Hi Jason, All, Not classed as a silicated iron but...
I have a nice end cut of Portales valley with about a 2:1 silicate, iron mix that shows an intriguing mix of fusion crusts flowing one into the other. Graham, UK ---- Jason Utas <[email protected]> wrote: > Carl, All, > Wow, thanks for that...hum. > Right - I think people are confusing rarity with desirability, market > value, and collector availability, when these are all really distinct > terms. > Right, it's all about O-isotopes now, but I'm not really sure why - it > seems to me that chemistry should be just as important...surely there > could have been parent bodies forming in the same general areas as > each other that were distinct bodies, but that, due to their relative > proximity, have similar or identical O-isotope values. I don't know - > maybe that is how we group things...seems illogical to me, though. > > The trouble with "fusion crust..." > If I recall, a while back, Elton made some strange comments about a > fusion crust having to be composed of siliceous material and > impurities such as oxides etc. He argued that, because the crust that > forms on irons lacks silicates, it is not a true fusion crust. > > The consensus of the list was that the crust that forms on irons may > be chemically distinct from the crust that forms on stones, but it is > for all intensive purposes analogous in pretty much every way to the > stony version, so we might as well call them the same thing. > > I think the reason we don't see much in the way of fusion crust on > silicated irons is because, well, there aren't many fresh silicated > irons around. There are plenty of examples of crusted irons - and > with just over 50 iron falls, some of which are accessible to > collectors, well, they're there to be seen. I don't know how many of > those ~50 iron falls are silicated, but I do know one thing - of all > of them, Udei Station's the only one that's available in any real > quantity, and I've never seen an example with good crust. I don't > think that's because it didn't form a fusion crust - I just think that > such pieces aren't widely available, so they remain out of our field > of view, for the most part... > > Think of Estherville, things like that. They're made of a pretty even > mix of iron and stone and they still form a fusion crust. > > I have a ~4.7g 1/2 end of Bencubbin that shows some pretty spectacular > warty fusion crust...I can get some pictures up if you'd like. I > figure that's about 1/2 stone and metal as well, so...yeah. > > Regards, > Jason > > On Wed, Nov 18, 2009 at 10:26 AM, <[email protected]> wrote: > > Jason, I would first like to say that if there were an award for most > > helpful and kind on this list you would be the winner. > > I truly believe you offer more good information than anyone else on this > > list. That says a lot because there are a ton of great people on this list. > > And I want to thank you for all you do. You are a tremendous person. > > > > I think you are 100% correct with this evaluation as you describe it. But, > > There is something to desirability / Valuable in the formula of "rare". > > Just because something is rare does not mean it is desirable or valuable. > > To me rarely is irrelevant if not desirable. As you correctly point out. > > Who cares about your L6. So, to me the rarest meteorite that has those > > things has got to be the meteorite that every collector wants the most. > > That said it would be a subjective call but for me it would be ALH 84001. > > Lastly, Your reference to Jeff Grossman are correct but I notice that > > Oxygen isotopes rule in this biz. If the air matches , then that is where > > it is from and therefore that is what it is. > > A recent example of this is GRA 06128. They are calling it a brachinite > > based on Isotopes even though it is not related in other ways to the brach > > clan. So, apparently the where it is from needs more specific categories > > like Mars now has four different categories. > > Anyway, I wanted to thank you for all your information. I know I had never > > seen actual fusion crust on any iron before yours. I have seen a lot of > > impostors but yours is truly the real deal. > > Has anyone ever studied that crust to determine what it is made up of? It > > seems from an earlier thread that the crust must be a mixture of the > > silicates within this meteorite. Because most other irons without silicates > > within them do not seem to leave a true fusion crust like your sikhote did? > > Thanks Carl > > -- > > Carl or Debbie Esparza > > Meteoritemax > > > > > > ---- Jason Utas <[email protected]> wrote: > >> Hello Sonny, All, > >> I've often thought about such a term - "the rarest meteorite." > >> The rarest meteorite would of course be smallest ungrouped meteorite, > >> for one could feasibly conceive of a 1-2g unique meteorite. When a > >> new type is named, however, a hype generally surrounds it - rather > >> like the olivine diogenite craze of a few years ago, or the confusion > >> surrounding Bencubbinites, and other poorly defined types of > >> meteorites. > >> The simple fact of the matter is that there meteorites are too often > >> categorized by our current system into associations and groups into > >> which they fit rather poorly; Jeff Grossman states as much in the last > >> thread surrounding the poor chemical and isotopic relationships > >> between many basaltic meteorites deemed "eucrites." > >> But regardless of this fact, a simple truth remains. There are > >> countless ungrouped meteorites and several Kakangari-type meteorites, > >> so while they may be one of the least common "types," they are by no > >> means examples of the "rarest" meteorite known. > >> Regards, > >> Jason > >> > >> On Tue, Nov 17, 2009 at 6:12 PM, <[email protected]> wrote: > >> > Hi Bernd and list, > >> > > >> > Would this be one of the rarest meteorites ever found? If not, what > >> > meteorite would be? > >> > > >> > Thanks, > >> > Sonny > >> > > >> > > >> > -----Original Message----- > >> > From: [email protected] > >> > To: [email protected] > >> > Sent: Tue, Nov 17, 2009 1:12 pm > >> > Subject: [meteorite-list] Photo of a K-chondrite > >> > > >> > > >> > > >> > > >> > > >> > > >> > > >> > Hi Greg and List, > >> > > >> > Hardly any photos of Kakangaris exist. You'll find one on David > >> > Weir's excellent website: http://www.meteoritestudies.com/ > >> > > >> > Click on chondrites and then scroll down to Kakangari! > >> > > >> > Thin section pics of Kakangari can be found here (on pages 202-205): > >> > > >> > D.S. LAURETTA, M. KILLGORE (2005) A Color Atlas of Meteorites in Thin > >> > Section > >> > (Golden Retriever Publications and Southwest Meteorite Press, ISBN > >> > 0-9720472-1-2, 301 pp.). > >> > > >> > > >> > Best wishes, > >> > > >> > Bernd > >> > > >> > ______________________________________________ > >> > http://www.meteoritecentral.com > >> > Meteorite-list mailing list > >> > [email protected] > >> > http://six.pairlist.net/mailman/listinfo/meteorite-list > >> > > >> > > >> > > >> > > >> > > >> > > >> > ______________________________________________ > >> > http://www.meteoritecentral.com > >> > Meteorite-list mailing list > >> > [email protected] > >> > http://six.pairlist.net/mailman/listinfo/meteorite-list > >> > > >> ______________________________________________ > >> http://www.meteoritecentral.com > >> Meteorite-list mailing list > >> [email protected] > >> http://six.pairlist.net/mailman/listinfo/meteorite-list > > > ______________________________________________ > http://www.meteoritecentral.com > Meteorite-list mailing list > [email protected] > http://six.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ http://www.meteoritecentral.com Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
