On the Road Again - volume 5 - Page 15

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LWS


Posts: 3062

Reply: 281



PostPosted: February 22, 2010 9:20 PM 

Serpens;

Could you point us to any papers that show categorically that berry stalks are composed of the same material that makes up the rock matrix? and also any MI images that show the berry stalks (not the wind tails)

Winston

Ben


Posts: 2270

Reply: 282



PostPosted: February 22, 2010 10:14 PM 

Winston; You may be interested in an article in the Mar.2010 issue of Sientific American that states "only a dozen minerals are known to exist among the ingredients that formed the solar system but today earth has more than 4400 species and more than half owe their existence to life".

RJS


Posts: 125

Reply: 283



PostPosted: February 22, 2010 10:35 PM 


A question for the Rock Guys that's been nagging me through this discussion about stems vs wind tails. Why is it only the berries have them? Why wouldn't small rocks, pebbles or other small/harder foreign objects around the berries also have stalks as well? Seems to me only the berries get them. Ben...?

Thx, RJS

LWS


Posts: 3062

Reply: 284



PostPosted: February 22, 2010 11:13 PM 

Hi Ben; Thanks! I read the teaser info on the article on the web and it looks really interesting. I don't have access to the full article (can't afford to pay for it)

Winston.

LWS


Posts: 3062

Reply: 285



PostPosted: February 22, 2010 11:23 PM 

RJS;

That's a truly excellent question, and one that might crystallize the whole debate. There are pebbles of roughly the same size as the berries but I have never seen a pebble with a stalk. Conversely all the berries I've seen with definite stalks are well shaped spherical ones. I will look at my images and see if I can find some showing pebbles with windtails or stalks. Purgatory will be a good place to look.

Winston

Barsoomer


Posts: 344

Reply: 286



PostPosted: February 22, 2010 11:39 PM 

Winston,

In your #280 image, there is a small piece of outcrop pavement near the center that has berries on it. It may also have a pebble, but I can't tell for sure. The berries appear to be associated with wind trails of some kind, but they look more like cone-shaped wakes than stems.

fred


Posts: 73

Reply: 287



PostPosted: February 23, 2010 7:01 AM 

If you look at the image in 202 you will see that the "Wind tails," are at all angles. That would mean that the wind was blowing in all directions with the same force. That is some majic wind. Not a chance brother.

Fred

Serpens


Posts: 169

Reply: 288



PostPosted: February 23, 2010 9:29 AM 

Ben believes that the initial berry formation was syndepositional. I think they are post depositional. On balance the evidence seems to favour post deposition but in any case we both believe that they are ultimately the product of a diagenetic process. Winston on the other hand suggests that that the berries and the fracture fill are biological, and even suggests that the rocks are akin to stromalites. While many images clearly show wind tails formed as an erosional process Winston rejects this on the premise that the berries on stalks are a different phenomena. The two positions could not be further apart.
Berries are extremely common both embedded in rock and as an erosional lag. But despite this prevalence berries on stalks are comparatively rare and in fact mostly seem to cluster around more recent small craters (ie Fram and Concepcion). Why? Possibly the ejecta stands proud of the surface creating a more favourable erosional aspect and in the current environment suspension rather than saltation provides a more gentle abrasive process.
Another significant consideration is that the berries are evident in both the cemented evaporates and in eolian sandstone. These two types of strata would have formed under significantly different conditions and the only commonality that I can see that would account for the presence of berries in both would be a groundwater recharge event.
The point on no evident clasts eroding out with tails is well made. But I think that we have only seen the stalks in the evaporative sequence and in these beds berries are common and can be attributed to diagenisis. Few clasts are evident. So given the huge number of embedded berries in the areas investigated, the very few embedded clasts seen and the comparatively rare incidence of berries on stalks I don't think that a lack of clasts weathering out with stalks is particularly surprising.

Bill Harris


Posts: 72

Reply: 289



PostPosted: February 23, 2010 10:03 AM 

I'm in agreement with your anaylsis, Serpens. Clearly a diagenetic process. My initial thoughts on the B'berries six years ago wsa "lapilli", but based onm their composition and occurence it became clear that they were concretions. And given that the stalks/windtails occur on freshly-exposed evaporite also clearly suggests that they are simply an aeolian-erosional phenomenon. There is no need to evoke complex spirits or gobblins.

