Spirit discovered possible meteorites, and JPL's McMurdo Pan ... Options

[SigurRosFan]

... is online:

- View Northward from Spirit's Winter Roost

The rocks "Allan Hills" and "Zhong Shan" are possible meteorites.

<< They are the first likely meteorites found by Spirit.

Image of "Allan Hills" taken on Sol 809:


The rock in the center foreground of this picture is suspected of being an iron meteorite. The panoramic camera on NASA's Mars Exploration Rover Spirit took this image during the rover's 809th Martian day (April 12, 2006). The foreground rock, informally named "Allan Hills," and a similar rock called "Zhong Shan," just out of the field of view to the left, have a smoother texture and lighter tone than other rocks in the area.

The texture and glossiness of this pair reminded some members of the rover science team of a rock called "Heat Shield Rock," which was observed by Opportunity, Spirit's twin, in the Meridiani region of Mars more than a year ago. >>

[alan]

"Allan Hills," and a similar rock called "Zhong Shan," just out of the field of view to the left, have a smoother texture and lighter tone than other rocks in the area.

Wider view, I believe Zhong Shan is the smooth rock on the lower left.
http://marsrovers.jpl.nasa.gov/gallery/all...KMP2405L7M1.JPG
Zhong Shan may be the rock previously known as MizarKey's new favorite rock:
http://www.unmannedspaceflight.com/index.php?showtopic=2616

[PhilHorzempa]

For those who may not know, the famous aviation writer, Antoine de
Saint-Exupery, wrote about a similar encounter with meteorites in an African
desert. The following excerpt is from his book, "Wind, Sand and Stars,"
written in 1939.

http://wesjones.com/st-ex1.htm


It is found in Chapter 5 of that book, "The Plane and the Planet."
For those of you who love aviation and exploration, I recommend
this whole book.


Another Phil

[nprev]

Hmm...if true, it seems that reasonably pure iron & nickel is available in relative abundance on the surface for future use, to say nothing of carbonaceous meteorites with similarly useful constituents. Additionally, what does this imply about weathering rates on Mars in general (thinking that it's kinda slow right now...anyone have a ratio with respect to terrestrial erosional processes)?

[Guest_Richard Trigaux_*]

edited later: Ooops see next post by Cosmic Rocker before believing what follows

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again, I am afraid that some interpret a bit too much what they see.

Such vacuolar rocks are very usually basalt, more precisely pyroclastic basalt.

It seems that, on Mars, vacuoles are much larger than on Earth, due to the lower atmospheric pressure and lower gravity which allow for more expantion of the dissolved gasses. Add to this the perspective effect of Spirit's cameras, which make look things larger than they are.

So far as I know, they did not examined these rocks with the robotic arm, so sure they were of they composition. Perhaps there was an infrared imaging to make this identification more sure. If so, they would surely have spotted an iron block or any other unusual composition. And, if you remember well, this block was a member of a series of a dozen similar others, seemingly connected to the Homeplate structure.

Iron meteorites, like the one found by Oppy near the heatshield, have holes, but tunnels rather than vacuoles.

[CosmicRocker]

Richard: I think you might be confused by the description. The proposed meteorites are not the dark scoriaceous basalt blocks from the Spongebob family that are prominent in the photos. They are the light-colored, smoother textured ones closer to the bottom of the pictures. Look at the first image linked by Alan to see them both.

While they did not use any of the tools on the IDD on these rocks, they did use the mini-TES for corroborating evidence, as was mentioned in the original press release image caption.

"Observations of Allan Hills and Zhong Shan with Spirit's miniature thermal emission spectrometer indicate that they are very reflective, like Heat Shield Rock. They are the first likely meteorites found by Spirit."

[Shaka]

They are the light-colored, smoother textured ones closer to the bottom of the pictures.

For the first two meteorites of the Spirit mission to be both iron-rich and side-by-side seems to require that they are pieces of a single bolide that hit and shattered right here or overhead. Given that, there might well be other fragments around, and indeed, going by the false color appearance, there are a number of smaller candidates in the area.
I would hope there is time this winter to slap the IDD onto a couple, though I know there are plenty of them here on earth.

[Guest_Richard Trigaux_*]

Richard: I think you might be confused by the description. The proposed meteorites are not the dark scoriaceous basalt blocks from the Spongebob family that are prominent in the photos. They are the light-colored, smoother textured ones closer to the bottom of the pictures. Look at the first image linked by Alan to see them both.

Oooops Sorry I confused. The rock you speak about looks much more like an iron meteorite. We cannot be sure on the image but if I had the IDD and other instruments at hand I would try it before anything else.

It seems to be an incredible number or iron meteorites there!

[fredk]

A few more details in this New Scientist article.

[Phil Stooke]

There was a presentation at LPSC a few years ago by Phil Bland, British meteorite specialist, who predicted a certain size range of meteorites would be braked enough to land without destroying themselves but without burning up, given the density of the atmosphere of Mars. He expected people would find quite a few meteorites, if they could be identified. I'm not sure if anyone believed him.

Phil

[ljk4-1]

This is probably a long shot, but the rocks right at the base of
the Viking 2 lander look a bit meteoritish:

http://history.nasa.gov/SP-425/ch25.htm

Did they ever try to analyze them?

[Guest_AlexBlackwell_*]

This is probably a long shot, but the rocks right at the base of
the Viking 2 lander look a bit meteoritish:

http://history.nasa.gov/SP-425/ch25.htm

Did they ever try to analyze them?

How exactly could the Viking team have determined whether rocks were meteorites?

I guess one sure-fire way is that they could have, say, utilized the "Barry DiGregorio method" (i.e., hand-waving), who claimed that some of the rock vesicles at the Viking 2 site were "dissolution cavities" from "entombed fossils."

EDIT: DiGregorio also wrote this related story that was published at (where else) SpaceDaily. In fact, I remember actually reading the "fossils-at-Viking-2-landing-site article" he refers to in the story.

This post has been edited by AlexBlackwell: Jun 13 2006, 08:39 PM

[Bob Shaw]

This is probably a long shot, but the rocks right at the base of
the Viking 2 lander look a bit meteoritish:

http://history.nasa.gov/SP-425/ch25.htm

Did they ever try to analyze them?

Nope. Classic vesicular basalt. Look for spherical cavities, if present, it's basalt; if it looks like a lump of clay which somebody has attacked with their fingers, tearing out thumb-sized holes, it's a nickel-iron meteorite. Stoney meteorites (etc) would be much more difficult to identify, except by fusion crusts. Having said that, there are many meteorite hunters who have simply stumbled across the things on Earth, so on Mars, who knows?

Bob Shaw

[Stu]

It seems to be an incredible number or iron meteorites there!

One of my favourite scenes in the brilliant RED MARS is when a rover survey team encounters first a "strewn field" of meteorites, then a large iron meteorite, out on the surface of Mars... wish I could do that for real myself...

[alan]

color image of Zhong Shan (1MB)
http://marswatch.astro.cornell.edu/pancam_..._L257_pos_3.jpg