[meteorite-list] nwa869

From: Matteo Chinellato <mcomemeteorite2000_at_meteoritecentral.com>
Date: Thu Apr 22 10:00:05 2004
Message-ID: <20020707073705.5189.qmail_at_web10303.mail.yahoo.com>

Hello all

The problem for me in this meteorite is the inclusions
find into, many have strange inclusions type diogenite
- I have a slice where is visible a many similar
Bilanga piece type material - others have big white
inclusions, others black rounded or spot inclusions
and etc... who analyzed this meteorite probably find
problems for the classification for this inclusions,
and the type change - L6, L3/4.4, etc... - this
meteorite is many strange and probably is good study
very well this, in the NWA 900 slice visible in the
Norton Book, the inclusions is many similar to the
Zagami matrix and have a probably melt, for the moment
the meteorite is under study in Germany and I waith
the analysis for see what is it.
Regards

matteo

--- John Divelbiss <j.divelbiss_at_worldnet.att.net>
wrote:
> Al,
>
> Your point is well taken on the source aspect of
> this discussion. As with
> any type, no matter the name or number assigned to
> it...there is good chance
> they are from the same asteroid. HED's from Vesta,
> etc.
>
> I just looked at the group I have and quite frankly
> it is not easy to say
> they are different materials. Even under the scope.
> Yet I see the reports of
> L4 or L5 for NWA 869, L6 for 787, now L3.4/4 for
> 900, and similar
> suspicions for 995 (not 905 that I listed in earlier
> message). Thin sections
> of each one may help...but as Dean has stated, his
> section may have thrown
> off the evaluation of his sample relative to its
> true petrologic type.
>
> All this makes me wonder about the process and
> "accuracy" of identifying a
> particular fall or find. As I understand it, the
> boundaries between H's and
> L's can be somewhat blurred when metal and iron
> contents are in the
> transition percentage levels. All the more
> bewildering. I'm glad I'm not
> assigning these things. How does one know when he or
> she has got it right?
> Personally I'm going like them all for being rocks
> from space. With that in
> mind is seems silly to argue between one fall or #
> versus another with "mine
> is different than yours"... when at first look they
> do not appear to be any
> different.
>
> I will however be cautious of paying too much for so
> called petrological
> type of 3's and 4's when it isn't obvious. I'll
> stick with "do I like it or
> want it or not, relative to the price it is offered
> at ?".
>
> Thanx again Al for response,
>
> John Divelbiss
>
>
> ----- Original Message -----
> From: "almitt" <almitt_at_kconline.com>
> To: "John Divelbiss" <j.divelbiss_at_worldnet.att.net>
> Cc: "Matteo Chinellato"
> <mcomemeteorite2000_at_yahoo.it>; "dean bessey"
> <deanbessey_at_hotmail.com>;
> <meteorite-list_at_meteoritecentral.com>
> Sent: Saturday, July 06, 2002 6:07 PM
> Subject: Re: [meteorite-list] nwa869
>
>
> > Hi John and all,
> >
> > Many of the parent bodies have yet to be identify
> to the many of the
> meteorites we
> > have accumulated here on Earth. However there are
> some suspect parent
> bodies which
> > have been identified by spectral matches to the
> asteroids and meteorites.
> One such
> > match is asteroid Hebe for the H type chondrites.
> It is obvious from
> looking at Hebe's
> > surface that it has a variation in spectra as the
> asteroid rotates
> representing the
> > different metamorphism (classes) we see from the
> change in olivine to
> pyroxene ratio.
> > No doubt the asteroid had a large enough impact at
> one time to knock it
> apart allowing
> > the more differentiated classes to show up on the
> outside, and some of the
> outer part
> > of the asteroid became buried in the interior as
> it reassembled into a
> rubble pile
> > asteroid. It isn't uncommon for H type chondrites
> to have brecciation of
> various
> > different classes all in one meteorite. A good
> example of this is Zag
> (H3-6) and
> > Noblesville, Indiana an H4 chondrite with H6
> clasts. Probably why we get
> so many of
> > the H type chondrite material now is we are living
> at a time when the
> results of the
> > impacts which have been migrating to us over the
> eons have finally made
> their way to
> > fall at a constant rate. If we lived in a
> different time many years from
> now or very
> > long ago then perhaps and most likely we would
> sample some other type of
> meteorite
> > falls. Perhaps it wouldn't be uncommon for some
> rare type meteorite (to
> us) to fall at
> > a regular more consistent rate.
> >
> > How does this tie into NWA 869. As stated earlier
> we don't know all of the
> parent
> > bodies yet (a good reason for funding to NASA to
> build a craft to visit as
> many
> > asteroids as we can) However there is one asteroid
> of about 7 km in
> diameter that
> > resides in the main belt and may be related to the
> L type chondrites and a
> possible
> > parent body though a very weak link. Asteroid 3628
> Boznemcova exhibits
> spectral
> > qualities to the L's and LL's. It is obviously too
> small to be a complete
> asteroid and
> > has been suggested it is a fragment of a much
> larger asteroid. Perhaps
> this might be
> > what is left of the NWA 869 and other L type
> meteorites and why we sample
> a steady
> > rate of L type chondrites.
> >
> > Beside these parent bodies, we are fairly sure of
> the Vesta and HED type
> meteorite
> > connections as well as the Martian (SNC), and
> lunar meteorite to Moon
> connections.
> > It's what makes reading about and research on
> meteorites so exciting and
> trying to
> > figure out all of the complicated puzzles they
> present to us.
> >
> > --AL Mitterling
> >
> >
>


=====
M come Meteorite - Matteo Chinellato
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Received on Sun 07 Jul 2002 03:37:05 AM PDT