[meteorite-list] Crystals in Lunar Meteorites...?
From: Thunder Stone <stanleygregr_at_meteoritecentral.com>
Date: Thu, 30 Dec 2010 08:55:14 -0800 Message-ID: <SNT117-W65FDC70F8F2332C6AE090ED2030_at_phx.gbl> Thanks Randy: That answers my question. Perhaps 2011 will be the year when the first lunar is found in North America. Good luck to all out there. Greg S. ---------------------------------------- > Date: Thu, 30 Dec 2010 09:10:32 -0600 > To: meteorite-list at meteoritecentral.com > From: korotev at wustl.edu > Subject: Re: [meteorite-list] Crystals in Lunar Meteorites...? > > Greg; > > Most lunar rocks are impact breccias - rocks made up of bits and > pieces of older rocks. The pieces are called clasts and they may be > suspended in a matrix of crystallized impact melt, glass, or > shocked-compressed smaller clasts. Big clasts are fragments of > rocks. The smaller clasts are typically single mineral grains. It's > not uncommon to see clasts of "breccias in breccias in > breccias." Often, the clasts are cracked and bent as a result of > shock (visible in thin section). These effects also destroy the > transparency. It would be rare to see an attractive mineral clast > with a hand lens on the broken surface of a lunar breccia. Keep in > mind that the ancient lunar highlands is ~80% plagioclase and the > rest is mainly pyroxene and olivine. Plag doesn't take well to being > beat up. You're most likely to see an olivine crystal, but it won't > be very big. > > There are two coarse-grained basalts among the lunar meteorites, > almost certainly source-crater paired. > > http://meteorites.wustl.edu/lunar/stones/mil05035.htm > http://meteorites.wustl.edu/lunar/stones/asuka881757.htm > > They show little evidence of having been affected by impacts (other > than the obvious - they were found on Earth!). As a consequence, > they have big crystals, by lunar standards. > > Small olivine grains are obvious on NWA032/479 > > http://meteorites.wustl.edu/lunar/stones/nwa0032.htm > > Oh, and a petrographically inclined colleague reminded me yesterday > that it's "crossed nicols," not "nichols," and that the metal in > lunar breccias is, in fact, crystalline, though a bit opaque. > > Randy Korotev > > > At 06:19 PM 2010-12-29 Wednesday, you wrote: > > >Thank you Larry - Sometimes you just can't get your thoughts to the > >fingertips. > > > >Greg S. > > > >---------------------------------------- > > > To: stanleygregr at hotmail.com; meteorite-list at meteoritecentral.com > > > Subject: Re: [meteorite-list] Crystals in Lunar Meteorites...? > > > Date: Wed, 29 Dec 2010 18:51:46 -0500 > > > From: thetoprok at aol.com > > > > > > > > > Hi Greg, Randy, List, > > > > > > I have been wondering the same thing since I've recently cut a few of > > > my lunar suspects recently. To put Greg's question a little different, > > > do lunar meteorites ever have crystaline shapes? Can you see with the > > > naked eye or a loupe actual crystal structures like 6 sided or 8 sided > > > crystals? > > > > > > Sincerely, > > > Larry Atkins > > > IMCA # 1941 > > > Ebay username alienrockfarm > > > www.poisonivycontrolofmichigan.com > > > > > > > > > -----Original Message----- > > > From: Thunder Stone > > > To: korotev at wustl.edu; meteorite-list at meteoritecentral.com > > > Sent: Wed, Dec 29, 2010 11:55 am > > > Subject: Re: [meteorite-list] Crystals in Lunar Meteorites...? > > > > > > > > > Thanks Randy:It does to some degree and thanks for the links.I keep > > > reading that lunar rocks contain "clasts," which I interpret as a > > > grouping of crystals mashed together from a previous rock, and not > > > individual crystals. I also read "grains" too.Let me put it another > > > way: Do lunar rocks ever contain large crystals of feldspar or pyroxene > > > like you may see in granite or a pegmetite? I unfortunately only have > > > one very small lunar and have only seen others briefly.I'm convinced if > > > a lunar has lost its fusion crust - it would be very difficult to > > > identify when found.Greg S.