[meteorite-list] Re: PAC vs Type-7.. -confusing

[S. Ralew]

Dear List,

regarding the answer of Jeff Grossman to the question of Martin Altmann (H7
vs. PAC) I have some small remarks. When I had read the new MetBull, I
noticed some interesting classifications. The previous classifications of
NWA 2353, 2635 as H7 chondrite are obvious changed to a ungrouped achondrite
only because of different oxygen isotope results (?). And another possibly
paired meteorite, NWA 3145, is classified as primitive achondrite. Jeff had
written that "Type 7 chondrites..are NOT primitive achondrites", but if I
read the results of NWA 2635, I wonder how close a H7 classification is
actual on a achondrite or PAC classification. However, I also would prefer
the description as an achondrite instead of H- or L7. The description as H7
or L7 is not very stisfying because these meteorites have a totally
recristallized structure without any chondrules or relict chondrules. If
it`s permitted for non-scientist (like me) I would suggest a description as
"H- or L related achondrites".
Or would this be too simple?;-)

At the following link I have posted some photos of highly equilibrated
chondrites and the difference between Type 6 and Type 7.
http://www.meteoriten.com/h7.html

Best regards,
Stefan

I.M.C.A. Member#3368