On the Road Again - volume 6 - Page 8

Drainage would be the subsidence, Of water no less. Unless someone knows of some other substance capable of being liquid on Mars.

Fred

Kye Goodwin.
What a pity that Bill Harris and Ben have left this forum s I am sure that either of them could provide significant insights into the ‘micro-channels’. Although perhaps Ben may comment of the Mars Geology forum. But Hortonheardawho’s 3-D images from post 131 reveal a couple of interesting aspects.
The first is that the ‘micro-channels- define the edges of the ‘paving stones’. The sediments resemble paving stones because as the region dried out the volume of the rock decreased and desiccation cracking took place. These cracks filled in (coarse particles, fines, berries). For a period the dunes moved. ( I have deliberately not called them ripples because they have ripples on them). At some point either the atmospheric density dropped below that needed to mobilise the armoured dunes, or the dune sand supply was depleted. Pick one because both in fact happened – a chicken and egg thing). So we have a pretty static environment with sediment blocks surrounded by dust filled moats. Probably a few had some cavities caused by continued desiccation shrinkage that the dust did not fill. So what would cause the fill to collapse causing the micro-channels.
Well the second thing from image 131 is that there are cobbles near both rocks with micro-channels. If these cobbles were (reasonably) recent impact events then that would have caused vibration of the rock and voila – collapse into the cavity creating a depression bordering the rock. Not as exciting as water gushing from below in defiance of the laws of physics, or Martian sandworms, but a lot more plausible.

Serpens, re your 142, Almost everyone (even me) imagines the dessication shrinkage of the layered rock and the latest movement of the big ripples as taking place in very widely separated periods of time. The mainstream puts the drying out of these sediments in the Noachian or Hesperian, at least several 100s of millions of years ago, more likely billions, but current thinking dates the latest big ripple movements to between just 100,000 and 300,000 years ago. Continued dessication of the bright rock during this very recent period seems unlikely to me. It is awfully hard to say though, given our ignorance of basic Martian processes. The Meridiani rock is presently hydrated and could possibly change hydration state and volume. Ice comes and goes in the near-subsurface over much of Mars, but we don't know if it could be near enough to the surface at Meridiani to cause cryo-turbation in the present era. During recent high spin-axis obliquity periods this might have been possible.

sol 2229 ( May 2, 2010 ) L257 2x1 ( HD format ) of rock in reply 139:

Looks like the rock is only a large block of eroded bedrock.

sol 2229 ( May 2, 2010) L456 1x3 vertical pan:

This shows Martian features from cm to 100+ km.

Serpens, Kye I think the mysterous part of the microchannels is that they must be very, very, very ( did I say very? ) recent.

Even the "small" dust storm Oppy endured a few years ago would completely cover one of these features. My best guess is these things are at most years old - not even decades.

Why the powers that be ( that, that - would not be me ) haven't looked closely at these features even once is an even deeper mystery.

Hort,

Those who think they, "know," have need to look and see. They can not understand what is true in and of there own Mind.

It's a rock, move on.

Fred

Here's a new view of the spot on Oppy's instrument deck. Seems like it has expanded. Sol 2229.

Couldn't find horts earlier images. Perhaps he could an animation.

> Not as exciting as water gushing from below in defiance of the laws of physics

Serpens: Surely upwelling water in a depression surrounded by a fluctuating water/ice table does not defy the laws of physics?

Winston: Really nice image of the "stain." It does look like it has increased in size, and now covers part of the solar panel, which I think it didn't before. It also seems more "raggedy" at the edges.

LWS, Thanks, I have learned to search Horton's stuff by clicking first on "hortonheardawho's photostream" above the thumbnail previews, and then searching with tags. In this case "sundial" worked well to find Horton's recent work on the deck stain beside the sundial.

Barsoomer, I can't see any clear change in extent since Horton first drew this to our attention but the stain might look more "raggedy at the edges" I agree. It has changed very slowly and progressively for hundreds of sols. It occurs to me, after viewing early images in Horton's library, that any change that made the dust thinner or more clumped into larger particles would produce greater transparency and might make the surface appear darker. Both the deck and solar panel were originally quite dark compared to their present overall condition.