This SE ejecta ray is a treasure trove.

--Bill

Kevin Author Profile Page



Posts: no

Reply: 290



PostPosted: February 23, 2010 10:18 AM 

Thanks Serpens, I wondered why there were so many around craters.

Could some or all of the salt in the ancient waters have been part of Berry formation?

Barsoomer


Posts: 344

Reply: 291



PostPosted: February 23, 2010 11:48 AM 

Serpens, I appreciate very much your posts, which are calm, reasoned, and treat other posters with respect even when you disagree with them.

I am still curious, however, about the "gentle abrasive process" creating the stalks as wind tails. Can you give any kind of constraint (lower bound or upper bound or rough estimate) on the amount of time in years that you think might be necessary to sculpt the wind-tails?

Do I understand you correctly that you think the reason why stalks are rare or non-existent at older craters is because a harsher erosion process has prevented them from forming? Any kind of estimate as to when the harser erosion era transitioned to the more gentle one?

Suppose for the moment that Ben's syndepositional idea is correct. Would you then consider "water tails" as a viable explanation for the stalks? Or might it at least create a more resistant framework for subsequent sculpting by aolian erosion? (I think Ben suggested something like this.)

LWS


Posts: 3062

Reply: 292



PostPosted: February 23, 2010 12:49 PM 

Serpens;

Re. your #288, I think that I should correct your impression of my position re. the berries, stalks, wind tails, impact melt, stromatalites, etc.

Its very simple. My position is based primarily on the assumption that Levin's Viking experiments demonstrated that microbial life exists now on the surface. That is the starting point.

If there is life on the surface then there is an even greater probability that life exists underground near the surface.

I assume that some water, even miniscule amounts, are necessary to sustain life in an active phase, even if it may not be absolutely necessary in a dormant phase.

The findings of significant underground water and that a water cycle exists on mars suggested to me that there is a possibility that below the surface microbes might exist in some unknown habitat.

The discussion on impact melt vs. fracture fill and the numerous images at Concepcion that showed crusts on rocks looking very much like lichen or bacterial mats suggested to me that they might indeed be fossilized bacterial mats.

That discussion and the unique images of the crust that likely enveloped several rocks suggested a model for microbes living beneath the surface in cracks and crevices in the rocks through which there might be a regular recharge of water and then rudely transported to the surface by the impact.

The images also suggested to me that the impact melt or fill might in several cases be composed of microbial mats whose growth was stimulated on the surface immediately after impact but that soon afterwards that growth was stopped by the harsh ambient conditions leaving what we see today as rock like "fill".

I suggest that the fill might be largely biological hence its significant degeneration and disappearance as compared with rock and true fracture fill.

Re the berries, I am somewhat ambiguous as to what they are. I think some are most likely concretions but I think there is a possibility that some might be stages of growth of some unknown microbe.

I think the wind tails are just that but that they are totally different to the stems. However, there are some wind tails that show up in a sinuous manner (several images from eagle to concepcion show this) primarily because they are covering "stem" material on the surface of the rock leading to the berries.

I think the stems are just that. They are different to the berries and they are different to the wind tails that might sometime enclose them.

I am tending towards rejecting the "impact melt" proposal for the crust if not fully accepting the "fracture fill" proposal.

I sent an email to Laura Kirkland and she responded quickly and graciously. The hematite found at Meridiani was indeed the fine variety but it was consolidated thereby providing a sop for both camps.

Barsoomer; This blog has gone a long way since the early days when people with way out views were targeted for fun by people like Bill. We've survived this and I think we can survive Bill's occasional lapses into his UMSF poster role of fraternizing with the natives. He has a lot to offer. I also appreciate Serpens who I can imagine feeling extremely frustated and annoyed at my posts but who always gives a civil response.

I like to think that my posts are just "thinking aloud" as ideas come to me. But I try to modify my ideas as new data comes to hand. Concepcion has provided lots of new data and ideas and I think we are just at the start of greater things to come. I eagerly look forward to the team revelations on the chemistry of the "impact melt".

Winston

Kye Goodwin


Posts: 1166

Reply: 293



PostPosted: February 23, 2010 1:51 PM 

RJS, re your 283, I think that your question is a really good one. Why haven't we seen any tails behind cobbles, for example?

