Mars Exploration Rovers Update - February 13, 2004

Doesnt solder tend to bead up on flux? Maybe there is a comparison there. Or as the martian atmosphere is different then here on earth maybe certain chemical reactions from heat-caused situations like crater exposions from incoming particles rocks etc would cause some of the elements melted in the explosion to `bead up` on the colder martian surface in a different atmosphere? Then wind distribution withsand could give it the mix as an earlier post suggests above. Sean

"sean" skrev i en meddelelse news: snipped-for-privacy@posting.google.com...

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I don't know - it could, I guess. My current problem is, that the outcrop judge by structure, is laid out in water: 1) the precipitation (being it biogen or not, of some sulfate-compound) in water would be very Earth-like ,

2) The lowangle bedding with onlap is an inherent fluid-structure but could be interpretated from wind-action. 3) The 'fused' or diagenetic appearance as an outcrop is very 'wet' and Earth-like. 4) Some of the spheres seems very fragile as probably could be expected for precipitations (gypsum CaSO4*2H2O wither to waterfree, possibly powdery anhydrite). I consider the biogen origin a possibility, but ascribe it to express but a subtle or vague 'livelihood' that may tilt a geochemical balance that under 'almost any circumstance' will be calculated from spontaneous geochemical equilibriums. Unfortunately we will probably not be exposed to very detailed mineralogical data, so our speculations will stay speculations. - Looking at an essentially dry Mars and argue 'wet' leaves a lot to be desired.

Not all observations of spheres conforms well to this 'wet' origin. Some backbone-geology on what traces flowing water and an accompanying hydrosphere would leave doesn't fit the picture. - So has Earth-bound geology come to a halt? Looking at the Mars-desert that could be any desert on Earth: No .... But most geological Earth-constants does not apply. What consequences for surface-geology follow from a crust that does not move continents around and does not renew itself and no longer disappears into the deep? That could very well make a lot of difference, along with all the other factors - especially including the perspective that these Earth-different processes has worked for a long time.... but that's obvious

The 'stabile' crust may after all also make some of the geology easier. Things are where they always have been: eroded sediments are put into the holes, - and stay there. A deep sea or lake does not stay deep for a very long time. And no orogens re-expose the sediment. What would this mean for the traces we expect to be left by water? The large-scale morphologic traces of water all conforms to one thing: There is an overwhelmingly lot more sediment to be carried, than water to carry it. - maybe a natural consequence of a retreating hydrosphere.

I wish that I right away could account for the wave-climate in a shallow lake under the given circumstances, but I cannot - but I have reason not to expect a very choppy and energetic seasurf. If the sediment-sink is off and 'too much' is standard, - what would be the consequence? Evaporites, but also heterolites, that is an inter-layering of sand and clay - or straight out laminated strata. Such an occurrence - and that's not much to ask - could definitely point to a 'wet' origin.

If a hydrosphere 'on the edge' has been a standard, and a shower an ultimate climatic anomaly - then I could see the raindrops in turbulence aggregate dust to form spherulites - or raindrops preferentially nucleate around dust-particles.

Carsten

I don't know how fragile they are, as they seemed towithstand crushing by the instrumentioan package, and they appear to weather better than the outcrop does.

Why do you think that to be the case. Geez, the rovers have only been up there about five weeks or so, and everyone is already complaining that the data is not being disseminated fast enough. Put away the conspiracy theories. These guys are working very hard, ok?

Fluid structures are very common in lava flows-- both pahoehoe basaltic and rhyolitic welded ashfall/ashflow tuffs. The Hawaii geos probably know much more about this than I do, but there is an entire subfield called vulcanospeleology, which is the study of speleothems and speleogens associated with above water lava tubes and flows. Whether this is associated with volcanoes, impact or caldera collapse on Mars, I don't know. Since water vapor and steam fumaroles are associated with volcanic explosion and caldera collapse, could it not be possible that the water vapor existed at the time of rock formation, and then escaped Mars?

Ashfall/ashflow can be either primary or secondary--while the ash only falls once, it can weld and slide at that time, or later, after being reheated due to subsequent eruptions. Sure, streams can be involved, but they needn't be permanent water. An analogy would be the mass wasting and movement caused by flooding of a usually dry area. A 'gullywasher' so to speak.

All this talk of Martian wind, and even atmosphere is a bit much to fathom, since the gas density is much less than ours. Although I know Martian 'windstorms' exist, wouldn't they be pale imitations of those on earth, with consequently less ability for mass transport?

