Hi, list - I've had the great opportunity to work on a chondrite with phlogopite - the R chondrite LAP 04840. This weirdo has ~ 15% of amphibole, and about 1% phlogopite along with the usual olivine and pyroxene.
http://www.lpi.usra.edu/meetings/lpsc2007/pdf/1309.pdf Funny things are everywhere! Allan Treiman P.S. Biotite mica includes the Mg-rich end-member phlogopite, and the Fe-rich end-member annite. -----Original Message----- From: [EMAIL PROTECTED] on behalf of Mr EMan Sent: Sun 2/25/2007 5:03 PM To: [EMAIL PROTECTED]; [email protected] Cc: Subject: Re: [meteorite-list] Mica in meteorites....was Comet McNaught andSodium --- [EMAIL PROTECTED] wrote: > The CV3 chondrite Grosnaja contains sodium > phlogopite, a phyllosilicate Well if this is so, a long standing "factoid" in the world of meteorites falls with this finding: "Mica does not occur in meteorites". Seems some meteorites DO contain mica, and a mineral species of mica that would not have been anticipated in Bowen. The micas biotite and muscovite appear in Bowen's reaction series while philogopite does not (given normal availability of iron). Only in an iron poor setting does philogopite form. In this case a potassium substitution by sodium has also occurred. Phlogopite (K,Mg3AlSi3O10 (F,OH)2)is the end member of the phlogopite biotite series of mica-- usually associated with metamorphism of marbles, igneous intrusions such as kimberlites of diamond fame, or found in certain magnesium rich pegmaties-- even in basalt. These are not the sources one thinks of for carbonaceous meteorites. Elton ______________________________________________ Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
