YellowKnife Bay - Page 23

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Posts: xxx

Reply: 441

PostPosted: June 3, 2013 6:55 PM 

Also the small depressions with apparently fixed micro-concretions.


Mark Wilson

Posts: xxx

Reply: 442

PostPosted: June 5, 2013 3:49 AM 

LOL... in 10 months we've only moved about 420m from the landing site, and we've been in the same spot since January. I think the wide ranging/roving exploratory mission people envisioned prior to landing isn't going to happen.


Posts: 1

Reply: 443

PostPosted: June 5, 2013 8:31 AM 

MPJ, Re your 438.
Your response illustrates exactly why it is difficult for us boring rock guys to defend geological observations here. From all the outcrop evidence it is clear to me that the 'bumps' are an integral part of the rock - I am not going to spend time giving examples (again). The problem is, you deny that I have anything to offer in the face of your conviction you are right about your microbial mat model.

Hort's lovely image in 439 shows clearly that the 'bumps' are in the rock and are slightly more resistant than the matrix they sit in. Furthermore, the image shows the downwind erosional tail from each 'bump', that is, from the wind blowing from bottom right to top left. This surface and its 'bumps' have been exposed for a very long time.

I am happy to be shown to be wrong, that is what science is about. However you must take account of all the evidence to hand to convince me, and not just a model which cannot account for all the evidence.

Kye Goodwin

Posts: 1166

Reply: 444

PostPosted: June 5, 2013 11:00 AM 

Hi Newboy. I'm glad you're still contributing. And yes, I agree that the material in the bumps on the rock at Yellowknife Bay, like the thin dark "coatings" on Whitewater Lake (Cape York), did not form on the surface of the rock, but instead it was already present in the interior of the rock and has been revealed by erosion to the present surface.

Curi's handlers seem to be showing an interest in what I've been calling sharp little trenches:

This is not the clearest example of these possible "subsidence" features that Curi has imaged and all the nearby rover disturbance might have had a role in creating it, but I'm still heartened that someone seems to have decided that this is worth investigating. I expect we'll see many more, as several have already been imaged.


Posts: 3465

Reply: 445

PostPosted: June 5, 2013 11:17 AM 

Sol 0291 MAHLI closeup animation of sun / LED illumination of micro channel near Cumberland rock:

with location links.

I am happy to see that a detailed MAHLI study of a micro channel has been done - including study using LED light.

newboy, I think your conclusions about the dented rocks are correct: they are NOT current surface features. However, that does NOT mean that they couldn't have been surface featurea at the time of their creation.

What I find absolutely fascinating is that the dent is oriented the same in every instance. What made the dent?

I don't buy the "fossilized water drop" idea - although it would be "proof" of yet another instance of water's action on Mars rocks. The "drops" are not always co-planer.

Why would the "fossilized drops" be harder than the matrix? Why would they be so uniform in shape and size?

BTW, there is a MSL Media teleconference today.

Thomas Lee Elifritz

Posts: 10

Reply: 446

PostPosted: June 5, 2013 1:58 PM 

The reason they are loitering here is that this is the lowest spot around and thus yields the oldest statigraphy and their theories of Gale crater formation have been shredded beyond salvage. I knew from the start this was the wrong place to put the rover, but who can argue with a committee of esteemed public servants on government pay.

Rounded pebbles. Meh. Big breakthrough.


Posts: 3465

Reply: 447

PostPosted: June 5, 2013 3:14 PM 

Summary of teleconference:

Curiosity is driving as I type towards "Shaler" - a suspected cross-bedded stream deposits - with a stop at "Point Lake" to examine dark, pitted texture rocks. DAN measurements will be done on the drive. Then a plus one year drive to the Mount Sharp entry point with science stops along the way.

NO science results announced. ( Yawn. )


Posts: 250

Reply: 448

PostPosted: June 5, 2013 3:35 PM 

newboy, sorry if i came up a bit rude - no offense intended but maybe a language problem (english is not my native language). I really appreciate your professional geologic advice and hints as I did for Ben (rip!) there is nothing boring about it.