I know. More questions than answers...

Pale imitations or not, Mars shows wind-blown sand dunes and dune fields considerably larger than anything comparable on earth. That little wind and that lower gravity and those millions of years all conspire to produce some pretty collossal structures.

Thanks. Wonder how wind velocity at lower density and gravity can move particles which are also at the lower gravity. Hey, I do rocks and water, and leave the atmosphere to someone else. I have no need to be omniscient.

The answer is in Bagnold's "fluid threshold" equation:

Vc = a*sqrt(k*g*D)

Where: Vc = critical wind velocity to lift a particle is then a = empirical constant g = acceleration of gravity D = particle diameter

k = (rhoP - rhoA)/rhoA

rhoP = density of particle rhoA = density of air

A particle might have a density of 2.73 g/cm^3 (rhoP) which would be much greater than rhoA for either Earth or Mars, so k would simplify to approximately rhoP/rhoA. Since Mars has say 1/100th of the density of Earth's air, k will therefore go up on Mars by a factor of 100. On the other hand g is 3 times less than on Earth, so k*g*D only goes up by a factor of

1. The square root of that means that Vc would be 5-6 times greater on Mars than on Earth.

Not quite as bad as one might think.

Joe

And few obstructions, such as trees.

I guess that my point is, that the current stock of water on Mars might suffice for a few climate-extremes to produce wadies and gullies - but not enough to form a free-flowing body of water. The point does not necessarily need a dramatic escape of water out of Mars either.

A hot and welded ash is not obvious and probably lacks other traces of it's being - like the free-flowing water scenario leaves a lot to be desired. But how much of a volcanologist am I?

Something like that. My focus would be on 'what would rain from the sky?'. The first steps in an active hydrosphere is clouds. You know that I have anticipated a lot of dust or clay-size sediment as a consequence of prolonged erosion if a drain for the dust is missing. So basically I see the spheres as the drain. I'm not too much of a meteorologist to know of what to anticipate from the combination of dust and clouds - but I can come up with some speculations. Since we have seen clouds, my idea may not be too far off, and may not necessarily include too dramatic changes from the present situation.

The exposure may be an anomely - related to an extreme climatic situation, like what could have formed the gullies. It is not evenly distributed but this could be induced by both wet or dry dunes - I favour the dry dune for these speculations. The exposure expresses a chemical seggregation .. it does not seem to constitude an average reed 'dust'. I would see such a seggregation possible in the free atmospheric flow of dustparticles (also constituting salts and other evaporites), icecrystals and droplets. This flow could be prolonged in time. And I cannot dismiss the idea that the wet aerial aggregations could evaporate it's watercontents to form perfectly spheric aggregates at the time of hitting the ground.

I think that Curtis provides information that generally enhances the posibillity of 'coalesence' of finegrained particles. The armour of hydroxides that limits chemical weathering on Earth -if attributed to H-bonding to broken bonds - could be exchanged by availability of more H-rich compounds that may become H-bond 'bridges' between particles with positive broken bonds (like the silicates).

If I serve my teachers credit, I would be able to - from the low angle onlap - to express something decent on the depositional environment. Sorry teachers. But I most certainly know what I would be looking for the next time I get around such information. (Thanks for Bagnold's, Joe). As an expression of windblown sediment I could 'see' thin sheets (light density, non-cohesive) pushed around by the wind and falling at rest with a low-angle discordant onlap.

I did it again - pulled an impressive speculation-stunt. Don't be fooled.

Carsten

necessarily

Mars has clouds, just not to the extent that it would make a difference.

Since the crater is the only area in the region that we've explored thus far, we don't know the extent of the bedrock.

We don't know that either.

?

Or before.

Yet it cannot be ignored. If there is one thing that has been learned in the exploration of Mars, it is that the Martian wind and its dust storms play a significant role in shaping the landscape of the planet.

Not really. Our dust storms are never globally encompassing, like we see with the Martian storms. Martian dust storms not only often encompass the entire planet, they often last for many months.

Hibernating Martian life between droughts.

Sons and daughters of "the blob"? Oh, nevermind.

Petrified gulls' eggs?

On that score the naturalist and explorer Samuel Clemens had some interesting observations about life in a briny lake near the town of Mono, California, in his book "Roughing It":

Mono Lake lies in a lifeless, treeless, hideous desert, eight thousand feet above the level of the sea, and is guarded by mountains two thousand feet higher, whose summits are always clothed in clouds. This solemn, silent, sail-less sea--this lonely tenant of the loneliest spot on earth--is little graced with the picturesque. It is an unpretending expanse of grayish water, about a hundred miles in circumference, with two islands in its centre, mere upheavals of rent and scorched and blistered lava, snowed over with gray banks and drifts of pumice-stone and ashes, the winding sheet of the dead volcano, whose vast crater the lake has seized upon and occupied.

