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

[Jeff Grossman]

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 Açfer 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
> >
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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