Dr Ted Bunch did the classification. I have to belive that he knows what he it doing. The pieces are up on my website right now. See them here http://www.meteoriteguy.com/nwa2092.htm http://www.meteoriteguy.com/nwa20922.htm Price is $30.00 gram today only. Mike Farmer ----- Original Message ----- From: "David Weir" <[EMAIL PROTECTED]> To: "Adam Hupe" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Thursday, March 25, 2004 4:11 PM Subject: Re: [meteorite-list] LL7 Chondrites
> Hey Adam, > > Yes, I agree with you. Very perceptive. The two types are mutually > exclusive based on the definition of Dodd. Type 7 ordinary chondrites > were originally defined by Dodd et al. (1975) according to specific > petrographic characteristics. They listed three metamorphic criteria to > distinguish between petrographic types 6 and 7: > > 1.the presence of poorly defined chondrules in type 6, but only relict > chondrules in type 7 > > 2.low-Ca pyroxenes in type 6 contain no more than 1.0 wt% CaO (1.0 wt% = > ~1.9 mol% Wo), but more than 1.0 wt% in type 7; conversely, the CaO > content of high-Ca pyroxenes decreases from type 6 to type 7 > > 3.feldspar grains gradually coarsen to reach a size of at least 0.1 mm > in type 7 > > Perhaps this is one of those confused cases of classification in which > different labs call things by different terminology. Could they have > found both petrographic phases in the stone and used the slash to > indicate this? Who did the classification? > > Regards, > David > > ______________________________________________ > Meteorite-list mailing list > [EMAIL PROTECTED] > http://www.pairlist.net/mailman/listinfo/meteorite-list > ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
