Mars Exploration Rovers Update - February 13, 2004



check
hematite
environment
Gee Carla, where did you get that information? Even the JPL scientists have said that they have had trouble taking readings from the spherules ecause of their small size. They haven't said what they are composed of. In addition, there is no reason to assume that the spheres are only sitting on top of the soil. Let's wait until they conduct the trenching and report on their analytical results before we all make such pronouncements, shall we?

Actually if you look at the picture at the following link. you will see small dunes in the foreground. Since the rover has yet ot even leave the crater, nad since the dunes you refer to at Gustev crater are ver small, I see no reason to expect that these dunes will not be found at the opportunity site as well.

beeing
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George wrote:

Did you see the colored map of hematit concentration ? No hematite where the airbacks compressed the soil, that means the spheres have been pressed below the dust and the spheres are the carrier of hematite mineral.

It was a guess, I wanted to file here. So if I am right I will be able to say I knew it in advance.

???
Lets see. usually a crater should be a place to expect such dunes if there are any. There are no dunes visible that bury the spheres.

--
http://www.geocities.com/carla_sch/index.html

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its
and
the
wheels
for
have
ecause of

on
Yes the spheres were pressed below the soil surface. That does not necessarily mean that the hematite originated from the spheres. Why? Also note that the uppermost topsoil itself was disturbed. In addition, and spectral analysis of the rock outcrop from which the spheres apparently orginated was very low in hematite.

we?
I can understand that sentiment. However, I'd be careful about making statements prematurely. The often times have a habit of coming back to haunt you.

Oops, sorry. Here is the link.
http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040214a/hem_strip1.jpg
Download the image, then open it in the image processing software of your choice (I use Adobe Photoshop, and Corel PhotoPaint). Zoom in on the far right-hand side of the image,and you will see small dunes. You will also note that the soil appears to be thicker in this area. Also note that not only is the soil disturbed by the airbags low in hematite, but a large area of undisturbed soil from the center to the right of center in the image also is low in hematite. So I would have to say that in my opinion the areas where the hematite is highest in concentration must have some other unique feature that is allowing the hematite to be concentrated there.

the
I
As appears to be the case with this crater, it seems that the wind blows the strongest in the area where the outcrop is exposed - since it has been denuded of its soil, I would think this would be likely. Where the wind speed drops, one would expect it to drop its load of sediment. One would expect to find dunes only near the top of the crater away from the outcrop. Low and behold, there are dunes in the right-hand side of the image shown in the link, above, at the top of the crater. I would expect that soil comprising these dunes may have originated from the exposed area of outcrop. Whether these dunes have buried any spheres or not is unknown since they have not taken the rover over to that area to investigate.

from
they
dust
Interesting web site. Of course, it has nothing to do with this newsgroup, or the subject of this thread.
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The relative cross-section of the spherules in the matrix facing the camera is about 2%. They are much more concentrated on the ground, particularly in oblique views.
The spherules tend to come out bluish when visible RGB images are combined, leading to the moniker "blueberries.: It's interesting to compare such a composite to the hematite map produced by the TES.
http://www.copperas.com/astro/spheres_hem.jpg
The more red areas in the right image (hematite) tend to correspond to the more blue areas in the left image (spherules). Conclusion: spherules hematite.

Now what fun would that be?
Joe
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wrote

Also
camera
in
combined,
It has been my understanding from reading the interviews of the project scientists that they were referred to as blueberries because of their shape and size, not because of their color. In addition, there is no way that you can look at the picture you posted above and say that the blue color is due to the spherules simply because you cannot even see then at that resolution. On the other hand, you can look at this image and get a clearer view of the color of the spherules.
http://www.jpl.nasa.gov/mer2004/rover-images/feb-04-2004/mib_color1_quasinatural-med.jpg

Here is a link to the TES data collected by the rover:
http://www.jpl.nasa.gov/mer2004/rover-images/feb-14-2004/hem_strip-med.jpg
The data is superimposed onto the panorama of the outcrop and edge of the crater. If you will note that in the center of the image is the area of the outcrop first examined by the rover. That area had a lot of spherules on the ground around the outcrop (the outcrop referred to as "stone mountain"), within the outcrop itself, and below and above it. Note that this area is hematite-poor. And the outcrop itself was hematite-poor. For verification, please note this image of the area I'm referring to:
http://www.jpl.nasa.gov/mer2004/rover-images/feb-09-2004/MI_Context-med.jpg
http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040211a/Waypoints_Outreach1_br.jpg
You should also note that there are very few images sent back by opportunity of the soil in which the spherules were not present, yet there are large areas that appear to be hematite-poor. As I've said before, I think is it too early to say that the spherules are composed of hematite. Looking at data brought back from Apollo 14, similar granular spherules were found at that site that turned out to be composed largely of plagioclase. I think I will wait for more data before reaching a firm conclusion regarding the spherules.

