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
