As I understand this, Alan, you are saying that dunites will succumb to the "weathering" processes of space--the effects of radiation over time, in particular, and they disintegrate before they even make it to the top of the atmosphere. Dunites are notoriously unstable on the surface of the Earth. Perhaps that's their lot in space too. Eric
On Jan 14, 2014, at 8:25 PM, Alan Rubin <aeru...@ucla.edu> wrote: > Iron meteorites tend to break up in the atmosphere at lower depths than stony > meteorites, so I suppose that pallasites would also be better able to survive > transit through the Earth's atmosphere than dunites. But I am guessing that > very few dunites ever make it to the top of the Earth's atmosphere to begin > with. > > > Alan Rubin > Institute of Geophysics and Planetary Physics > University of California > 3845 Slichter Hall > 603 Charles Young Dr. E > Los Angeles, CA 90095-1567 > phone: 310-825-3202 > e-mail: aeru...@ucla.edu > website: http://cosmochemists.igpp.ucla.edu/Rubin.html > > > ----- Original Message ----- From: <pshu...@messengersfromthecosmos.com> > To: "Alan Rubin" <aeru...@ucla.edu>; "Jim Wooddell" > <jim.woodd...@suddenlink.net>; <meteorite-list@meteoritecentral.com> > Sent: Tuesday, January 14, 2014 5:27 PM > Subject: RE: [meteorite-list] Near pure Olivine Meteorite > > > Would they also melt or more correctly ablate off material faster and > more completely > upon entering the earth's atmosphere? > Pete > > >> -------- Original Message -------- >> Subject: Re: [meteorite-list] Near pure Olivine Meteorite >> From: "Alan Rubin" <aeru...@ucla.edu> >> Date: Tue, January 14, 2014 6:54 pm >> To: "Jim Wooddell" <jim.woodd...@suddenlink.net>, >> <meteorite-list@meteoritecentral.com> >> >> >> The question of the dearth of olivine meteorites (asteroidal dunites) has >> been around for a very long time. Most folks have ascribed this paucity as >> being due to the brittle nature of olivine meteorites relative to >> pallasites. Pallasites have relatively long cosmic-ray-exposure ages >> indicating that they can survive the rigors of interplanetary space for a >> rather long while. Eucrites have much shorter CRE ages on average. This >> suggests that if asteroidal dunites are from deep in the mantle, they would >> be in space about as long as the pallasites and not survive because they are >> no tougher than eucrites. >> Alan >> >> >> Alan Rubin >> Institute of Geophysics and Planetary Physics >> University of California >> 3845 Slichter Hall >> 603 Charles Young Dr. E >> Los Angeles, CA 90095-1567 >> phone: 310-825-3202 >> e-mail: aeru...@ucla.edu >> website: http://cosmochemists.igpp.ucla.edu/Rubin.html >> >> >> ----- Original Message ----- From: "Jim Wooddell" >> <jim.woodd...@suddenlink.net> >> To: <meteorite-list@meteoritecentral.com> >> Sent: Tuesday, January 14, 2014 4:05 PM >> Subject: [meteorite-list] Near pure Olivine Meteorite >> >> >> > So, we find pallasites, we find irons, we find chondrites. And, with > the >> > pallasites some are loaded with a lot of olivine. So anyone have any >> > scientific ideas why we don't find near pure olivine meteorites? Or do >> > we?? >> > >> > For the sake of conversation... >> > >> > Jim >> > >> > -- > Jim Wooddell >> > jim.woodd...@suddenlink.net >> > http://pages.suddenlink.net/chondrule/ >> > >> > ______________________________________________ >> > >> > Visit the Archives at http://www.meteorite-list-archives.com >> > Meteorite-list mailing list >> > Meteorite-list@meteoritecentral.com >> > http://six.pairlist.net/mailman/listinfo/meteorite-list >> >> ______________________________________________ >> >> Visit the Archives at http://www.meteorite-list-archives.com >> Meteorite-list mailing list >> Meteorite-list@meteoritecentral.com >> http://six.pairlist.net/mailman/listinfo/meteorite-list > > ______________________________________________ > > Visit the Archives at http://www.meteorite-list-archives.com > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
