[meteorite-list] Meteorite Question

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

Hello Bernd and list,
Glad to see that my question has drawn some discussion and especially happy
to see Bernd answered.
I'm not suprised to see wide ranges of fayalite within type 3 chondrites as
those have not been homogenized and it would actually be expected that some
rather extreme values listed. The one meteorite you mentioned that got my
attention were the ones that are a type 4 or above. I'm wondering if you
have any other information on the pyroxene and metal values of some of
these.
Thanks,
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: Friday, July 12, 2002 2:10 PM
To: rbourlan_at_evansville.net
Cc: bernd.pauli_at_lehrer1.rz.uni-karlsruhe.de; Meteorite List
Subject: [meteorite-list] Meteorite Question


Rhett Bourland wrote:

> On the lower end of the H chondrite values there is a very
> small bar on 15%. I was wondering if you could possibly tell
> me how many meteorites are represented by that bar and if
> there aren't too many which ones are they?


Hello Rhett and Fayalists :-)

In the lower left corner of that graph you find my name and the
date when this graph was generated: October 23, 1994 so I think
that the 4th edition of the Meteorite Catalogue, the Big Blue
Book, was the basis for this graph.

Presently there are six H chondrites with fayalite values ranging
from 15 to 16 % fayalite. These include the following:

Name Class Fell/Find Year Fa

Xinyi H5 Find 1975 15
Willaroy H3 Find 1970 15
Grady (1937)H3.6 Find 1937 15
Burnwell H Fell 1990 15,8
DaG 385 H3-4 Find 1997 15,9
Clipperton H3 Find 1986 15,9

The 1994 graph shows Xinyi, Willaroy, and Grady (1937).

> Dr. McCoy at the Smithsonian was talking about that meteorite
> having a Fa content of 15.8 +/- .2% and stated that the average
> Fa composition of H chondrites is only between 16.9-20.4%.
> Obviously there will be some meteorites within that class that
> are slightly above or below average so I was wondering about the
> ones that are a bit lower than that and any possible relationships
> they may have to Burnwell.

Well, meanwhile there are actually H chondrites
with even lower Fa values in my databases:

Name Class Fell/Find Year Fa

C.los Calvos H4 Find 1986 12,5
Suwahib H3.7 Find 1931 14,4
DaG 862 H3 Find 1999 14,4

As for the US Antarctic H chondrites, I have the following:

NAME DESIG FA

FRO 95038 H4 14.7
FRO 95014 H4 14.8
ALH 77221 H4 15
EET 87553 H4 15
EET 87808 H4 15
ALH 84105 H6 15
EET 96037 H4 15
EET 96047 H4 15
GRV 99025 H5 15.6

This overview does not include ones with variable Fa values or
ranges, especially the unequilibrated specimens. Some examples
so that you know what I am talking about:

NAME DESIG FA

GRA 98087 H3.8 01-19
LEW 88500 H3.7 01-20
WSG 95300 H3.3 01-21
LEW 88315 H3.5 01-22

> the average Fa composition of H chondrites
> is only between 16.9-20.4% ...

As for the upper value of 20.4% fayalite, there
are also some "exceptions to the rule":

Name Class Fa

DaG 536 H6 21
Cleo Springs H4 21
Oakley (stone) H6 21
Forrest 031 H4 21
Menindee L. 002 H5 21,1
Glenrothes H5 21,4
Acfer 316 H6 21,4
Dhofar 063 H5 21,4
Oviedo H5 25

US Antarctica:

FRO 90081 H6 21.4
FRO 90131 H4 21.2


Best wishes,

Bernd

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Received on Sat 13 Jul 2002 06:29:24 PM PDT