For starters I'd like to point out a very consistent pattern that holds for all the layered sediments, bedrock or breccia that we have seen: There has never been an example of ANYTHING other than spherules apparently embedded in the bright rock. (I did have ONE example in my lost collections of cobble-tails at Duck Bay but the cobbles might well have been loose in that case. I'll try to find it.) There have been no indications in all the sectional views of layered rock that impacts created disruptions in the bedding during the long period assumed to be required for these sediments to be laid down. This is one big reason why I think that the sediments at Meridiani were not laid down over long periods of time but are catastrophic impact-surge sediments. Anyway, I'd say that we have seen no other particles forming wind-tails because spherules are the ONLY particles available. Why we don't regularly see wind-tails behind the billions of cobbles resting on bedrock is another mystery. I'm guessing that there has been no significant erosion of the bright bedrock since the cobbles arrived in their current locations.


I haven't thought it through but it occurs to me that there is no certainty that the bright rock erodes at a constant rate regardless of how long it has been exposed. Maybe Concepcion's eroded breccia eroded very quickly when first exposed. I like this idea because it proposes that the surface environment is not chemically the same as the environment just below the surface, leaving a role for Mars' climate to affect these highly water-soluble rocks. Maybe exposure slowly "hardens" the bright rock to further erosion.

hortonheardawho


Posts: 3465

Reply: 294



PostPosted: February 23, 2010 1:52 PM 

Here is a little puzzle. The dark feature behind the sundial has grown steadily since sol 2035 ( Oct 15, 2010 ) since it first appeared as a thin short line. Any ideas?

Here is an impossibility - according to the "wind tail" stem theory. If you look carefully you will note the short, thin "bluish" stalk in the center of the image. If "blue" = "hematite" = harder than the rock matrix then how could the wind create this feature?

I think this is the first image of a "naked" berry stem core and is intrinsic to whatever process that created the berries.

Kye Goodwin


Posts: 1166

Reply: 295



PostPosted: February 23, 2010 2:53 PM 

Horton, re your little puzzle linked in reply 294, WOW THANKS, I have no idea what that could be, WHICH IS A GOOD THING.

That patch of color sure is distinct. The rover has been moving and changing orientation so any sort of prevailing wind explanation is out. I have never known much about the rover technology, but I can't imagine how this could be leaking fluid or somehow originating from the rover, itself. This is a great mystery so far. It is simple, really demanding of an explanation. I hope I won't be disappointed when it gets explained.

LWS


Posts: 3062

Reply: 296



PostPosted: February 23, 2010 3:07 PM 

Hort; Re your #294. I know you don't want my ideas which are very predictable, you want the ideas of the rock guys that really matter, but, for what little its worth, I think its the inception stages of a microbial mat. Just watch that space near the sundial for the rest of Oppy's life and see how it develops.

Winston

hortonheardawho


Posts: 3465

Reply: 297



PostPosted: February 23, 2010 3:28 PM 

Winston, I very much want your ideas as well as the "rock guys" ideas. Here is a montage of views of the sundial from sol 2024 to 2157 that shows the development of the left side of the streak.

The saturated false color infrared view created from the 8 bit JPG data shows the streak as dark also.

The original 12 bit data probably resolves the puzzle to some mundane rock guy explanation. Sure would be nice if JPL commented on this feature. ( assuming that they know what it is. )

I think the "bluish" berry stem is actually more interesting as it is a "deal breaker" for the "stems as wind tails" hypothesis.

LWS


Posts: 3062

Reply: 298



PostPosted: February 23, 2010 3:39 PM 

Hort; Re your #294 again. Look at the area on the soil in the background with some disintegrating "crust". The blue stuff looks almost exactly like the "ooze" on the sundial. Is it possible to do a spectral analysis of the two areas?

Winston

LWS


Posts: 3062

Reply: 299



PostPosted: February 23, 2010 3:42 PM 

Oops I forgot to post my image of the dark spot on the soil. Its below

Winston

Barsoomer


Posts: 344

Reply: 300



PostPosted: February 23, 2010 3:58 PM 

Your #297 montage. The montage seems to show the enlargement occurred first at the edge of the platform. If it is a leak, it would be emanating from the platform on which the sundial rests. But what fluid could possibly leak that would be mobile under Martian conditions? The stain appears able to cross some of the boundaries on the rover deck.

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