[meteorite-list] Term Main Mass

[Michael Farmer]

Dr Grossman,
Thanks, this is exactly what I have been saying. If you are going to give it 
a different name, then you must be able to use the term main mass with the 
pairing. I personally don't like the pairings being named (take for example 
NWA 801. I go to Morocco often, and I go right to the strewnfield outside 
Zagora every time I go. I immediately get besieged by children and people 
who all recognize me and run up selling me whatever piece of this CR2 
meteorite they have found over the previous few months in my absence. I sell 
them all as NWA 801, since it is the same meteorite, I do not submit them 
all for naming, I would have over 500 new CR2 meteorites if I did).
When I get a meteorite, like NWA 2046 Martian for example, it gets cut up 
and the largest piece is the main mass, some lucky owner has the bragging 
rights to claim that they own the largest remaining piece. No pairings have 
ver been found of it, so no issue there.
Mike Farmer
----- Original Message ----- 
From: "Jeff Grossman" <jgrossman at usgs.gov>
To: <meteorite-list at meteoritecentral.com>
Sent: Friday, January 20, 2006 5:38 AM
Subject: Re: [meteorite-list] Term Main Mass


>I basically endorse the below statement by John.  As for how the NomCom 
>uses the term "main mass," it is applied to the entity being described in 
>the writeup.  These writeups in the Bulletin are very specific about what 
>material is to get each name.  "Main mass" refers back to that. If somebody 
>wanted to put a statement in the Bulletin like "NWA 7554 is the main mass 
>of the NWA 6788 pairing group," I would also find that to be an appropriate 
>usage, and could vote to accept it for the Bulletin.
>
> I do differ with John on one minor point:  we don't use the term only for 
> the largest piece in a group of meteorites assigned to a particular 
> number.  We would also use it to describe the remaining largest mass of a 
> single stone that has been cut or broken up for distribution.
>
> I also must take umbrage at the statement made in Doug's post referring to 
> the "not especially peer reviewed appendix of MAPS."  All articles in the 
> supplement issue get full peer review.  Only the MetSoc abstracts do not. 
> The MetBull is highly peer-reviewed.  The Editor and Assoc. Editors 
> produce writeups, and a committee of 13 scientists review each one.  Many 
> writeups also go out for review by scientists outside the NomCom.  I 
> realize that this is not a traditional peer review conducted by a 
> independent editor, but it is a very, very high degree of peer scrutiny.
>
> jeff
>
> At 12:46 AM 1/20/2006, Arizona Skies Meteorites wrote:
>>As most of us are aware, NWA numbered meteorites are
>>not in any way analogous to meteorites coming out of a
>>well characterized strewn field-that's precisely why
>>they are given NWA numbers. Those that understand the
>>NWA numbering system also understand that the main
>>mass of one NWA numbered group may or may not be the
>>'biggest piece' of the presumed "fall". In fact, the
>>use of the term 'main mass' in respect to NWA
>>meteorites has nothing to do with the 'fall' per se,
>>but rather is the term used to refer to the largest
>>piece in a group of meteorites assigned a particular
>>NWA number. Even the "pairing" of meteorites does not,
>>and can not guarantee that they are part of the same
>>fall. This is especially true in the case of northwest
>>Africa where meteorites are collected over a vast area
>>with little or no record of their coordinates. Since
>>it will never be known whether "paired" NWAs are
>>actually part of the same fall or not, it seems that
>>the term main mass is appropriate unless one can
>>unambiguously state with complete certainty that two
>>NWA numbers are from the same fall. This can not be
>>done without a precise record of coordinates. In our
>>opinion this discussion over the use of "main mass" is
>>just a matter semantics, and has nothing to do with
>>science what-so-ever. That said we can probably bring
>>this thread to an end.
>>
>>
>>Cheers
>>
>>
>>-John
>>
>>
>
> Dr. Jeffrey N. Grossman       phone: (703) 648-6184
> US Geological Survey          fax:   (703) 648-6383
> 954 National Center
> Reston, VA 20192, USA
>
>
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