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

From: meteoriteplaya_at_comcast.net <meteoriteplaya_at_meteoritecentral.com>
Date: Tue Jan 17 13:24:51 2006
Message-ID: <011720061824.27419.43CD36490005699100006B1B22007354460E970E049F0A9B079D010A9B0A03_at_comcast.net>

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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Received on Tue 17 Jan 2006 01:24:09 PM PST