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, [EMAIL PROTECTED] 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: [EMAIL PROTECTED]
> 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
>
> ______________________________________________
> Meteorite-list mailing list
> [email protected]
> http://six.pairlist.net/mailman/listinfo/meteorite-list
______________________________________________
Meteorite-list mailing list
[email protected]
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
______________________________________________
Meteorite-list mailing list
[email protected]
http://six.pairlist.net/mailman/listinfo/meteorite-list
