On the Road Again - volume 5 - Page 10

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Kye Goodwin


Posts: 1166

Reply: 181



PostPosted: February 18, 2010 11:44 AM 

serpens, re your 174, It is good to see Dr Burt blogging again at UMSF. I looked through their Concepcion thread and found a few of his posts. He is not allowed to discuss the impact-surge hypothesis and jokes about this in 238: "(Or impact; sorry, I didn't even stick my little toe in...) ". Yes he does offer a slow climatic cementation model for the fills. I did too for a long time, but now I have to put the surge explanation first because I'm pretty sure surge has happened across Oppy's neighborhood since the Victoria and Endurance impacts.

You write of layering. In my scenario the layering in the bright rock was created in a much earlier event than the fracture fills. It looks like there were lots of fills in this area pre-Concepcion, maybe more than most places by the number visible on ejecta. I don't know if the surge that filled some fractures with fines produced any layered rock at all. It could have somewhere. The only layered rock that I attribute to post-Victoria-Endurance surge is the thin layer of coarse-grained crudely-bedded rock that covers parts of the raised rim of Endurance Crater:

LWS


Posts: 3062

Reply: 182



PostPosted: February 18, 2010 11:52 AM 

Hort;

Your last #179 3D is truly awesome. I was trying at making an anaglyph of today's releases myself but just couldn't get the features to show properly. Yours show them all.

It looks as if most or all of the berries on the melt or covering "tissue" are not actually an intrinsic part of that "tissue" but drop from it or leave clear indentations in it. One such "mould" shows extremely clearly in your 3D. It also looks as if we are seeing small fairly distinct stems on "young" but somewhat distorted berries.

If they continue to take such MI's and expand on them with a dedicated search for good examples of berries on stems (concentrating on the stems) we might get a clearer idea of what some of the berries really are.

Anyone else noticed that the concepcion berries are much smaller than the eagle berries and similar in size to the erebus ones?

Winston

hortonheardawho


Posts: 3465

Reply: 183



PostPosted: February 18, 2010 12:19 PM 

sol 2158 colorized EDF ( Extended Depth of Field ) MI:

with location link.

An APXS measurment is in progress for this area.

I think the berry "wind tails" where there can't be wind tails will finally create a few "aha" moments for "folks that matter".

Naaah. I'm sure there is a rock guy explanation. There always is.

Bill Harris


Posts: 72

Reply: 184



PostPosted: February 18, 2010 2:19 PM 

Serpens, post 159:
"Bill, In a wicking scenario wouldn't this be a saturated solution with a neutral ph? So we would have ions of magnesium, sulfate, with some iron and who knows what else all wanting a home. Outside my comfort zone. I haven't been able to find any data on the composition of previous fills although they seem to have a false color signature similar to the berries which could imply hematite content."

We'll know more soon enough. Mi's with APX's at three spots on ChocHills (host rock and two types of "fracture fill") should give a good handle on the gross chemistry. Which is limited since it doesn't tell what the mineral variety is (ie, CaCO3 can be calcite, aragonite or vaterite, depending). Given the source, I'd also guess anions/cations as Mg, Fe, SO4 and whatever trace ions, and who knows what would crystalize out of that brew.

I'd like to see some sort of brush or RAT on the fill to see the crystalline structure (looks sort of crypto- from here).

And next an MI and APX of the weathering "rotten rock" nearby, I'd like ot figure why this stuff is crumbling so.

We can also get an idea of what sort of facies change may have occurred before we head downhill/section.

Devilish site-- cresting more questions than answers.

