[meteorite-list] Unknown irons at ASU

From: Jason Utas <meteoritekid_at_meteoritecentral.com>
Date: Fri, 11 Feb 2011 12:42:55 -0800
Message-ID: <AANLkTik8y-ddX2cHQji7Z-CWkjXUcdqikhhvqotfsvXx_at_mail.gmail.com>

Hello All,
Iron number one is not Tafrawhet (NWA 860).
The expression of widmanstatten patterns on irons' cut surfaces is
governed by how a given iron is cut relative to the iron's internal
octahedral structure. When cut parallel to the 001 miller indicatrix
of the taenite octahedrons, they express a cubic, "blocky" structure:

http://en.wikipedia.org/wiki/File:Cutting_the_octaedron.gif

For a great example of this, check any Cape York slices you might
have; for some reason, most, if not all, of the Cape York on the
market was cut like this.

#1) Far too fresh to be your average Gibeon. While it *could* be
Gibeon based on the pattern, it looks a little off, and the outer edge
of that slice looks very fresh/possibly fusion crusted. Some Gibeons
have fusion crust, but it's occurrence is so rare that I would
hesitate before calling this slice Gibeon. I like Mirko's guess of
Page City. I've seen photos of the main mass, and it was quite fresh,
with a similar pattern. But I wouldn't consider that adequate
evidence for determining what it is. If the size/shape matches up,
maybe then...

- What is certain is that it's not a plessitic octahedrite like Taza.

#2) Now there's a good match for Tafrawhet if I've ever seen one. The
main mass has a crack running down the middle, and it even has a thin
black line running at an angle to the pattern - just like this slice!
And a globby troilite inclusion *just like the one pictured* I can
only assume that Matt mistook #2 for #1, because I think that #2 is
actually a slice of NWA 860.

Here's one:

http://www.arizonaskiesmeteorites.com/AZ_Skies_Links/Tafrawet/

Note the crack I mentioned -- also visible in this slice -- and the
shape matches up as well! -- And that black line running at an
angle!!! I'd say this one's in the bag.

#3) I've seen plenty of irons that look similar - best bet would
probably be to do as some others have said and peruse Buchwald hoping
to find something that looks good.

#4) Yeah, talk about a dead ringer for Tambo Quemado, but...you say
it's from an 1800's collection. Smith's Mountain? Sure...

Best of luck -- glad I could help out with #2 anyways.
Regards,
Jason

On Fri, Feb 11, 2011 at 7:58 AM, <mail at mhmeteorites.com> wrote:
> Hi Mirko
> I made a mistake. 1 is what I meant to call Gibeon, but yes it does look like Page City. I see what you mean. ?And the slices of Page City were about 15 cm across, just like the one in the photo.
>
> No. 2 is what I meant to call NWA. This looks very much like the cut face of the material Ali had a few years back. I would wager a beer on it!
> Matt Morgan
> ------------------------
> Matt Morgan
> Mile High Meteorites
> http://www.mhmeteorites.com
> P.O. Box 151293
> Lakewood, CO 80215
>
> -----Original Message-----
> From: Mirko Graul <m_graul at yahoo.de>
> Sender: meteorite-list-bounces at meteoritecentral.com
> Date: Fri, 11 Feb 2011 15:13:15
> To: Laurence Garvie<lgarvie at cox.net>; <meteorite-list-bounces at meteoritecentral.com>; <meteorite-list at meteoritecentral.com>; <mail at mhmeteorites.com>
> Subject: Re: [meteorite-list] Unknown irons at ASU
>
> Dear Matt,
>
> To #1 , please see the small gaps in the iron.
> This is typical for Page City and I know of no other iron of this type with this feature.
> I have almost all NWA iron in the collection.
> Such is not known to me.
> Please look to the Jim Schwade Collection catalog on page 59.
> I think the slice from the ASU collection is a full slice of the same endcut.
> And #2 sorry, but this is never Gibeon.
> In the photo is a medium or coarse octahedrite.
>
> Best regards Mirko
>
>
>
> Mirko Graul Meteorite
> Quittenring.4
> 16321 Bernau
> GERMANY
>
> Phone: 0049-1724105015
> E-Mail: m_graul at yahoo.de
> WEB: www.meteorite-mirko.de
>
> Member of The Meteoritical Society
> (International Society for Meteoritics and Planetery Science)
>
> IMCA-Member: 2113
> (International Meteorite Collectors Association)
>
>
> --- mail at mhmeteorites.com <mail at mhmeteorites.com> schrieb am Fr, 11.2.2011:
>
>> Von: mail at mhmeteorites.com <mail at mhmeteorites.com>
>> Betreff: Re: [meteorite-list] Unknown irons at ASU
>> An: "Laurence Garvie" <lgarvie at cox.net>, meteorite-list-bounces at meteoritecentral.com, meteorite-list at meteoritecentral.com
>> Datum: Freitag, 11. Februar, 2011 15:31 Uhr
>> #1 is identical to the NWA iron that
>> Ali Hmani has been selling for the past several years. It is
>> from NWA (not Taza) but the name or number escapes me.
>> This slices had the same blocky look to it.
>>
>> #2 Gibeon
>>
>> #3 Looks like Cooper, same shape and a finest pattern that
>> has sort of a ghostly look to it.
>>
>> #4 as Mike said, that is Smith's Mountain.
>>
>> Matt Morgan
>> ------Original Message------
>> From: Laurence Garvie
>> Sender: meteorite-list-bounces at meteoritecentral.com
>> To: meteorite-list at meteoritecentral.com
>> Subject: [meteorite-list] Unknown irons at ASU
>> Sent: Feb 10, 2011 10:22 PM
>>
>> I found four unlabeled iron meteorite slices in the
>> collection at Arizona State University.? They can be
>> seen at
>>
>> www.flickr.com/photos/meteorite_scientist/sets/72157625897257655/
>>
>> If anyone recognizes any of the slices then please let me
>> know at lgarvie at asu.edu
>>
>> Thanks
>>
>> Laurence
>> CMS
>> ASU
>>______________________________________________
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>> ------------------------
>> Matt Morgan
>> Mile High Meteorites
>> http://www.mhmeteorites.com
>> P.O. Box 151293
>> Lakewood, CO 80215
>>______________________________________________
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>
>
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Received on Fri 11 Feb 2011 03:42:55 PM PST