...

The lake is two hundred feet deep, and its sluggish waters are so strong with alkali that if you only dip the most hopelessly soiled garment into them once or twice, and wring it out, it will be found as clean as if it had been through the ablest of washerwomen's hands.

...

There are no fish in Mono Lake--no frogs, no snakes, no polliwigs--nothing, in fact, that goes to make life desirable. Millions of wild ducks and sea-gulls swim about the surface, but no living thing exists under the surface, except a white feathery sort of worm, one half an inch long, which looks like a bit of white thread frayed out at the sides. If you dip up a gallon of water, you will get about fifteen thousand of these. They give to the water a sort of grayish-white appearance. Then there is a fly, which looks something like our house fly. These settle on the beach to eat the worms that wash ashore--and any time, you can see there a belt of flies an inch deep and six feet wide, and this belt extends clear around the lake--a belt of flies one hundred miles long.

If you throw a stone among them, they swarm up so thick that they look dense, like a cloud. You can hold them under water as long as you please--they do not mind it--they are only proud of it. When you let them go, they pop up to the surface as dry as a patent office report, and walk off as unconcernedly as if they had been educated especially with a view to affording instructive entertainment to man in that particular way.

...

Mono Lake is a hundred miles in a straight line from the ocean--and between it and the ocean are one or two ranges of mountains--yet thousands of sea-gulls go there every season to lay their eggs and rear their young. One would as soon expect to find sea-gulls in Kansas.

...

Half a dozen little mountain brooks flow into Mono Lake, but not a stream of any kind flows out of it. It neither rises nor falls, apparently, and what it does with its surplus water is a dark and bloody mystery.

...

In speaking of the peculiarities of Mono Lake, I ought to have mentioned that at intervals all around its shores stand picturesque turret-looking masses and clusters of a whitish, coarse-grained rock that resembles inferior mortar dried hard; and if one breaks off fragments of this rock he will find perfectly shaped and thoroughly petrified gulls' eggs deeply imbedded in the mass. How did they get there? I simply state the fact--for it is a fact--and leave the geological reader to crack the nut at his leisure and solve the problem after his own fashion.

Project Gutenberg e-text:

I am an interested amateur only, so some of your terminology terms elude me here. But your post is interesting an informative thanks.Regarding your last idea of raindrops maybe from a severe and infrequent storm rather than persistent earth like rainfall ? Although one problem I thought was if it was rainfall it would have to be a warm environment and the current climate is way to cold for a liquid water to fall as rain. Anyways ifthe climate was warm enough and if the nodules are composed of a material that fuses like a fast drying cement one could possibly recreate soemthing similar here in a lab. Is there a gas that liquifies at the present mars temp that could fall as rain to replace the water part of this precipitate theory?

Otherwise in a dry scenario If the nodules are on the surface maybe they were created more recently rather than be sediments from wind action that have since been disturbed. Going back to the explosion idea I suggested before,.. I dont know if there are enough craters to allow the statistical chance of finding these all over Mars and at the lander site but I was thinking a bit more on maybe how they were created, if by an impact crater event. If lets say at impact either water or another gas either present as liquid or solid in the projectile or in the sediment ,were to be instantly heated to extreme high tempratures. The material that the nodules is made of could also mix in that instance with that breif extremely hot gas cloud above the explosion site sort of like a soupy particulate mix of gas and liquid droplets mixed with the nodule element. As it is forced out and away from the site at great speeds by the explosion the mixture is cooled rapidly as it spreads out into the presumabley extreme cold of the martian atmosphere. This would cause the cloud to precipitate out in a sense into droplets , all small , and very rapidly `freeze` into shape in seconds as they are speeding through the extreme sub zero martian atmosphere and then presumably are hard all consistently sized small frozen droplets when they land around the impact site. They then over time `freeze dry` out the liquid water (or whatever liquid it is) in the sun and climate to the present state of a nodule consisting of just the original material which could have initialy pre impact have been a powder or granular material like glass once was sand? One idea would be to look for similar phenomena at old nuclear test sites as in essense I am suggesting they a sandy or powdery medium mixed in with a liquid and as baked `nodules in extreme rapid heating , cooling and speeding `event` through a cold atmosphere to get the small sized droplet shape. Maybe the thinner matian atmospher would aerodynamically produce a rounder projectile rather than the heavier earth atmosphere which would have elongated the droplets .As I mentioned this phenomena may also occur similarly at nuclear test sites. They then erode by wind into the observed sandy mixture Sean

"sean" skrev i en meddelelse news: snipped-for-privacy@posting.google.com...

