As it turns out, it is very easy to see if an OC is type 3.05-3.15. The exsolution of chromite from olivine in type II porphyritic chondrules can be seen in an optical microscope, with the aperture stopped down. It looks like this: https://www.lpi.usra.edu/meteor/get_original_photo.php?recno=5674513. See the little wormy lines? Subdividing these into 3.05, 3.10, and 3.15 does take some work, but you’d be safe classifying them as type 3.1 if this effect is visible.
If a meteorite has black opaque matrix, razor sharp chondrules, and you CAN’T see exsolution in any olivines, the meteorite bears closer inspection to see if it is extra special. Jeff From: Meteorite-list <meteorite-list-boun...@meteoritecentral.com> On Behalf Of Graham Ensor via Meteorite-list Sent: Monday, November 11, 2019 2:38 AM To: Kevin Kichinka <mars...@gmail.com> Cc: meteorite list <meteorite-list@meteoritecentral.com> Subject: Re: [meteorite-list] Fractional Classification of LL3's Hi Kevin, As far as I can make out, talking with other researchers, then it can/will be done but takes extra time and work and thus many just get given the 3 designation rather than do all that work to divide it up even more...although if one is suspected as a 3.00 then I imagine it is worth it or if the presenter of the specimen pays for the time and effort to do the work. Graham On Mon, Nov 11, 2019 at 12:57 AM Kevin Kichinka via Meteorite-list <meteorite-list@meteoritecentral.com <mailto:meteorite-list@meteoritecentral.com> > wrote: Team Meteorite: A couple of years ago it seemed that researchers were no longer going to sub-divide LL3 mets to classifications like 'LL3.05' or 'LL3.10', or I suppose the most primitive one of LL3.0'. Can someone clarify this issue for me? And regards to Zsolt Kereszty while referencing his acquisition of NWA12692 LL3.00 "Here is the MetBull page of the NWA12692 LL3.00 meteorite:" https://www.lpi.usra.edu/meteor/metbull.php?code=70116 ______________________________________________ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com <mailto:Meteorite-list@meteoritecentral.com> https://pairlist3.pair.net/mailman/listinfo/meteorite-list
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