[meteorite-list] Capot Rey...photos please of the H5

From: Martin Altmann <Altmann_at_meteoritecentral.com>
Date: Fri Sep 23 06:08:31 2005
Message-ID: <001401c5c028$46b1a800$6f559a54_at_9y6y40j>

Hi Jeff,

as far as I understand the term "IMB" does not name a completely and
uniformly molten rock.
Else, I would have have problems to understand the "B", if there aren't any
fragments of the precessor material to be found in the melt (and I think, we
easily will sled into the PAC corner).
Different classification of the same find as IMB or H5 f.i. are easily
explainable. Take for instance Dho 010, there you have broad streams of melt
flowing around chondritic fragments in different stages of melting, some
even unaltered, therefore one can determinate the type (have to look Dho 010
if I remember right is H6).
And furthermore take our good old Gao! There you have stones, which are
simply more or less normal chondrites, other stones show large melt pockets
and again others are more or less totally molten and have to be regarded, if
one doesn't know about the other average Gao specimens, with no doubt as
IMBs. Take a look on David Weir's page, there you have such an example.
Thus with Gao we have the whole spectra - H5, H5 with melt, IMB.
It's always the same, it depends what for a stone the classificators get,
what for sections they do have.
Remember the NWA 1109, they caught parts with slightly below 10% Dio, thus
it's an EUC-P, another cut, another stone from the same find with >10%,
voila they had to call it a How.
Take also good old Zag. There exist pieces with only a single lithology, if
those would have been handed in for typing, Zag wouldn't have bin classified
as regolith breccia. Take the NWA-Rumurutis, some are nice brecciae,
result - obviously paired ones (lalalaa I know, I'm not a scientist, but if
it's looking the same in every detail and the stuff is so rare) got
different classifications. Some R4s are paired with R3-6...
Ooops, all I'm writing here, is about the optical, physical appearance of
the stones, not chemically.

Now, I would guess, with Capot Rey, they took either a piece without melt
(if exists) or determinated the type from a not molten fragment in the melt.

But look at the phantastic pieces of Carsten, those dark fat rivers of melt
around the grey round jigsaw pieces. Hence if Dho 010, who looks the same,
but is only much more weathered, was called a IMB, I dare to say in my
Lieschen-Mueller-opinion
(Lieschen Mueller is the German sister of John Doe), Capot Rey is an IMB
too.

Of course again we would need a concretion of terms from a qualified mouth.
With type-7 vs. PAC vs. IMB we learned, that it has to do with the isotopes
and in general nobody is sure about the criteria,
now we have IMB vs. MR (melt rock) vs H or L with IMB vs H or L with visible
huge parts of melt, but not assigned,
or we have to resign ourself to being more types of rock out there in space
as we have terms for them :-)

Buckleboo!
Martin


----- Original Message -----
From: "Jeff Kuyken" <info_at_meteorites.com.au>
To: "drtanuki" <drtanuki_at_yahoo.com>; <meteorite-list@meteoritecentral.com>
Sent: Friday, September 23, 2005 10:57 AM
Subject: Re: [meteorite-list] Capot Rey...photos please of the H5


> I would be a bit cautious about calling something an IMB unless it has
been
> formally classified as such. My understanding is that this meteorite was
> classified as H5 but after further cutting later was found to be highly
> shocked. Let's not forget that IMB is basically a scientific term
referring
> to the fact that the pressure reached about 75-90 GPa and is rated as S6+.
> It's original shock rating was only S2. A new piece should probably be
> submitted for re-classification so a proper determination can be made.
>
> Cheers,
>
> Jeff
>
> ----- Original Message -----
> From: drtanuki
> To: meteorite-list_at_meteoritecentral.com
> Sent: Friday, September 23, 2005 9:47 AM
> Subject: [meteorite-list] Capot Rey...photos please of the H5
>
>
> Dear List,
> Does anyone have more information about Capot Rey?
> It is listed as an H5 in the MetBul and has no mention
> of it being an IMB. I would appreciate photos if
> someone has them of their samples that were not sold
> as an IMB. Thank you in advance.
> Sincerely, Dirk Ross...Tokyo
>
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Received on Fri 23 Sep 2005 06:18:28 AM PDT