Barsoomer; Re. the stain. Do you know if the area with the stain is within the work volume of the MI? if so, I'm wondering why they have not done an MI of the area yet.

Also, look at the huge amount of dust on the deck. Surely it sould have covered the stained area by now if that area was inert and unreactive. But it seems to be advancing along jagged edges suggesting a growth like movement.

Hope they provide these images on a fairly regular basis as Oppy roams along with some MIs.

Winston

link

Description of the IDD mobility system. The MI can image at least some targets on the rover including the dust-collecting magnets placed at the front of the rover near the base of the Pancam mast, and some calibration targets.

Personally, I kind of doubt that it can reach to where the stain is. Given all the images they seem to be taking of the stain with the pancam, I'm pretty sure they would have used the MI by now if it were possible.

link

Description of the IDD mobility system.

Anyone noticed anything strange about the accumulation of dust around curved stretches of wire on the Oppy panel? Remember strange could be that they might look exactly as we would expect them to look after months in the open in dusty terrain on earth.

Winston

LWS, re your 149, 152, The stain appears in images from sol 1785 and then slowly fades away by sol 1850 only to reappear covering a larger area on sol 2024. This is consistent with continuing growth in extent and the visibility of the stain varying with the degree of dust cover.

The significance of the "the accumulation of dust around curved stretches of wire on the Oppy panel" and in other locations sheltered from most wind, is that this is a great example of what the stain is not. Yes, dust does create thicker deposits in some places than others and those dirty crevices and inside corners make sense aerodynamically. The stain seems to be something else altogether in a relatively unprotected location now including some of the raised solar panel.

Kye;

My sentiments exactly

Winston

The stain sure seems to indicate an interesting process of some kind. If it is Life then of course it is super-interesting, but even an abiotic process that slowly grows across surfaces has got to be surprising. Has anyone come across any official scientific interest? I think that it is fair to say that hortonheardawho discovered the stain and so might be the first human to find extraterrestrial life.

I've always thought that if there is life on Mars some of it will be at the surface where the energy is and where materials - water and dust - are being moved around in large quantities by the atmosphere. The stain organism would have to have some capabilities beyond what any Earth organism has, but not of a fundamentally different kind. It would need to incorporate and store the nightly frost deliveries. It would need very good radiation protection. It would have to get solar-source redox chemical energy somehow, not necessarily from photosynthesis directly. The dust may return from the atmosphere photochemically energized, for example. I'm being deliberately vague to cast a "wide net". Our chances of guessing what strategies Life has come up with on Mars are slim.

Re the cracks...
Earlier findings that the infill 'rinds' appear to be vertically layered, suggest that repeated episodes of subterranean water-upwelling occurred. Thus it would seem that water was present in Meridian after the major surficial dessication had taken place (producing the cracks).

http://dls-website.com/images/WU_MarsRover.png

The sundial seems to be located near the rear of the rover deck. Perhaps something kicked up by the wheels is responsible for the stain?

This does not rule out a biological explanation. If it were fine soil, such as the dark fine soil near the outcrop edges, its persistence would still need some explanation.

Hmm.. This raises the question of why the dark fine soil near the outcrop edges doesn't get covered by the reddish dust.

Some interesting features in this stereo pair.

Barsoomer; Re. your #157. You might remember that sometime ago I posted the below sol 2161 image of the instrument deck with the stain and to me, very interestingly, right next to Oppy some pavement rock outcrops and a nearby muddy looking microchannel that looked almost exactly like the colour and consistency of the stain. The resemblance was fairly stark.

There were no comments.

perhaps if they explore deeper there might be some answers as to why the dark fine soil near the outcrop edges don't get covered in dust and usually are devoid of berries also.

Winston

Hi Barsoomer;

Another spot / stain on the instrument panel from sol 2219 images. Colour synthesized from the L2 and 7 filters. magnification x2.

Note the oily like appearance of the spots. Could they be related to the Horton stain? These spots look to me like darkened areas underneath a heavy layer of dust. The areas seem to be much darker than similar areas also covered with dust.

Winston