Regarding the bumps: I understand your view but personally I find it hard to align certain features of the photographic evidence (see Hortons re 445 for instance) with your model of ancient embedded concretions now exposed by erosion just in the right time and location (in billions of years!) for MSL to photograph it.

What about all the rocks of all sizes and shapes without the slightest hint of either - the different color surface (coating?) and the bumpy texture lying around in stark contrast as well?

Is a (fossilized-)microbial mat model in a location which has been proven habitable that unlikely or absurd given the photographic evidence so far.

How could either model be sufficiently verified without human explorers with a simple hammer and chisel around? Wink

I really look forward to the professional conclusions in the future when the papers are out AND the real raw imaging data is published...maybe we can spot the embedded concretions in the interior of some broken rocks there Twisted Evil


Posts: 344

Reply: 449

PostPosted: June 5, 2013 3:55 PM 

On vacation, I visited Mercer Cavern (a limestone cavern) and was amazed at the variety of shapes seen there, including grape-like bunches of spherical formations. (Google cave pearls, cave coral, cave grapes, etc.). It's not clear if microbes were involved or just water seeps.

Looks like I have missed interesting discussions. With regard to bumps and coatings, Horton's point about previous surfaces is well-taken. One way of distinguishing features from previous surface deposition might be to see if the features tend to recur in planar layers on the exposed eroded rock.

Horton, with respect to the request in reply 431, could you point to a (or set of) mastcam candidate images within which to look for the chemcam scene? I don't know my way around MSL images as well as MER images yet.


Posts: xxx

Reply: 450

PostPosted: June 5, 2013 7:34 PM 

MPJ; I am being even more unscientific than usual here.

Hort's reply #445 gif of a "microchannel" is the clearest example of a friable humic soil I've seen in any of the MER or Curi images so far. It fairly screams microbial involvement in its current development. I'm wondering also why would sterile surfaces that have been untouched by microbes and indeed water have the uncanny appearance of true fertile soils full of microbes on Earth? Shouldn't they look like almost sterile sands instead?

I'm looking forward to the in depth results of the investigation of that area in a few months time. But of course the likelihood is that nothing new will be found and the visual evidence will once more be confounded.



Posts: 3465

Reply: 451

PostPosted: June 8, 2013 9:18 PM 

Sol 0297 enhanced difference color panorama (right eye ):

Sol 0297 enhanced difference color panorama (left eye ):


Posts: 3465

Reply: 452

PostPosted: June 10, 2013 6:08 PM 

Sol 0298 false color 3D of peculiar veins:

with location link.

No, it is NOT a rib!


Posts: 3465

Reply: 453

PostPosted: June 10, 2013 7:47 PM 

Sol 0298 false color 3D of peculiar rocks:

er, what?!


Posts: xxx

Reply: 454

PostPosted: June 10, 2013 8:19 PM 

Hort; Re. your reply 452. Following on the theme of my 450. The uploads today show areas that look "wet" imho. Hope they do some in depth chemical analyses, especially of the areas where there are some discrete dark brown concretions. Those Gypsum veins are also remarkable the fine structure seems to suggest that they are made up themselves of light microspheres. Their orientation also suggests that they might be current provenance, not past veins covered in layers of soil. i.e. the Gypsum making process is ongoing up to this sol.



Posts: xxx

Reply: 455

PostPosted: June 11, 2013 1:40 PM 

June 10, 2013: The Imaging Node is pleased to announce the release of Mastcam, MAHLI, and MARDI EDRs and RDRs for Sols 0-179.


Posts: xxx

Reply: 456

PostPosted: June 11, 2013 1:42 PM 

New PDS to read on new data products.