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What conserns Mars, I'm a newbe too

No, CO2 does not have a liquid fase in the surface temperature/pressure range. So any application of the idea would take a climatic anomaly away from the present cold situation.

It's not advisable to do what I did - refere to an instance without a linked picture. Because the spheres are widespread and have what what seem like multiple modes or origins - and it confuses the discussion.

This is a detail of the outcrop I refer to

I'm a little blank on that

I figure that to be the general expectations

Some seems fragile (atleas to me) others seems to be melted rock - it would be tempting to unite such a diversity in an impact-event.

They are observed in diverse places and seems to me to have been produced in a widespread process and incooperated by different sedimentary processes. There is a lot of parameters on Mars that differs from Earth - and I think that most find it surprisingly confusing to puzzle the consequences together when the desert-surface from a distance afterall looks very Earth-like. I have in another post tried to let meteorological phenomena be responsible, but most of the spheres seems too large (to mention one thing) to give such an idea much credit. Geochemical considerations may very well hide clues - pressure, temperature, constituents and complexity should be sufficient to keep everyone at a distance from even speculating or predicting.

It' a challenging problem.

Carsten

I've just looked at the Sol 27 panoramics for Opportunity, and it is very clear to me that these are indeed sedimentary rocks. A simple explanation would be that the spheres are the fossils of some simple organism, that upon dying, would drop to the bottom and be buried in the same manner that fossils here on Earth can be trapped in layers of sediment. You can clearly see that the spheres are trapped in the layers, and that they are eroding out. The least hypothesis is that the spheres were deposited in the layers as the layers were forming. They are more durable than the layers themselves, which is easy to see in the weathering images from the microscope. Furthermore, the spheres themselves show some characteristics that are otherwise extremely difficult to explain using standard geological processes. As a long time amateur rockhound, I have seen and collected many specimens, both abiotic and fossils. I could easily understand a sphere with consistent layering throughout, but not many spheres with similar markings such as parallel grooves or chevrons. I have compiled the microscopic images and performed some contrast and image processing to extract features that are otherwise faint or difficult to discern, and there are definitely common features on many of the spheres. In my (perhaps flawed but experienced) opinion, we are seeing fossils. There, it's been said. I have a good reason to take this position- in 1992, I wrote an article about the possibility of life on Mars (which was published in Astrolog magazine), and used some of the reasoning of Thomas Gold about petroleum formation and organisms that metabolize petroleum. In it, I predicted that organisms could still be extant in the rock of Mars if it consumed petroleum as many such organisms here on Earth do. Also, I predicted that in that case, we should look for fine grained magnetite, which is a metabolic byproduct of the digestion process of those sorts of organisms. This was four years before the flap about ALH84001 (1996) so in a sense I beat them to press with at least two good predictions that matched what they found. At this point, I am very encouraged by what we are seeing that life did indeed exist on Mars, and that if we were to bore deeply into the rocks where petroleum might exist, we would discover that deep inside the planet, there are still organisms that are alive and well. After all, a loss of atmosphere here on Earth would not destroy those organisms that live within the rock. I intend to post these processed images on my website shortly, as this is a very interesting development and it is good, reasonable support for this idea. Once again, I am not a geologist, but I am a scientist and have been a rock collector for about 40 years. My opinions could be completely wrong, but I believe that Opportunity has succeeded in finding remnants of extinct Martian organisms.

Cheers!

Chip Shults

I now have proof that these spherules are fossils very similar to tiny crustaceans, similar to tadpole shrimp or trilobites. I have a paper in submission for publication documenting the method I used for locating the data. These are absolutely fossils, no doubt about it.

Cheers!

Chip Shults

Feel free to share those methods with US on the usenet.

Proof is mathematical, science is demonstrative.

Besides, Jonathan has already clearly identified the spherules as the gemmules of a microbial sponge colony : 'porifera jonathanii'.

Nice try, though. Keep up the good work!

Thomas Lee Elifritz

Has a ring to it~

If this pic doesn't show imprints of skeletal spicules, I don't know what else can!

Jonathan

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