[meteorite-list] Alma College

From: Jamie Kimberley <jamie.kimberley_at_meteoritecentral.com>
Date: Mon, 28 Jun 2010 15:01:45 -0400 (EDT)
Message-ID: <alpine.OSX.2.00.1006281432460.184_at_ventoux.me.jhu.edu>

In general the specimens are significantly disrupted during the
experiment. Earlier work has looked at the particle fragment size
distributions generated under varying impact conditions. For sure
the fragments are collected and stored for later analysis.
For example:
Flynn, G. J., Durda, D. D., Sandel, L. E., Kreft, J. W., and Strait,
M. M., (2009). Dust production from the hypervelocity impact
disruption of the Murchison hydrous CM2 meteorite: Implications for
the disruption of hydrous asteroids and the production of
interplanetary dust. Planetary and Space Science, 57: 119--126.

If you do a lit search for G. Flynn you'll see a lot more tests on
meteorites and terrestrial analogs. As someone has pointed out it
is not clear how "good" our terrestrial analogs are. Testing actual
meteorite samples is one way to start. I personally work in
characterizing the strength of meteorites and other geological
materials. Some recent tests indicate that there may be some
significant differences in how meteoritic materials respond to
dynamic (e.g. impact) loading as compared to terrestrial samples.
Pardon the self promotion but this seems relevant to the current
discussion:
Kimberley, J., Ramesh, K. T., Barnouin, O. S., and Ernst, C.
M., (2010). Dynamic Strength Measurements of L5 Chondrite MacAlpine
Hills 88118. , 41st LSPC: 2588

http://www.lpi.usra.edu/meetings/lpsc2010/pdf/2588.pdf

Jamie

On Mon, 28 Jun 2010, MEM wrote:

> Most all of Tagish Lake( i.e. that which was not allowed to melt into the lake)--l which was recovered so to say, is easy to be had within the research community. While it is distasteful to collectors it is not much surprise for them to use it. TL, I would think, is more friable than pumice so I can see wy they would select it.
>
> I suspect the target pieces are almost completely pulverized. I'd not be surprised to know it is discarded since it is unsuitable for retargeting.
>
> Elton
>
>
>
>
>> 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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"You don't use science to show that you're right, you use science to
become right."--xkcd
__________________
Jamie Kimberley
Postdoctoral Fellow
Department of Mechanical Engineering
The Johns Hopkins University
Office: 410.516.5162
Mobile: 217.621.8272
Fax: 410.516.4316
E-Mail:jamie.kimberley at jhu.edu
Received on Mon 28 Jun 2010 03:01:45 PM PDT