Hi all, Thanks Jeff and Doug.
Sorry Ted, I've been out of town and haven't followed any other similar conversation so I wasn't aware it was a touchy subject. However, since we're here....... I still have one last question - actually I need advice on what to call these slices when I advertise them for sale. Jeff says (and Ted seems to agree) "I think the Bunch et al.'s conclusion that NWA 3100 is a CR6 is the best we have right now, but I think you still have to think of this as preliminary. I bought this collection to sell so.... Can I call it a CR6 when I sell it or should I call it a primitive achondrite? On Mon, Dec 5, 2011 at 8:45 PM, John Lutzon <[email protected]> wrote: > > Thank you Jeff, > > Believe it or not, you enlightened my small small knowledge about this. > > Further sales of "metachondrite" terminology is hereby suspended until Ted's > posterier heals. > > Sorry, just had to, John. > > ----- Original Message ----- From: "Ted Bunch" <[email protected]> > To: "Jeff Grossman" <[email protected]>; > <[email protected]> > Sent: Monday, December 05, 2011 10:00 PM > Subject: Re: [meteorite-list] Primitive Achondrite Question > > > >> Well stated Jeff and I agree! Thank you. There is the thing about >> "metachondrite" terminology, but we shall leave this "dead horse" alone >> for >> the time being. >> >> Two of these unremitting classification issues in 3 days is much too much >> for me in one week, especially when my butt is tied to both of them. >> >> Ted >> >> >> On 12/5/11 7:02 PM, "Jeff Grossman" <[email protected]> wrote: >> >>> Type 7 is considered by most of those who use it to represent the >>> highest degree of thermal metamorphism that a chondrite can experience >>> without melting. As implied in that first sentence, some petrologists >>> don't distinguish these from type 6. The term "primitive achondrite" is >>> widely taken to be the next stage: you make them when a chondrite >>> partially melts, and the process of crystal-melt separation begins. The >>> "primitive" part says that the bulk composition is still fairly close to >>> chondritic. But these definitions are not used by everybody, and you >>> will get arguments about them. >>> >>> Clearly, the "LL" part of an LL7 classification for NWA 3100 is >>> unlikely. O isotopes are below the terrestrial fractionation line, >>> which basically rules it out. So it is not an LL7. Bunch has shown >>> that the O isotopes are closer to CR chondrites. >>> >>> The hard part is the type 7 vs. primitive achondrite distinction. Bunch >>> et al.'s 2005 and 2008 LPSC abstracts do not report anything in NWA 3100 >>> that I take as evidence of melting or differentiation. So I don't see >>> any reason to call these primitive achondrites, at least not based on >>> these findings. I think the Bunch et al.'s conclusion that NWA 3100 is >>> a CR6 is the best we have right now, but I think you still have to think >>> of this as preliminary. Ted can correct me, but I think it was actually >>> the nomcom that pushed for calling this a PAC, amid controversy on the >>> committee. >>> >>> Jeff >>> >>> >>> On 12/5/2011 8:23 PM, Ruben Garcia wrote: >>>> >>>> Hi all, >>>> >>>> I just bought a smallish collection and several of the slices that >>>> came with are NWA 3100. Mike Farmer's card was included and lists NWA >>>> 3100 as an LL7. The Met-Bul calls NWA 3100 a Primitive achondrite - >>>> not an LL7. >>>> >>>> My question is this, >>>> >>>> Does LL7 denote a particular Primitive achondrite? If so which one? If >>>> not then what type is this? >>>> >>>> BTW - I think Ted Bunch did the classification >>>> >>> >>> ______________________________________________ >>> Visit the Archives at >>> http://www.meteoritecentral.com/mailing-list-archives.html >>> Meteorite-list mailing list >>> [email protected] >>> http://six.pairlist.net/mailman/listinfo/meteorite-list >> >> >> >> ______________________________________________ >> Visit the Archives at >> http://www.meteoritecentral.com/mailing-list-archives.html >> Meteorite-list mailing list >> [email protected] >> http://six.pairlist.net/mailman/listinfo/meteorite-list >> > > ______________________________________________ > Visit the Archives at > http://www.meteoritecentral.com/mailing-list-archives.html > Meteorite-list mailing list > [email protected] > http://six.pairlist.net/mailman/listinfo/meteorite-list -- Rock On! Ruben Garcia Website: http://www.mr-meteorite.net Articles: http://www.meteorite.com/blog/ Videos: http://www.youtube.com/profile?user=meteorfright#p/u ______________________________________________ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
