Carl mentioned "a CK parent body." I doubt that there is such a thing. In
a recent paper, the UCLA folks suggested that CKs were just metamorphosed
CVs. I wrote a column in Meteorite about that not too long ago as well. If
this is correct then a CK parent body would really likely be a CV-CK parent
body. Carl's idea then becomes a little more complicated. Either you have
to make the achondrite straight from a CV or you have to metamorphose the CV
material (perhaps by collisions, perhaps by slow heating via 26Al) to make a
CK and then melt that. It seems simpler to skip the CK step.
Alan
Alan Rubin
Institute of Geophysics and Planetary Physics
University of California
3845 Slichter Hall
603 Charles Young Dr. E
Los Angeles, CA 90095-1567
phone: 310-825-3202
e-mail: [email protected]
website: http://cosmochemists.igpp.ucla.edu/Rubin.html
----- Original Message -----
From: "Carl Agee" <[email protected]>
To: "Galactic Stone & Ironworks" <[email protected]>
Cc: "Meteorite List" <[email protected]>
Sent: Wednesday, March 12, 2014 9:06 PM
Subject: Re: [meteorite-list] Ungrouped Achondrite Prices (NWA 7325
andothers)
Hi Mike and All:
"Achondrite-ung" one of my favorite things! Also the enigmatic
groupings like ACA, LOD, WIN, BRAC, URE, fascinating! From what I have
seen and heard about NWA 7325 -- simply amazing. The problem has
nothing to do with these wonderful achondrites, the problem is our
ignorance of their possible parent bodies. Martian and lunar
meteorites are of the highest scientific value, not because they are
better meteorites, but because we know enough about their parent
bodies to make the meteorite - parent body connection and thereby they
become the equivalent of geological sample returns. If NASA hadn't
sent missions to the Moon or Mars we would most likely not recognize
these meteorites as lunar and Martian. So, the problem with Mercurian
meteorites is not whether they do or don't exist, the problem is our
fragmentary understanding of the planet Mercury and our inability, at
this time, to make the parent body - meteorite connection. Yes,
Mercury Messenger has given us new insight into the make up of the
Mercurian crust, but the data are simply still not good enough to be
useful for unequivocal meteorite matching. So even if we have a
meteorite from Mercury somewhere in the world's collections right now,
we won't know it until Mercury is better known. Part of the problem is
that Mercury possesses no true atmosphere. Remember, the strongest
evidence for martian meteorites being from Mars is trapped martian
atmospheric gases in the meteorites -- the ultimate fingerprint.
Interestingly, we may have a better shot at recognizing a meteorite
from Venus, since the Venusian atmosphere has been geochemically and
isotopically measured by NASA missions and spectroscopically from
Earth. For example, trapped Venusian atmosphere should have a
gigantically large ratio of deuterium to hydrogen. In the meantime,
there are other ways to think about parent bodies of achondrites --
identifying their meteoritic precursor material. For example, I
recently worked on achondrite-ung NWA 8186 that appears to be the
first example of an achondrite that is a very good match for having a
CK-chondrite precursor -- in other words, take a CK parent body,
igneously melt it, and the product is achondrite-ung NWA 8186. Hey,
who said the list was boring? Mike, great discussion topic!
Carl Agee
*************************************
Carl B. Agee
Director and Curator, Institute of Meteoritics
Professor, Earth and Planetary Sciences
MSC03 2050
University of New Mexico
Albuquerque NM 87131-1126
Tel: (505) 750-7172
Fax: (505) 277-3577
Email: [email protected]
http://meteorite.unm.edu/people/carl_agee/
On Wed, Mar 12, 2014 at 6:29 PM, Galactic Stone & Ironworks
<[email protected]> wrote:
Hi Listees,
Can someone elaborate on why NWA 7325 and it's possible pairings are
selling for $10,000/g in some cases? There is speculation that it
originated from Mercury, but that is only speculation at this point.
One can speculate anything. Heck, it might be from Alpha Centauri.
There are 60 other ungrouped achondrites and some of them have very
unusual characteristics. Why is NWA 7325 priced so high above the
others? The low-TKW does not explain the price (maybe in small part),
given the fact that pairings appear to be surfacing.
This is not a criticism of any dealer or dealers. I am just curious
how people have arrived at this price.
Best regards,
MikeG
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