Posts: 1

Reply: 457

PostPosted: June 12, 2013 7:32 AM 

MPJ - 448

I love your observation "your model of ancient embedded concretions now exposed by erosion just in the right time and location (in billions of years!) for MSL to photograph it."

That's geology. You sum up exactly what makes our science so wonderful. It would be fun to take you to see billion year old rocks on Earth so that you get the idea on representative sampling of the past. We rely on the limited outcrops at the surface to interpret the origin of the rocks. So what you might perceive as a rare chance is not. The rocks we see at the surface are usually a small sample of a much bigger pile of similar rocks not exposed now.

Then, looking at a rock such as Hort's 453. We can say the bumps are distributed THROUGHOUT the rock. If you are not used to looking at 3D rocks, try this. The bumps are concentrated in bands that start in the top left of the image and extend down to the bottom right.

Now think of a layer cake (with raisins!). Cut the cake obliquely in half. That is what the image is showing, with the oblique cut going from top right to bottom left. It is a bit more complicated, in that harder layers have weathered slower than softer rocks underneath them, giving the stepped appearance.

I hope this helps to explain why we know the bumps are in the rock.


Posts: 3465

Reply: 458

PostPosted: June 12, 2013 8:49 AM 

Sol 0297 enhanced difference false color detail of outcrop contact(s?):

with location link.

newboy, I appreciate your observations.

Are we looking at three rock groups here? The "red" one is sandwiched between a "blue" one and an "orange" one?

The red layer seems to have many finer layers - capped with a lighter ( gypsum? ) layer.

The puzzle of the "concretions" in reply 453 is that not only do they appear in distinct uniformly spaced horizontal layers - they also appear in some places to be aligned vertically too! There also appear to be layers with no ( or very few ) concretions.

How does this all square ( Squyre? ) with the "raisins in the rum cake" model of concretions?


Posts: 250

Reply: 459

PostPosted: June 12, 2013 11:18 AM 

newboy, thanks for your explanation and demonstration! You sound that confident with the 3D view (and even without it before) and your interpretation of the bumps being distributed throughout the layering that its hard to contend your conclusion. Yet I still have some doubts of that conclusion mainly due to other samples showing them bumps (only) on what appears like a coating (remember the ChemCam peculiarity currently under investigation that shows an abrupt change in signal on many rocks after the top layer is penetrated - excluding the dust) on otherwise different appearing rocks. Maybe that darn dust of Gale crater is obscuring things to the point of faulty perception (including me of course).

That almost top down imaging 3D of horton really appears like a layer cake with bumps on every layer but what would be the visual difference if these bumps are more recent features which just happens to appear on exposed surfaces - eg the upwards facing exposed sheets of that bedrock units (sediment layers likely)?
Or to retain your comparison: what if you cut that cake obliquely in half and due to some odd reaction with the surrounding air the new exposed surface of the cuts develops bubbles? Or even more pictorial after some while the exposed surfaces of the cuts develops circular specks of mold and you photograph it - would you conclude the mold is distributed throughout the cake as well from the resulting picture?

Without having examined a real (fresh) cross section I think I will have to retain some doubt regardless of your expertly explanation and will continue to monitor this closely. Wink

Additionally I would say such regular concretions distributed throughout layers of sediment would be highly interesting too for astrobiologic reasons due to them showing tightly similar features like similar kinds of small scale fossils in related discrete locations.

Some more results from the analytical instruments seems interesting too:

APXS elemental scan revealed the following constituents of the "Snake river" data point in YkB:
SiO2 (~43,7%)
FeO (~23,6%)
Al2O3 (~7,4%)
CaO (~6,9%)
MgO (~6,4%)
SO3 (~5,4%)

A hint of degraded carbonate rocks perhaps or just Martian cement? Smile


Posts: 3465

Reply: 460

PostPosted: June 12, 2013 2:37 PM 

Sol 0300 false color panorama of dark rock outcrop:

with 3D details.

Looks like this one was selected for analysis:

Here is the sol 0302 view of the outcrop:

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