--Bill

Bill Harris


Posts: 72

Reply: 185



PostPosted: February 18, 2010 2:38 PM 

TRim Parker has a new Oppy Route Map posted. Has an interesting "adaption":

http://www.unmannedspaceflight.com/index.php?showtopic=681&pid=155775&st=2670&#entry155775

--Bill

James


Posts: 3

Reply: 186



PostPosted: February 18, 2010 3:02 PM 

Hort your 183,
Dark tiny 'granules' inexplicably resisting gravity- or wind-abetted movement... nascent blueberries forming in place? Also, signs of wind-scour and fluting on the otherwise smooth rock surface.

hortonheardawho


Posts: 3465

Reply: 187



PostPosted: February 18, 2010 4:36 PM 

I thought some of you might be interested in the MI colorization process so I created this montage to illustrate the steps.

I'mmm off to see the sunset - the wonderful sunset of noolll...

Barsoomer


Posts: 344

Reply: 188



PostPosted: February 18, 2010 5:28 PM 

link

New status from yesterday. They seem to be sticking with the impact melt idea.

Quote:

The instruments on the rover's robotic arm (IDD) have been investigating targets on the rock called "Chocolate Hills." This rock is of interest because it exhibits a dark rind or crust that may be impact melt. On Sol 2152 (Feb. 11, 2010), the rover made a small turn to reposition the robotic arm for targets on the surface of the Chocolate Hills. On Sol 2154 (Feb. 14, 2010), the IDD collected a Microscopic Imager (MI) mosaic, then placed the Alpha Particle X-ray Spectrometer (APXS) on a light-colored rind called "Arogo." On Sol 2157 (Feb. 17, 2010), the rover repeated these two sets of measurements on a target called "Tears."

Further investigation of this rock is expected before the rover drives away. As of Sol 2157 (Feb. 17, 2010), the solar array energy production was 305 watt-hours with an atmospheric opacity (tau) of 0.432 and a dust factor of 0.496. Total odometry is 19,335.35 meters (12 miles).

serpens


Posts: 169

Reply: 189



PostPosted: February 18, 2010 6:15 PM 

Hortonheardawho - Your image at 183 is unbelievable. For me this image is pretty clear confirmation that this is a fracture fill. You can see the clear circular indentation where it has formed around part of a berry that must have been protruding from the side of the fracture.

I can see 1 maybe 2 wind tails formed in the underlying rock. But I would think that these have formed through erosion after impact.

John


Posts: xxx

Reply: 190



PostPosted: February 18, 2010 6:45 PM 

If it was impact melt, would not you figure ther'd be breccias lying around?????

LWS


Posts: 3062

Reply: 191



PostPosted: February 18, 2010 7:02 PM 

Serpens; Re your #189. The logic is somewhat counterintuive between your 1st and 2nd parapraphs. i.e If you accept that Horts image shows a fracture fill because there is a clear circular indentation formed around part of a berry that must have been protruding from the side of a fracture. How is that related to seeing 1 or 2 wind tails formed in the underlying rock possibly through erosion after impact. And why did you omit to mention the clear indentations presumably left by berries with stems on the presumed "fill"? Or were those obviously wind tails also?

Winston

Barsoomer


Posts: 344

Reply: 192



PostPosted: February 18, 2010 8:05 PM 

Rock towards lower right that is casting a long shadow has jagged edges. It seems clear that it has broken apart and the other piece is lying next to it. The surface where the break occurred is nonplanar---it is quite complex. This might be an opportunity to look into the deep interior of a rock, although the rock otherwise does not seem noteworthy.

Barsoomer


Posts: 344

Reply: 193



PostPosted: February 18, 2010 8:12 PM 

Rock near bottom at middle. The grain at the right side of the rock seems to be almost perpendicular to the grain at the left side.

serpens


Posts: 169

Reply: 194



PostPosted: February 18, 2010 8:51 PM 

Winston. Apologies because I don't understand the question. Yes there are a couple of apparent windtails eroding in the rock - but these have not weathered down to stalks. I thought that was what Hortonheardawho was refering to when he mentioned out of place wind-tails - ie how could they develop underground in a vertical crack. They couldn't, so this erosion could only have occurred after exposure post impact. This does seem yet another data point to imply that the 1000 year old crater is in fact much older

But I cannot see any evidence of berries with stems on the fracture fill? There are certainly some indentations and ridges, impressions of distortions from cracking and possibly some dissolusion. As Bill says this would have been a complex brew. But I would appreciate it if the eagle eyes of Bill and Ben could either confirm or deny my interpretation.

