[meteorite-list] Meteorite Question

From: Rhett Bourland <rbourlan_at_meteoritecentral.com>
Date: Thu Apr 22 10:00:06 2004
Message-ID: <IOEBKAHMGFBDJMOFGDFNEEGCDNAA.rbourlan_at_evansville.net>

Hello all again,
For those of you who have the new Encyclopedia of Meteorites by Richard
Norton and look in the appendix he has a list of the various different
classifications that was taken from a paper by Dr. Rubin at UCLA. One of
those that you don't often see is HH which is based on inclusions in the
Netschaevo iron. Whether this classification is correct or not is still up
in the air but one of the meteorites that seems to back this idea up a bit
is Burnwell. Almost all of its values are outside of what you would expect
for an H chondrite and look as if there are further extensions of the LL-L-H
values with Burnwell being the next step. I'll be the first to admit that
it could just mean that Burnwell is an extension of the H chondrites that
we've yet to sample but it could quite easily be the first meteorite of a
new class. The only problem is that Burnwell is the only known meteorite
with such extreme values and until we have more meteorites with similiar
values it will be next to impossible to say for sure. Whichever way it
falls (anomolous H chondrite or HH chondrite) I still think its probably the
coolest meteorite I've ever seen and definitely the best in my collection.
Best wishes to all,
Rhett Bourland
www.asteroidmodels.com
www.asteroidmodels.com/personal
www.meteoritecollectors.org

-----Original Message-----
From: meteorite-list-admin_at_meteoritecentral.com
[mailto:meteorite-list-admin_at_meteoritecentral.com]On Behalf Of Bernd
Pauli HD
Sent: Saturday, July 13, 2002 12:59 PM
To: rochette
Cc: Meteorite List; rbourlan_at_evansville.net
Subject: [meteorite-list] Meteorite Question


Pierre Rochette a écrit:

> the inference "this is an anomalous meteorite" should
> not be put forward before answering the questions: ...

Bonjour Pierre, hello List,

I absolutely concur and that's why I cautiously spoke of "exceptions
to the rule" instead of using a designation like "anomalous meteorite".

> excluding type 3, finds and incompletely classified meteorites and
allowing
> for a half percent error leave practically no anomalies in Bernd's list!

Right on target again! By the way, today I received an email from the
Sahara Team (Richard & Roland Pélisson), informing me about the range
of fayalite in the DaG 862 (main mass in their possession). The range
is:

Olivine Fa14.4 (0.33-32.29); pyroxene Fs13.1 (1.09-32.21)

Of course, I shouldn't have included this meteorite in
my overview as it is an unequilibrated H3 chondrite!

> By the way why is Burnwell not fully classified?

Burnwell has not yet been definitely classified or
grouped because of some exotic characteristics:

- lower Fa in olivine
- lower Fs in orthopyroxene
- lower Co in kamacite
- lower FeO in the bulk chemical analysis
- lower D17O than other equilibrated OC's
- ordinary chondrites
- higher Fe,Ni metal than other H chondrites

Thus, some meteoriticists postulated an "HH" classification but
Russell S.S. et al. (1998)are hesitant since this would imply
a genetic significance that has not yet been fully ascertained.
They use the term "low-FeO chondrite" instead to describe the
Burnwell meteorite.

Reference:

RUSSELL S.S., McCOY T.J., JAROSEWICH E. and ASH R.D. (1998)
The Burnwell, Kentucky, low iron oxide chondrite fall: Description,
classification and origin (Meteoritics 33-4, 1998, 853-856).


Best regards,

Bernd

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Received on Sat 13 Jul 2002 06:46:22 PM PDT