[meteorite-list] metachondrite

From: Jeff Grossman <jgrossman_at_meteoritecentral.com>
Date: Thu, 21 Oct 2010 13:39:07 -0400
Message-ID: <4CC07ABB.5010508_at_usgs.gov>

  Even if the term "metachondrite" comes into use, it will not be the
name of a meteorite group. It is semantically similar to the terms
chondrite and achondrite, which are descriptive of the overall texture
of a rock. Each of these terms encompasses objects from many parent
bodies. And please don't think that the term "primitive achondrite" is
incoherent. It is a very well-defined term, with an abundant scientific
literature behind it. In fact, Irving et al. (metsoc abstract) suggest
that metachondrite is essentially a synonym for PAC! Nor is the term
"ungrouped" incoherent. This is a very precise term, meaning that the
meteorite does not belong to an accepted group. If one adopts the term
metachondrite, expect there to be metachondrite-ung classifications
appearing.

Jeff

On 10/21/2010 9:57 AM, Martin Altmann wrote:
> Hi,
>
>> Time will tell if it catches on.
> I suppose it will,
> because to list these stones as Achondrite-ungr or Achondrite-prim. is very
> unspecific
> (and as far as I can rate it as a sheer layman, also sometimes somewhat
> misleading),
> while the metachondrite concept is very coherent.
>
> Of course it can take some time.
> (If you remember e.g. that the Bulletin still has with the lunaites only the
> very coarse discrimination in LUN-A and LUN-B, as we would still be in the
> time, where there were only the 2 DaGs and NWA 032.)
>
> Btw. these new results and that interesting topic about the additional
> 7ers/chondritic PACs/Metachondrites came on the table or was incited, as
> far as I can see, only and solely by means of newly found stones from the
> hot deserts.
>
> Hence another perfect example, why all, also in the MetSoc, should take care
> for keeping the deserts open.
> It helps a lot!
>
> Best!
> Martin
>
>
>
>
> -----Urspr?ngliche Nachricht-----
> Von: meteorite-list-bounces at meteoritecentral.com
> [mailto:meteorite-list-bounces at meteoritecentral.com] Im Auftrag von Jeff
> Grossman
> Gesendet: Donnerstag, 21. Oktober 2010 15:02
> An: meteorite-list at meteoritecentral.com
> Betreff: Re: [meteorite-list] metachondrite
>
> This is a term coined by Ted Bunch and Tony Irving, but to my
> knowledge there is no peer-reviewed publication defining the term.
> You'll find the definition in an AGU and a MetSoc abstract:
>
> http://www.lpi.usra.edu/meetings/metsoc2005/pdf/5218.pdf
> http://adsabs.harvard.edu/abs/2006AGUFM.P51E1246B
>
> The term is not in widespread use and has not been used in the
> Meteoritical Bulletin. Time will tell if it catches on.
>
> Jeff
>
>
>
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Received on Thu 21 Oct 2010 01:39:07 PM PDT