----------------------------------------> > > > Date: Wed, 29 Dec 2010 13:05:38 -0600> To: > > > meteorite-list at meteoritecentral.com> From: korotev at wustl.edu> Subject: > > > Re: [meteorite-list] Crystals in Lunar Meteorites...?>> Greg:>> All > > > lunar meteorites contain mineral crystals. The basalts (both> breccias > > > and unbrecciated) are composed mainly of crystals of> pyroxene and > > > plagioclase feldspar. Some contain olivine, and all> contain minor > > > ilmenite and related iron-titanium minerals. The> feldspathic breccias > > > are largely crystalline. The only> noncrystalline material is glass and > > > a little metal. "Crushed rock"> is crushed crystalline material. In > > > some lunar meteorites the> plagioclase has been shock converted to > > > maskelynite which,> technically, isn't a crystal but more like glass.>> > > > Put another way, in photomicrographs of lunar meteorites (or any> rock) > > > under "cross-polarized light" (NOT "plane polarized light") or> > > > "crossed nichols," any and all non-black material is crystalline.>> > > > There are some here:>> > > > http://curator.jsc.nasa.gov/antmet/PDFFiles/B07_LAP02205v3.pdf < basalt > > > >> http://curator.jsc.nasa.gov/antmet/PDFFiles/F23_GRA06157v3.pdf <> > > > feldspathic breccia >> > > > http://curator.jsc.nasa.gov/antmet/PDFFiles/F24_LAR06638v3.pdf <> > > > feldspathic breccia >> > > > http://curator.jsc.nasa.gov/antmet/PDFFiles/M07_MET01210v3.pdf <> > > > basaltic breccia >>> Does this answer your question?>> Randy > > > Korotev>>>>>>> At 11:59 AM 2010-12-29 Wednesday, you wrote:>> >List:> > > > >> >I hope everyone had a prosperous and joyful Holiday Season.> >> >I > > > was wondering something:> >> >Do lunar meteorites ever contain > > > crystals? Or are the just crushed> >rock and lunar soil compacted > > > together? From what I've been able to> >find is that any basalt type > > > rock containing white feldspar that are> >crystals or if there is > > > opaque crystals (ilmenite or> >magnetite...etc.), then it cannot be > > > lunar, is this true? Are there> >some cases where you could find > > > crystals within a lunar rock?> >> >Much Thanks and everyone have a > > > happy New Year.> >> >Greg S.> >> > > > >______________________________________________> >Visit the Archives > > > at> >http://www.meteoritecentral.com/mailing-list-archives.html> > > > >Meteorite-list mailing list> >Meteorite-list at meteoritecentral.com> > > > >http://six.pairlist.net/mailman/listinfo/meteorite-list>> > > > ______________________________________________> Visit the Archives at > > > http://www.meteoritecentral.com/mailing-list-archives.html> > > > Meteorite-list mailing list> Meteorite-list at meteoritecentral.com> > > > http://six.pairlist.net/mailman/listinfo/meteorite-list > > > ______________________________________________Visit the Archives > > > at > > > http://www.meteoritecentral.com/mailing-list-archives.htmlMeteorite-list > > > > > > mailing > > > listMeteorite-list at meteoritecentral.comhttp://six.pairlist.net/mailman/li > > > > > > stinfo/meteorite-list > > > > > > >______________________________________________ > >Visit the Archives at > >http://www.meteoritecentral.com/mailing-list-archives.html > >Meteorite-list mailing list > >Meteorite-list at meteoritecentral.com > >http://six.pairlist.net/mailman/listinfo/meteorite-list > > ______________________________________________ > Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html > Meteorite-list mailing list > Meteorite-list at meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list Received on Thu 30 Dec 2010 11:55:14 AM PST |
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