Ben


Posts: 2270

Reply: 195



PostPosted: February 18, 2010 9:51 PM 

Barsoomer; I think we may be looking at a bedding plane in #192 and the jagged edge could be a fracture surface but agree it would be a good one to look at.

What you see in #193 is a two dimensional view of bedding planes that (slope ) dip to the lower right.

A tough measurement to make in the field if only one dimension is present. Wink

Serpen; Don't worry if you are wrong I will be the first to tell you. Smile

Ben


Posts: 2270

Reply: 196



PostPosted: February 18, 2010 9:55 PM 

James; If those specks are surficial they may be tiny grains of the eroded fracture fill but I can't explain why they cling to the surface. Any ideas?

LWS


Posts: 3062

Reply: 197



PostPosted: February 18, 2010 10:23 PM 

Serpens; I must apologize for not framing the question properly. I suspect your windtails are my stalks or stems and vice versa. One of the 2 windtails you are referring to is firmly lodged on the rock surface below the "fill". The other, I think, seems to be still perched on the edge of the fill. They both have what look to me like stems attached and not windtails, based on the diameter of the putative stems and their apparent consistency with the somewhat distorted berry to which they are attached and not with the rock surface matrix. They do not in any way resemble the classical windtails that were imaged by the MI in Enterprise? crater around sol 120 or thereabouts. Those berries presumably did not form where we now see them and I have some difficulty in seeing how the wind could have carved the "wind tails" or stems in the somewhat protected position they are now in, covered by the "fill" or melt which is obviously subject to erosion or cracking and would have formed a more complete cover in the past to what we see now.

Re. evidence of berries with stems on the fracture fill. The berries with stems attached are on a portion of "fracture fill" that has broken off the main fill and has a few distorted berries clustered (or even perhaps melded) together, some with what looks like stems, again bearing no resemblance to typical wind tails.

Winston

LWS


Posts: 3062

Reply: 198



PostPosted: February 18, 2010 10:29 PM 

Ben; Re your #196, those specks can be seen around every berry imaged on the surface of the evaporite rocks from Eagle Crater until now. I think they make up the bulk of the typical berry body enclosed in some sort of binding matrix.

Winston

Barsoomer


Posts: 344

Reply: 199



PostPosted: February 18, 2010 10:39 PM 

Serpens, have you looked at Horton's 3D stereo version of the same MI scene (see reply 179)?

In stereo, the crust has a bent, somewhat crumpled appearance. Wouldn't fracture fill be brittle, rather than ductile? If so, do you think the current 3D configuration is a faithful representation of the shape of the rock on which it would have been draped? The middle of the crust also appears to be suspended above the rock it is currently on, as though it had bent from its original configuration.

One of the berries that Horton referred to is in a sheltered location below the crust, and it is attached to a small piece of stalk that is unattached at the other end. I think Horton's point was that this could not possibly have resulted from post-impact wind erosion, and of course it would not have been subject to pre-impact wind erosion if this was an enclosed fracture fill

Bill Harris


Posts: 72

Reply: 200



PostPosted: February 18, 2010 11:02 PM 

Serpens--

The more MIs I see the more it looks like a microcrystalline coating. Even down to impressions of berries as the fill formed around them. I agree with your interpretations.

The stems and wind-tails are an interesting side-effect of the wind erosion here, but that is about all. I wouldn't put forth much effort worrying about them. We need to look at the other examples of this "fracture fill" feature.

I've got a revised MI/APX index image at Chocolate Hills posted:

Sols 2151-2158.

--Bill

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