[meteorite-list] Pairing discussion/questions

From: Jeff Grossman <jgrossman_at_meteoritecentral.com>
Date: Mon, 18 Jan 2010 13:12:53 -0500
Message-ID: <4B54A4A5.7040200_at_usgs.gov>

Zelimir brings up one more case that I didn't cover... when two names
are given to the same physical stone. If the NomCom learns of this and
can be sure that this is what happened, they can abolish one of the names.

jeff

On 2010-01-18 12:46 PM, Zelimir Gabelica wrote:
> Hi Greg,
>
> This might be a typical question for Jeff Grossman.
>
> I am also continuously puzzled by the abundance of paired meteorites
> (thus those that are officially recognized as such).
>
> Let's suppose that once one (or a few) meteorite(s) are selected from
> an important lot (as found) and sold to someone, this someone
> (scientist, collector....) would envisage its classification.
> And the same will possibly happen with the other meteorites from the
> same lot.
> As a result, there will be as many different NWA numbers, as
> independent classifications (of the - probably- same meteorite).
> As most of these classifications probably won't be concerted, there
> will not be pairings reported and we will end up with as many
> different meteorites, most probably of the same type, that will never
> be suspected being paired.
>
> If a pairing is suspected, I believe this results from "concerted"
> analyses (of either meteorites stemming from the same lot and analyzed
> by different groups, or of the same meteorites provided by different
> finders (buyers....) brought for analysis to the same group).
>
> This even complicates further if there are more than one such "lot"
> found (meteorite shower spread throughout a large strewnfield).
>
> In case of such "concerted" analyzes, I guess that the labs will still
> give a different NWA number to each meteorite (or group of meteorites
> from the same lot) analyzed, because one is never sure that 2
> meteorites supposed to come from the same lot are at 100% the same.
> If pairing is reported, then most of the time (not always) it is
> mentioned in the Met. Bulls.
> But because all analyzes were done independently, each analyzed
> meteorite (or group of meteorites from the same verified lot) will
> receive its own NWA number.
>
> Here I realize that, at that stage, it is very difficult to decide to
> only retain as official the first NWA number attributed
> chronologically and to cancel all the next NWA numbers.
>
> I for one am just happy when pairings are reported. This is often the
> case for "important" types such as the planetaries.
> But for the "common" H6's or L5's, I believe this is very seldom done.
>
> So far, regarding my collection catalogue, here is what I mention (for
> my NWA 4857 sample taken as an example), just to have an idea of the
> total mass of that meteorite evaluated so far.
>
> NWA 4857 (Algeria, Shergottite enr maf), 0.928 g in collection;
> tkw:1 at 24 g:
>
> ....Paired with NWA 2975 (70.1 g), NWA 2986 (170 g), NWA 2987 (82 g),
> NWA 4766 (225 g), NWA 4783 (120 g), NWA 4864 (94 g), NWA 4878 (130 g),
> NWA 4880 (81.6 g), NWA 4930 (117.5 g), NWA 5140 (7.5 g), NWA 5214
> (50.7 g), NWA 5219 (60 g), NWA5313 (5.3 g) and NWA 5366 (39.6 g).
> Cumulated tkw: 1273.3 g (as per Jan. 2010)
>
> I know that this neither sheds more light to the problem, nor answers
> your concerns.
> Hopefully someone can add more to the issue.
>
> My best,
>
> Zelimir
>
>
> At 17:09 18/01/2010, Greg Catterton wrote:
>> I have often wondered and after some discussion with others I wanted
>> to get the community feeling on the issue of pairings.
>>
>> If a meteorite say NWA 1877 for example is out there and more is
>> recovered and verified to be the same material from the same
>> strewnfield, should the new material share the NWA number and the TKW
>> be updated?
>> I have noticed many pairings with NWA 1877 and many other meteorites.
>> Same material with different numbers and TKWs listed.
>>
>> Would it not be in the best interest to have all the paired samples
>> share on number? This would surely cut the amount of NWA material by
>> 1000 or more.
>> Why is this not done?
>>
>> What is the process for pairing material to share the NWA number?
>> Is it up to the dealer or the person who did testing?
>>
>> What affect would it have on value if something with a listed TKW of
>> 200g suddenly was paired with the 3 other numbers assigned to the
>> same material and the TKW was pushed to 1kg or more?
>> Surely it would decrease as supply grew. Is this a concern for some?
>>
>> I am trying to better understand the politics/red tape that goes with
>> this area.
>>
>> Thanks, hope everyone is doing well.
>>
>> Greg C.
>>
>>
>>
>>
>>
>>
>>
>>
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>
> Prof. Zelimir Gabelica
> Universit? de Haute Alsace
> ENSCMu, Lab. GSEC,
> 3, Rue A. Werner,
> F-68093 Mulhouse Cedex, France
> Tel: +33 (0)3 89 33 68 94
> Fax: +33 (0)3 89 33 68 15
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-- 
Dr. Jeffrey N. Grossman       phone: (703) 648-6184
US Geological Survey          fax:   (703) 648-6383
954 National Center
Reston, VA 20192, USA

Received on Mon 18 Jan 2010 01:12:53 PM PST