[meteorite-list] Alma College

From: mhutson at pdx.edu <mhutson_at_meteoritecentral.com>
Date: Mon, 28 Jun 2010 11:06:19 -0700
Message-ID: <20100628110619.20105vgpql34r5i3_at_webmail.pdx.edu>

Thank you for the link. This LPSC abstract reports specifically on
the results of experiments on 2 samples of pumice (terrestrial) and an
anhydrous basalt. It states elsewhere that earlier work was done on
other material including CM2 meteorites--the only one specified is
Murchison. One of the references refers to experiments on Allende
(CV3). Both of these meteorites were huge falls and there is
sufficient material in repositories for this sort of experimentation.
Discussion in this abstract regarding other carbonaceous chrondrites
refers to non-destructive measurements of porosity. In fact, the
abstract states "But the scarcity of the CI1 and Tagish Lake
meteorites has, thus far, precluded impact disruption experiments on
these very porous asteroid fragments", which is why they used
terrestrial pumice instead. I will also say that in my experience,
experiments on terrestrial analogs do not always give the same results
as the same experiments on lunar, martian, or asteroidal material.
This is an important area of research. Should someone spy an incoming
asteroid, there is going to be a rush to find out what to do about it.
  It is important to have sufficient data to make the correct
decision. Melinda


Quoting cdtucson at cox.net:

> Melinda,
> You might be right except that this article specifically states that
> they amazingly are referring to Carbonaceous chondrites
> when they say Pumice.
> Ed Majden sent me this link earlier;
>
> www.lpi.usra.edu/meetings/lpsc2010/pdf/1078.pdf
>
> It seems to me that there are plenty of Earth rocks that can be used
> to simulate these same results. Pumice just to name one that has
> even less value than those ugly NWA's. And these tests have and are
> being done using Earth rocks as well as man made materials. I saw a
> TV show on the Science channel where they were shooting into all
> sorts of different things for this exact same reason..
> Carl
> --
> Carl or Debbie Esparza
> Meteoritemax
>
>
> ---- mhutson at pdx.edu wrote:
>> Regarding Mr. Madjen's comment:
>>
>> "A quote from this article:
>>
>> "There are plenty of meteorites available that have little or no
>> value-------"
>>
>> If this is true, why do collectors pay big bucks for them? I wonder
>> what they do with the fragments! Just asking folks!"
>>
>> I have been interviewed by the press and seen comments in print that I
>> swear I never made. I suspect Dr. Strait was asked some sort of
>> question about how she could stand to break apart meteorites and she
>> said something along the lines of there are plenty of meteorites
>> available that have little or no scientific value and that would be a
>> true statement. I've seen thin sections of some heavily weathered
>> northwest African H5s and L6s that would add little to our scientific
>> knowledge of chondrites. Collectors do not pay big bucks for these
>> meteorites as far as I know. And as at least one sample was referred
>> to a pumice-like, it tells me that Dr. Strait was struggling to
>> explain what she was doing to a reporter that lacked the background
>> knowledge to actually understand what Dr. Strait was saying. That
>> sounds like a rough analogy that one uses to help someone understand
>> what you are talking about.
>>
>> As to what they do with the fragments, I don't know, but I suspect
>> that at least some are analyzed carefully to see how and why they
>> spalled off. That is the point of the experiment -- to understand how
>> to deal with an asteroid that is approaching Earth--what might work
>> for a large chunk of metal might be completely useless if the asteroid
>> is a C3 chondrite. It might even make a difference is you look at an
>> L3 vs. and L6 or a complicated breccia vs. a meteorite that appears
>> relatively uniform. Sooner or later we will spot an asteroid heading
>> straight towards the Earth with sufficient time to act upon that
>> information. It would be extremely useful to know what would be the
>> best way to prevent a catastrophe.
>>
>> Melinda Hutson
>>
>>
>>
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Received on Mon 28 Jun 2010 02:06:19 PM PDT