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