shall
Well, we can all speculate all we want to, but my experience with speculation is this: Don't assume, that way you won't make a fool out of you and me! :-))
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shape
Mark Lemmon: "We've looked at the floor of the crater itself and it's exciting. In particular, this area is covered by finescale sandgrains and these irregular grains coming down from the outcrop potentially and the most spectacular are these rounded spherules being called blueberries because they're relatively bluer than their surroundings." (Thursday, Feb. 12)
If you miss them, a lot of the press conferences are archived on C-SPAN; unfortunately they don't have that one though.

due
resolution.
But you can see the blue color at that resolution, which the blueberries are in such an RGB composite (with overemphasized blue).

the
http://www.jpl.nasa.gov/mer2004/rover-images/feb-04-2004/mib_color1_quasinatural-med.jpg
Officially they are calling the color of the spherules "gray." Or at least grayer than the matrix. Gray hematite anyone?

the
mountain"),
verification,
http://www.jpl.nasa.gov/mer2004/rover-images/feb-09-2004/MI_Context-med.jpg
http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040211a/Waypoints_Outreach1_br.jpg
However, speaking of resolution, this is the area of the "hematite strip" you are basing your conslusion on:
http://www.copperas.com/astro/hemstrip.jpg
The approximate area of your Stone Mountain closeup is indicated.

opportunity
Not really, outside the airbag bouncemarks:
http://www.copperas.com/astro/hematite.jpg

I
Similar? They were over ten times smaller than these and were made of dark glass!

But is speculation, particularly based on current data, equivalent to assumption?
Joe
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wrote>

most
are
http://www.jpl.nasa.gov/mer2004/rover-images/feb-04-2004/mib_color1_quasinatural-med.jpg
Plagioclase can have a blue-gray tint as well, and is commonly found in spherules of impact origin. Let's wait for the TES analysis shall we (if they ever are able to analyze the spherules at all) before we start giving them a mineralogical association? Agreed.

http://www.jpl.nasa.gov/mer2004/rover-images/feb-14-2004/hem_strip-med.jpg
the
on
is
http://www.jpl.nasa.gov/mer2004/rover-images/feb-09-2004/MI_Context-med.jpg
http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040211a/Waypoints_Outreach1_br.jpg
Yes that is it.

Take a closer look at the image with the TES analysis archs. Large areas covered by the archs are hematite-poor:
http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040214a/hem_strip1.jpg

at
at
think
Not at the Apllo 14 site. The were much more coarse-grained, and were larger than ones found elsewhere:
http://216.239.51.104/search?q che:2iTagxgH__IJ:www.lpi.usra.edu/meetings/lpsc97/pdf/1480.PDF+formation+of+granular+spherules&hl=en&ie=UTF-8
The spherules found at the Apollo14 site, and at Opportunity are close to the same size (no larger than a few milimeters). The spherules at the Opportunity site are smaller than you must think they are. Note that rocks at the Apollo 14 site were similar to the bulk composition that appears to be seen at the Opportunity site: That is there is lots of olivine, which indicates that there is a basaltic source rock somewhere in the vicinity. The plagioclase at the Apollo 14 site no doubt originated from the basaltic rocks in which the craters in the region were formed.

of
As long as you make clear that you are speculating or making asumptions, you are probably going to be fine. It is when you make lots of assumptions and then make definite conclusions based on them that you and I get in trouble. Am I wrong?
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http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040214a/hem_strip1.jpg
The beam width is very narrow, so it doesn't cover a large area. To say that large areas are hematite poor is inconsistent with their other hematite map. Also note that the strip such as it is registers positive right about where it goes under Stone Mountain.

dark
http://216.239.51.104/search?q che:2iTagxgH__IJ:www.lpi.usra.edu/meetings/lpsc97/pdf/1480.PDF+formation+of+granular+spherules&hl=en&ie=UTF-8
That formatting is hard to follow. This is what I have re Apollo 14 spherules:
"These 155 lunar spherules ranged in size from less than 100 microns to more than 250 microns, and came from lunar soil picked up in 1971 by the Apollo 14 mission crew near Mare Imbrium (Sea of Rains), the dark crater that dominates the moon's face. Statistical and chemical analyses showed that the spherules studied came from approximately 146 different craters."

The Meridiani spherules are on the order of 3 mm (3000 microns). That is, over ten times bigger than the Apollo 14 sample.

