[meteorite-list] Slashes and hyphens (and round brackets)

From: Jeff Grossman <jgrossman_at_meteoritecentral.com>
Date: Tue Jan 17 14:01:54 2006
Message-ID: <7.0.0.16.2.20060117133434.025c9ba0_at_usgs.gov>

No, it's not possible. But you will find these
in the literature, as you point out. There are
several reasons why you find these:

1) It's an error. Scientists get just as
confused by these symbols as anybody else. Shisr
010 clearly slipped through the cracks and should
have been caught editorially. Chances are, this one should have had a hyphen.

2) It's an alternative usage. There are papers
out there, e.g. Sears et al (1991) [Proc. Lunar
Planet. Sci. 21, 493-512] that use slashes in the
opposite sense as the Meteoritical
Bulletin. They classified Ngawi as LL3.2/3.7,
but if this appeared in the Bulletin today it would be LL3.2-3.7.

3) The slash was meant by the classifier to show
uncertainty rather than transition. I don't know
of any specific examples, but it's possible.

At 01:24 PM 1/17/2006, meteoriteplaya_at_comcast.net wrote:
>Hi Bernd & Jeff
>
>It took me quite a long time to figure out &
>remember the difference between the two
>different designations. Here is how I finally
>figured it out. I just "see" the dash as a comma
>H3-4 or H3,H4 and the slash as arrow H3/4 or
>H3<-->H4. If all else fails I just think of Zag
>as it obviously has two different clasts. One is
>dark and one is light. Here is a nice image of
>Zag from Tim Heitz's web site that illustrates
>this point.
>http://www.meteorman.org/Zag.htm One is type 3
>and the other is type 6....thought I can't
>remember which is which. So now quiz yourself
>and see if you understand what the correct
>classification of the Zag H breccia should be. Is it H3-6 or H3/6
>Here is the answer from the MB website http://littlink.com/7qcgn
>
>This brings up another question. Is it possible
>to have a transitional meteorite across more
>than two grades? According to my understanding
>of temperatures required to produce the various
>petrologic grades it would be impossible. The
>reason I ask this is because we do occasionally
>see meteorites with this classification eg Shisr
>010 L4/6 http://littlink.com/zj7p0
>
>Mike
>
>--
>Mike Jensen
>Jensen Meteorites
>16730 E Ada PL
>Aurora, CO 80017-3137
>303-337-4361
>IMCA 4264
>website: www.jensenmeteorites.com
>
> -------------- Original message ----------------------
>From: bernd.pauli_at_paulinet.de
> > Hello Dave and List,
> >
> > 1. Jeff Grossman wrote this in 1998 (private communication)
> > about A?fer 160, classified as an LL3.8-6 chondrite:
> >
> > The hyphen implies a continuous range, and also implies that
> > there is no dominant lithology in the breccia. Acfer 160 could
> > be:
> >
> > a) a type 3 chondrite with a single equilibrated clast found;
> > b) a type 6 chondrite with a single type 3 clast found;
> > c) a mixture of types 3, 4, 5, and 6 material;
> > d) a light-dark breccia with mostly comminuted matrix
> > and only a few clasts, including type 3 and 6 ones.
> >
> > 2. David Weir once wrote to the List:
> >
> > "Based on the conventions followed by the NomCom as stated in the intro
> > to every Bulletin, for chondrite groups, petrologic types, shock stages,
> > and weathering grades, slashes (e.g., H5/6) indicate transitional assign-
> > ments.
> >
> > Hyphens in petrologic type assignments for chondrites (e.g., H5-6) indicate
> > the range of types observed in breccias.
> Group names such as "L(LL)" indicate
> > uncertain assignments, with the less probable group in parentheses."
> >
> > Regards,
> >
> > Bernd
> >
> > ______________________________________________
> > Meteorite-list mailing list
> > Meteorite-list_at_meteoritecentral.com
> > http://six.pairlist.net/mailman/listinfo/meteorite-list
>______________________________________________
>Meteorite-list mailing list
>Meteorite-list_at_meteoritecentral.com
>http://six.pairlist.net/mailman/listinfo/meteorite-list

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 17 Jan 2006 02:01:48 PM PST