[meteorite-list] Park Forest Main Mass Status

From: Jeff Grossman <jgrossman_at_meteoritecentral.com>
Date: Thu Apr 22 10:25:34 2004
Message-ID: <5.1.0.14.2.20030502110609.00b03c68_at_gsvaresm02.er.usgs.gov>

Hi all,

Well, we don't really have a definition, so I only have my own
opinion. The "main mass" of a meteorite is a term used to identify a
single dominant piece of a meteorite, or, sometimes, the largest remaining
piece of what was once a main mass. By "piece" I mean recovered piece, not
pre-impact piece. I would think that Park Forest has no main mass (although
I haven't seen a list of recovered masses), nor does Holbrook or many other
showers of small stones. Peekskill has a main mass. Norton County was a
shower, but it has a main mass by anyone's definition, since one piece
weighed a ton, 10x more than any other. Canyon Diablo probably doesn't
have a main mass.

If I had to write a guideline for the use of this term, my first draft
would say that it is the largest piece of a fall, and must either comprise
at least 50% of the total recovered mass or be 2x the mass of any other
piece. I'm sure I'd get arguments.

I suppose you're all going to look in the MetBull and find cases where we
didn't follow this definition. We haven't really been worrying about it.

jeff

At 10:41 AM 5/2/2003, David Weir wrote:
>Hello Mark,
>
>Take a look at any MetBul entry and it appears to me that they use the
>term "main mass" to mean that portion of a stone or stones that remains
>the largest piece (or maybe pieces?) of the total. I suppose it could
>also be used to describe the largest mass that is recovered but it then
>should be so stated to avoid confusion with the MetBul terminology. This
>is definitely a subject that should be clarified by Dr. Grossman.
>
>David
>
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Dr. Jeffrey N. Grossman
Chair, Meteorite Nomenclature Committee (Meteoritical Society)
US Geological Survey
954 National Center
Reston, VA 20192, USA
Phone: (703) 648-6184 fax: (703) 648-6383
Received on Fri 02 May 2003 11:30:58 AM PDT