See above.
Joe
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wrote

areas
http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040214a/hem_strip1.jpg
You are correct, it doesn't. However, because it made an arch across the area in question, I think it is safe to say that the analysis it made is representative of the area as a whole.

map.
where
No, what it registers is slightly (green) more than none (blue), and that is below the rock, not on the rock.

http://216.239.51.104/search?q che:2iTagxgH__IJ:www.lpi.usra.edu/meetings/lpsc97/pdf/1480.PDF+formation+of+granular+spherules&hl=en&ie=UTF-8
more
the
to
Ok, you convinced me on the size issue.. I went back and re-read the article, and was mistaken about what they said the size was. According to the article, and another one
http://tinyurl.com/2uf7m
they ranged between 40-500 m, with 200 m being common. Also, in relation to the general makeup of the site, the spectrum of the landing site indicates, in order of abundance, olivine, Fe2+ (silicate phase), Fe3+ (phases), and finally a very small magnetic mineral phase (probably magnetite). The fact that the most abundant iron phase is a silicate phase is interesting for several reasons. If I am reading it right, the fact that the spectrometer can discern between olivine and other iron-bearing minerals tells me that you can exlude that as one of the iron-bearing Fe2+ silicates. Fe2+ silicate possibilities include andradite, and various pyroxenes (ferrosilite?) and amphiboles, and others. Interestingly, Actinolite and the amphiboles require water to form. An interesting aside to that is that no amphiboles were ever found in samples brought back from the moon.
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FWIW, here is a great montage Doug Ellison made of part of the outcrop, with the blueberries resplendent & some idea of the variation.
http://mer.rlproject.com/index.php?act=Attach&type=post&id 1 (warning: big file)
Joe
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wrote

with
(warning:
Thank you for that link. That is quite a good montage. I must say that it is quite annoying that JPL doesn't post these images in final form on their web site. I guess my problem all along has been to rely on the spottiness of their color image posts. And the fact that never having had to do the colorizing myself also makes matters worse. It was only recently that I even figured out how to do this, so thanks to whoever posted that information. Having said that, I find the color of the outcrop to be very intriquing, as it looks just like some rhyolites I've seen in the field in the Western U.S. That doesn't mean that I think the rock IS rhyolite, hoever, as I've never heard of rhyolites with concentration of sulfure that this rock has. What software are they using to generate the color images? I have several that could possibly be used (Corel PhotoPaint, Adobe Photoshop, Corel Painter 8, Picture Window Pro, and Astrovideo,which is great for processing black and white CCD astro photos into color using color filters). Unfortunately, the art of colorizing is fairly new to me. By the way, don't be stingy about posting links to great pics such as this one. Since JPL isn't posting many color-processed images directly into their web site, People like me are scarmbling to find them.
another annoyance is that they don't post higher resolution images. The Mars Express site is posting images at 300 and 400 dpi, while we have to rely on 72 and 96 dpi images. Screw the file size: I have adsl! I want HIGH resolution! The larger, the better.
Again, thanks.
As an aside commentary, I find the purplish "reaction"? discoloration on the rocks where there are "berries embedded in them very interesting, indeed. Any comments on them?
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Has the possibility of the spherules being wind rolled and rounded pebbles been discussed?
The spherules could then have been recemented into layers by periodic ash falls. If the spheres tend to concentrate on the paleo surface, this would explain the apparent layering and close packing of these abundant little things. It may also explain the sorting into remarkably consistent sizes since like sizes would be deposited in similar places.
Doesn't Mars have strong enough winds to move pebbles like the spherules easily?
- Graham Parkinson

it
their
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Well, that is always a possibility. However, that idea has to take into account the material that would have accreted to the surface of the Spherule, in this case, whatever soil it rolled over. In this case, the spherules are granular, and appear to be fairly uniform in compostion, as indicated by the high resolution imagery. I've even seen crystals on the surface. Unfortunately I can't obtain a high enough resolution image to make out the crystallographic details of the spherules. All I can tell is that they appear to be either orthrombic or tetragonal, based on the apparent rectancular (trapezoidal) shape.

would
Its always possible that high winds could come along and move them around. Otherwise they wouldn't be distributed all over the place.
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I don't think that a similar process occur naturally on Earth. If it should be shaped by rolling on the surface, it would have to be quite light and could also be expected to form their own windblown deposits - tumbling and abration of rocks in the sea-surf tend to make oval and flat rocks. But I do believe that artificial processes like burning wet cement and fertilizer in rotary-ovens tend to make somewhat rounded aggregates. The distribution of the spheres does not seem to me to follow some basic erosional rule (if looked upon as having an average density): to compose a welldefined lag-sediment (* see below), but seems almost randomly sprayed out - but I could be fooled by low-density spheres following wind-dynamic like smaller grains. I believe that some sediments may have two or more grainsize populations ... the second fitting the interstices of the first, but that does not seem obvious to apply on current observations. A 'random' distribution may conform well to an 'ordinary' event like a spray from an impact.

would
There is a lot of critical comments to add to this, but I'll stick to one: recementation needs replenishment of water.
snip
(*) The Spirit site achually shows a fair lag-sediment of tightly packed round 'pebbles' with finer sediment in the interstices. If this can be considered an eqvilibrium in current erosional environment, other observations may not yet have reached such 'maturity'
Carsten
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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
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snip

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
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,
could
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.

a
under
detailed
at
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?

desert
the
obvious
There
to
and
ultimate
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Carsten Troelsgaard wrote:

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...
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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.
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Chosp wrote:

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.
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