[meteorite-list] RICHLAND

From: Jeff Grossman <jgrossman_at_meteoritecentral.com>
Date: Tue, 20 Mar 2007 08:20:03 -0500
Message-ID: <OFB835B1B5.2158F961-ON852572A4.0043C0B1_at_usgs.gov>

First of all, for the many of you without access to Geochimica et
Cosmochimica Acta, here is the quote from Wasson, J.T., Huber, H.,
and Malvin, D.J. (2007) Formation of IIAB iron meteorites. GCA 71, 760-781:

>The 47-kg Fredericksburg (Texas) iron was first reported
>to us by a person living in Alaska, who stated that it had
>been inherited from a deceased relative who had lived near
>Fredericksburg. Our analysis of the sample shows that,
>within error, its composition is the same as that of the
>Richland (Texas) iron. Both irons appear to be strongly
>weathered. However, these two Texas locations are
>297 km apart, farther apart than plausible for a strewn
>field. Our best guess is that human transport has been involved,
>and that they are fragments from the same fall
>event. Fredericksburg is not an approved name; we suggest
>that this mass be referred to as Richland (Fredericksburg)
>unless future studies imply that it resulted from a distinct
>fall.

There are many irons with multiple named masses, although all of the
masses share the same formal name, in this case "Richland." For
historical reasons, as well as to recognize to possibility that
pairings are never 100% certain, the names of the individual masses
are frequently preserved in catalogs and the literature, and should
be preserved by dealers and collectors as well. In this case,
changing the "main mass" designation (which I consider to be a sloppy
term) doesn't really help the situation. It will always be better to
refer the new piece as the "Fredericksburg mass of Richland" or, as
Wasson suggests, the "Richland (Fredericksburg) mass".

Another classic example of an iron with multiple named masses is
North Chile, which includes, among others, the well-known Filomena
and Tocopilla masses.

I've now added the Richland synonyms to the MetBull database.

Jeff

At 01:21 AM 3/20/2007, Sterling K. Webb wrote:
>Hi, All,
>
> Strictly as a dumb and innocent bystander on the
>Thread: Illinois Irons, which is now and forever more
>shall be about a Texas/Alaska Iron, I have a dumb
>and innocent question (lamb to the slaughter).
>
> Here's what the Catalogue of Meteorites says
>about RICHLAND:
>
>A mass of 30lb (13.6kg) was found when
>an old well was being cleaned out. Listed,
>F.C. Leonard (1956).
>
>Analysis, 5.56 %Ni, E.P. Henderson &
>O.E. Monnig (1957).
>
>It has been suggested that it is a transported
>piece of Coahuila, but is chemically distinct.
>More recent analysis, 5.40 %Ni, 60.6 ppm.Ga,
>182 ppm.Ge, 8.2 ppm.Ir, J.T. Wasson (1974).
>
>Structurally distinct from Coahuila; shock-melted
>troilite, V.F. Buchwald (1975).
>
> Here's my dumb and innocent question: If the
>mass of RICHLAND is 13.6 kilos and the mass of
>(RICHLAND (FREDERICKSBERG) is 47+ kilos,
>and FREDERICKSBERG is a piece of RICHLAND,
>isn't Mike's 47 kilos (you carried it thru the airport?)
>the Main Mass?
>
> Naive little physicist says if they are two pieces
>of the same meteoroid that fell at the same time, the
>biggest piece is the Main Mass, as in, that corresponds
>to the physical reality.
>
> OK, ready for the beaurocratic axe to fall.
>
>
>Sterling K. Webb
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Dr. Jeffrey N. Grossman phone: (703) 648-6184
US Geological Survey fax: (703) 648-6383
954 National Center
Reston, VA 20192, USA
Received on Tue 20 Mar 2007 09:20:03 AM PDT