[meteorite-list] Mesosiderite Classification Clarifications

[Greg Hupe]

Dear David, Walter and list members,

Regarding subclassifications of mesosiderites, here is what Dr. Bunch has 
replied to David's and Walter's inquiries of our description of our new 
mesosiderite, NWA 2711:

David Weir wrote:
"For those of us who are strictly type collectors, I guess I'm not the
only one, are they not making the extra effort any longer to determine a
metamorphic subclassification for mesosiderites? I haven't noticed a
subclassification on any since the 2C was released over two years ago."
Dr. Bunch's reply:
"David is correct - even the one that is used is not accepted by NomCom, 
e.g., the meso -C mesosiderite of a few years back was not accepted as such 
even though it had < 5 vol % plagioclase."

Walter Branch wrote:
"Really?  He said it was 'very unique'. Would you please ask Dr. Bunch to 
clarify the term 'very unique' "
Dr. Bunch replies (stating he does not remember adding "very" during our 
phone conversation a few weeks ago so my apologies to Dr. Bunch if I 
misquoted him):
"...the uniqueness (of NWA 2711) is due to the unusual amount of phosphate 
or merrillite crystals in the unrecrystallized pyroxenes (megacrysts)."

Hope this helps in understanding the "uniqueness" of our new mesosiderite, 
NWA 2711.

Best regards,

Greg Hupe
The Hupe Collection
naturesvault (eBay)
gmhupe at tampabay.rr.com
IMCA 2185