[meteorite-list] CONCEPTION JUNCTION, MISSOURI PALLASITE - AD/test

From: Dave Gheesling <dave_at_meteoritecentral.com>
Date: Sat, 27 Aug 2011 19:50:52 -0400
Message-ID: <B22BC71D6B754FB58E92A1D4BACB4ECA_at_meteorroom>

Michael & All,

Dr. Wasson submitted his classification of the Conception Junction pallasite
(PMG) to the Nomenclature Committee last month, and presumably it will be
posted to the Meteorite Bulletin before long. Since much of this
information is not publicly available at the moment, please find below an
excerpt from Dr. Wasson's contribution to the monograph. He also complied
an interesting chart for comparative analysis, but I'm not sure how to post
that information with plain text. Anyway, hope this helps answer some of
the good questions that have been posted:

"The information I report here shows there is no main-group pallasite that
is closely related to Conception Junction. Conception Junction is unique.

"If I compare Conception Junction with other main group pallasites (PMG)
with Au contents within 10% of that in Conception Junction (i.e. in the
range 2.0 to 2.5 mg/g Au), only Seymchan and PCA 91004 have Ir
concentrations within a factor of two of that in Conception Junction.

"If I sort on Ir, I find that there is no other PMG among the 40 that I have
studied that has a closely similar Ir value. The nearest are Pescora
Escarpment 91004 (0.76 mg/g Ir), Seymchan (0.67 mg/g) and Barcis, a scarcely
studied Russian PMG (0.32 mg/g Ir).

"The Co content of this sample is high (6.0 mg/g). If I sort my PMG data on
the basis of Co, I find that there are three irons with higher Co, namely
Krasnojarsk, Rawlinna 001 and one sample of Phillips County, and a couple
more that are slightly lower, namely Springwater and Zaisho.

"The Ni content is also rather low, as is shown in the chart below comparing
Conception Junction to PCA 91004, Seymchan, Barcis and Krasnojarsk.

"In summary, the composition of the metal in Conception Junction differs
from all other known pallasites."

All the best,

Dave
www.fallingrocks.com
www.conceptionjunctionpallasite.com
 

-----Original Message-----
From: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of Michael
Fowler
Sent: Saturday, August 27, 2011 4:04 PM
To: meteorite-list at meteoritecentral.com
Cc: Michael Fowler
Subject: [meteorite-list] CONCEPTION JUNCTION, MISSOURI PALLASITE - AD/test



Wasson's statement that:

.there is no main-group pallasite that is closely related to Conception
Junction. Conception Junction is unique."

leaves open the question at to what is the classification? Is it ungrouped,
or perhaps, main group anomalous?

I would be most interested to know the major and trace element analysis so I
could form my own opinion.


Sincerely,

Mike Fowler
Chicago

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Received on Sat 27 Aug 2011 07:50:52 PM PDT