[meteorite-list] Ungrouped Achondrite Prices (NWA 7325 andothers)

From: Michael Mulgrew <mikestang_at_meteoritecentral.com>
Date: Wed, 12 Mar 2014 22:25:08 -0700
Message-ID: <CAMseTy3q-XusVm30WMGSR_yqR2XSXJnxAQO1csscJh05oUvhHg_at_mail.gmail.com>

Usually I have to buy a book to get this kind of information, great discussion!

Michael in so. Cal.

On Wed, Mar 12, 2014 at 10:00 PM, Alan Rubin <aerubin at ucla.edu> wrote:
> Almost all CKs are type 4-6; all CVs are type 3. The few CK3s seem to be
> CK3/4 or CK3.8 or so. In fact, the only way to recognize a meteorite as CK
> at all is if it is sufficiently metamorphosed to have many of the olivines
> equilibrated. If not, the rock will be classified as a CV. Since many of
> the CK4s and the few CK3s I looked crushed and fragmental, and that many CKs
> are shocked (which I showed back in 92), then it seems to me that impacts
> are the means of transforming a CV3 to a CK. Because CKs are oxidized, they
> clearly are not being made from reduced CVs like Vigarano, Efremovka and
> Leoville. Because many of the Bali oxidized subgroup have strong
> petrofabrics and CKs don't then the CKs are either being made from the
> Allende oxidized subgroup or from a third, heretofore unsampled, oxidized CV
> subgroup. Anyway, we recommended dropping the CK designation altogether
> (i.e., call rocks CV3, CV4, CV5, CV6), although the CK designation is so
> entrenched by this point, that I doubt that this will happen.
> So, with this background, you could call it a CV-CK parent body, or simply
> just a CV parent body. One final point, how many CV or CV-CK parent bodies
> are there? We don't know tha answer to that question for any chondrite
> group. There may be only one of some groups represented in our collections,
> or there may be several. (Nearly half of the H chondrites have the same CRE
> age of about 7.6 Ma), so these samples were all on the same parent body at
> that time. Other samples may have been on other H chondrite parent bodies
> or at distant locations on the same parent body. We don't know. But since
> asteroids tend to b reak into smaller bodies via a collisional cascade, it
> may well be that by the time the collision occurred that gave us half of the
> H chondrites, the original parent H chondrfite asteroid had already been
> broken into several chunks, only one of which was struck at that time. The
> same may be true for many kinds of meteorites.)
> 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: aerubin at ucla.edu
> website: http://cosmochemists.igpp.ucla.edu/Rubin.html
>
>
> ----- Original Message ----- From: "Carl Agee" <agee at unm.edu>
> To: "Alan Rubin" <aerubin at ucla.edu>
> Cc: "Galactic Stone & Ironworks" <meteoritemike at gmail.com>; "Meteorite List"
> <meteorite-list at meteoritecentral.com>
> Sent: Wednesday, March 12, 2014 9:35 PM
> Subject: Re: [meteorite-list] Ungrouped Achondrite Prices (NWA 7325
> andothers)
>
>
>> Alan,
>>
>> Thanks, you just saved me from a savaging by reviewers of my paper
>> still "in prep"! I guess CK 'precursor' is a safer term than 'parent
>> body'? Or are we calling it the CV-CK parent body? (with the UCLA good
>> housekeeping seal of approval). I'm happy with just melting a CV, I
>> used to do that all the time in the lab, except at very high pressure.
>>
>> Carl
>> *************************************
>> 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: agee at unm.edu
>> http://meteorite.unm.edu/people/carl_agee/
>>
>>
>>
>> On Wed, Mar 12, 2014 at 10:26 PM, Alan Rubin <aerubin at ucla.edu> wrote:
>>>
>>> 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: aerubin at ucla.edu
>>> website: http://cosmochemists.igpp.ucla.edu/Rubin.html
>>>
>>>
>>> ----- Original Message ----- From: "Carl Agee" <agee at unm.edu>
>>> To: "Galactic Stone & Ironworks" <meteoritemike at gmail.com>
>>> Cc: "Meteorite List" <meteorite-list at meteoritecentral.com>
>>> 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: agee at unm.edu
>>>> http://meteorite.unm.edu/people/carl_agee/
>>>>
>>>>
>>>>
>>>> On Wed, Mar 12, 2014 at 6:29 PM, Galactic Stone & Ironworks
>>>> <meteoritemike at gmail.com> 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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>>>>> -------------------------------------------------------------
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>>>>>
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>>>>
>>>>
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>>>
>
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Received on Thu 13 Mar 2014 01:25:08 AM PDT