave little Opportunity will be back in action in only a few more days, and unless something very interesting has suddenly turned up, it will be time for another road trip.

Phil

Are they just being more cautious with Curiosity then? Conjunction is so boring for us, thank goodness its only every two years haha.

If Ray's mapping is objective then I presume that a computer program could be written to extend the map of smectite clay outcrops over a much larger area.

Such a map would allow it to be decided which side of the rim Oppy should explore as it heads South. If I remember rightly, clays have been detected both on the West side and on the East side of the hills of the rim and so in the long run a decision must be made which set of clay deposits to examine.

I think figure 1 of this article is the map you refer to.

www.planetary.brown.edu/pdfs/3954.pdf

Phyllosilicates primarily on the inner rim. 'Teased out' gives the impression of a somewhat subjective/intuitive judgement as part of a laborious analytical exercise. Wray's analysis indicates the possibility of a more extensive deposit on top of Cape York but Opportunity could drive across a clay rich area without the ability to identify it as such.

I'm curious on the length of solar conjunction too. The sun is only 1/2 degree (out of 360) wide on the sky, so why does solar conjunction occupy more than 1/720 of the time? Can the communication equipment not be pointed closely at the sun, and if not why not? I was sort of under the impression that the sun wasn't an incredibly strong radio emitter, but maybe it is...

It's simply a case of reliability. You do not want to uplink commands only for the vehicle to not receive them properly and thus throw itself into an X-Band fault or other safe mode.

This document on MRO : http://descanso.jpl.nasa.gov/DPSummary/MRO_092106.pdf : states

"An X-band link using BPSK begins to degrade near a 2-deg SEP angle."


On DS1 : http://descanso.jpl.nasa.gov/DPSummary/All_Article2.pdf

"For DS1, X-band up- and downlink, we considered an angle of 5 deg as the minimum at which to expect no degradation, and 3 deg as the minimum at which reliable communications could be planned. From October 20 to December 3, 2000, the angle was less than 5 deg, and from October 29 to November 25 it was less than 3 deg. The minimum angle was less than 0.5 deg during a scheduled pass on November 14, 2000. The 11-year solar cycle was near its maximum"

Indeed, even though the Sun is relatively quiet in the band used for radio communication, a single outburst could change a command into something quite undesirable. And on top of it the operators would have a very hard time to know which command have been randomly changed. So yes, it's about reliability and safety as far as I understand this also.