MECA-OM Images - Page 22

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The Allan Hills meteorite ALH 84001, which is believed to have come from Mars, has orange grains about 100-200 microns in size. These have been identified as carbonate. Perhaps the similarly-sized orange grains in the OM images are also carbonate?

Hi Barsoomer

and the orange grains could be in the vicinity of 6-7% of the total particle volume captured on the the OM substrates. i.e. the percentage of carbonate suggested by the MECA / TEGA analyses.

Sounds like a good inference!

Winston

The orange grains may be an iron carbonate and some iron carbonates are magnetic. Some other iron containing minerals formed in sedimentary/evaporite rocks are also magnetic.

If you heat a magnet with a flame it will lose magnetism but some materials (like iron pyrite and olivene, I think) will become magnetic if heated. Some garnets are mildly magnetic as are some volcanic glasses. Pyroxene, augite, horneblende and other minerals are probably mildly magnetic and may be influenced by heat.

(I wonder if the continous high energy bombardment from solar radiation (years of sunny Mars days) has any effect on magnetism of the surface soils. There may be some minerals that have become magnetic due to ultraviolet bombardment).

There are many minerals that are magnetic on Earth. Magnetite is the most magnetic mineral commonly found on Earth. Magnetite commonly occurs with limonite and hematite. Limonite and hematite can form as a coating on magnetite. Hematite is magnetic and I think that limonite (a mixture of minerals) might also be magnetic.

Reply 420: Top image: Some of the clear colorless grains sticking to the magnets may have be quartz with a sliver of embedded magnetite (or other magnetic mineral).

http://www.gps.caltech.edu/~jkirschvink/pdfs/magnetofossils.pdf

Quote:

"Magnetite crystals in ALH84001 generally range from ;10 to 100 nm in size and have cuboid, teardrop, or irregular shapes (McKay et al., 1996). Magnetite crystals with these shapes are found throughout the ALH84001 carbonate globules in both the rims (Thomas-Keprta et al., 1998; 1999) and the interiors (Bradley et al., 1996; Thomas-Keprta et al., 199 , although they are most concentrated in the optically dark rims."

sol 143 OM montages here, including this one:

Looks like a broken tip has migrated to cell OM24.

The extensive cross contamination between sample cells weakens every conclusion about sampling location and soil type.

Who thunk up this flawed device?

It is clear that Phoenix should not be used as an example to teach how to engineer tools for Mars.

Sol 144 OM "'tween" images here, including this one:

If anyone is interested I will add the sample wheel positions.

Naaah.

Worm-like shape in this OM image.

Hi Barsoomer

Please point out where on image. So far I can't find it.

Winston

I guess it's just a smudge or moved chalk-mark. It is just over the top '3' mark. It looks like material from the ruled line has gotten displaced a little. Sorry for the post.

OM 145 montages here.

OM 146 montages here.

I wonder if the variation in the soil color is as, er, varied as it appears in my crude images.

Perhaps someday the official, color balanced and corrected images will be released and we can see for ourselves.

Perhaps the colors reflect some intrinsic property of the soil that varies with sample location and depth?

Regarding Barsoomer's replies 428 and 430, check out Horton's:

Looks like some kind of long thin thing in the indentation. Horton does such great stuff.

HH

This URL did not come through on my last post:

http://www.flickr.com/ photos/ hortonheardawho/ 2967965010/

Just remove the 3 blanks I inserted in the above URL

Thanks for the kudos Horace. I am happy when anyone gets anything out of the images.

I have mostly given up trying to draw attention to what I see.

For example, this is a detail in the montage referenced in reply 432 and 433:

I don't have a clue what this is clinging to the side of a "microbucket" sample cell.

Does anyone?

What force is preventing it from dislodging from the side of the spinning sample wheel and dropping into the chasm below?

What is the function of the spiraling rod? - the oval head?

What is the airspeed of a fully laden swallow?

Sol 148 OM montages here.

It looks like an attempt is being made to image the entire sample wheel.

Hi Hort

Now that's something you don't see everyday!

Winston

Hort,

If you stop calling attention this would be a slow forum indeed. The swirling tail and hopping rocks are part of this alien world. What can you say about an image like that?

Keep up the good work. If you stop what will Doug, Don and Stu have to do? Now back to watching the clouds and wind.

Fred

I wonder if single-celled organisms might tend to grow much larger on Mars, perhaps because of low gravity and maybe absence of multi-cellular life? How large is that item in Horton's image? About 10 microns?

Yes, how large is that object?
Maybe the scoop just dug into an ant hill!
Seriously that is an unusual object. We have not seen many mineral grains that are so rounded. Could it be a grain of volcanic glass or a small tectite?
It looks very organic but there are also inorganic possibilities. I would love to see more of them in the same shape/assemblage.

I have posted the full thing in the Carbonates thread perhaps the object in reply #434 could be related to this extract from the latest MRO finds:

"We see numerous outcrops of opal-like minerals, commonly in thin layers extending for very long distances around the rim of Valles Marineris and sometimes within the canyon system itself," said Ralph Milliken of Nasa's Jet Propulsion Laboratory (JPL) in Pasadena, California.

In some locations, CRISM observed opaline silica with iron sulfate minerals, either in or around dry river channels.

This suggests the acidic water remained on the Martian surface for an extended period of time. Dr Milliken and his colleagues think that in these areas, low-temperature acidic water was involved in forming the opal.

However, in areas where there is no clear evidence that the water was acidic, deposits may have formed under a wide range of conditions.

"What's important is that the longer liquid water existed on Mars, the longer the window during which Mars may have supported life," said Ralph Milliken.

"The opaline silica deposits would be good places to explore to assess the potential for habitability on Mars, especially in these younger terrains."

Link here:

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Perhaps this type?

http://en.wikipedia.org/wiki/Menilite