[meteorite-list] Sikhote crust-chondrite / Could this be one of the rarest meteorites found?

From: Jeff Kuyken <info_at_meteoritecentral.com>
Date: Thu, 19 Nov 2009 17:41:04 +1100
Message-ID: <711FEC7CFB5445F1B5AC1CFF043AC768_at_JeffPC>

Hi Graham,

I think that's a good example as I have a small endcut of PV that shows
something a little similar too. I don't personally know of any meteorite
that hasn't had some sort of fusion crust. I would expect silicated irons to
have a different fusion crust in the different areas. A little like impact
melts too which also seem to get varying zones and can be a good indication
of what you have. But the coolest crust of all... Aubrites like Aubres and
Norton County! They're something special!

Cheers,

Jeff


----- Original Message -----
From: <ensoramanda at ntlworld.com>
To: "Meteorite-list" <meteorite-list at meteoritecentral.com>; "Jason Utas"
<meteoritekid at gmail.com>
Sent: Thursday, November 19, 2009 10:43 AM
Subject: Re: [meteorite-list] Sikhote crust-chondrite / Could this be one of
the rarest meteorites found?


> 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 <meteoritekid at gmail.com> 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, <cdtucson at cox.net> 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 <meteoritekid at gmail.com> 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, <wahlperry at aol.com> 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: bernd.pauli at paulinet.de
>> >> > To: Meteorite-list at meteoritecentral.com
>> >> > 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
>> >> >
>> >> > ______________________________________________
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>> >> >
>> >> >
>> >> >
>> >> >
>> >> >
>> >> >
>> >> > ______________________________________________
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>> >> >
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Received on Thu 19 Nov 2009 01:41:04 AM PST