[meteorite-list] Gebel Kamil iron is official now - 1.6 metrictons!?!?

From: Martin Altmann <altmann_at_meteoritecentral.com>
Date: Tue, 13 Jul 2010 19:09:34 +0200
Message-ID: <005201cb22ae$2d42fd90$6502a8c0_at_name86d88d87e2>

Hi Jason,

well and the Sikhote-shrapnels?
Or remember these Canyon Diablos, found on one side of the crater rim, where
the pattern was completely annihilated by heat and which are completely
recrystallized.

If one would had only such examples of Canyon and Sikhote, undoubtedly they
would be given the structural type: ataxite.

(Btw. the Bavarian iron find Inningen, which still hasn't been removed from
the Bulletin, which has identical values like Sikhote, got as structural
type also ataxite, cause it was a shrapnel. ...a Sikhote-like shrapnel,
havig the same trace element data like Sikhote and found without any other
pieces nor any impact structures or pits lying on a road - ouch! That
hurts...).

All I'm telling is, that it might be too early to commit to that structural
type with the Egypt iron, as maybe there will be still found (or examined)
more intact pieces.

Like so many in this thread I know Gebel Kamil only from the loads our
Russian finder kings brought to light and to Ensisheim.

They were all extremely stressed, sharp-edged, tattered and torn frazzles of
iron - just like the shrapnels we all know from Sikhote-Alin.

How distorted and stressed they are, you can observe on the extremely
disturbed and deformed schreibersites in Mirko's slices, if you compare
these to the large, angular skeletonised schreibersite crystals in
Sikhote-individuals or in Guanaco e.g.


You could add also Morasko to your list.

Well, for me - maybe I'm there conservative - a shrapnel is a totally
destroyed and tattered lump of an iron meteorite, which fully has lost its
original structure due to the forces of a major explosion.
I guess, that's why also the military term "shrapnel" was used as an
analogue for this type of iron meteorites.

Those which you mean, which show a partial deformation, I wouldn't call in
my personal use "shrapnels", at best maybe partial shrapnels.
But that depends on one's individual interpretation, I omit,
because "shrapnel" is a not exactly defined term, similar as we have it with
"orientation" or more recently with the "hammer stones".

Best!
Martin




 
 


-----Urspr?ngliche Nachricht-----
Von: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] Im Auftrag von Jason
Utas
Gesendet: Dienstag, 13. Juli 2010 15:23
An: Meteorite-list
Betreff: Re: [meteorite-list] Gebel Kamil iron is official now - 1.6
metrictons!?!?

Hello Mirko, All,
That's just not true at all - plenty of irons have seen plastic
deformation without becoming ataxites.


Seymchan:

http://www.carionmineraux.com/mineraux/Mineraux_Juillet_aout_2008/meteorite_
seymchan_1.jpg

http://www.imca.cc/insights/2007/II06-img/Seymchan.jpg


Henbury:

http://www.minresco.com/meteor/meimages/me606d.jpg


Uruacu:

http://cgi.ebay.com/LOW-PRICE-URUACU-IRON-METEORITE-BRAZIL-END-CUT-804-GMS-/
200446229790?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item2eab86bd1e#ht_1622w
t_906

http://cgi.ebay.com/LOW-PRICE-URUACU-IRON-METEORITE-BRAZIL-END-CUT-514-GMS-/
200421205241?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item2eaa08e4f9#ht_1579w
t_906


- I've also seen examples of similar features in Sikhote-Alin,
Boxhole, Gibeon, and Campo del Cielo.

Plastic deformation due to impact does not result in the complete loss
of widmanstatten pattern. The only plastically deformed ataxites that
lack any true pattern (that I can think of) are Chinga (deformed
schlieren) and this new Egyptian iron, neither of which appear to have
had widmanstatten patterns before entering the atmosphere.

Regards,
Jason

On Tue, Jul 13, 2010 at 5:30 AM, Martin Altmann
<altmann at meteorite-martin.de> wrote:
> But is there a finest octahedrite among the chemical
IAB/IIICD-complex....?
> And are there coarsest octahedrites to be found among the IVAs?
>
> I think, it's quite reasonable, not to give a structural type at that
point
> of time for the Egypt iron, if there were only shrapnels found,
respectively
> analyzed.
> Shrapnels by their nature are always ataxitic.
>
> Or was meanwhile a not so damaged individual found and examined?
>
> Best!
> Martin
>
>
> -----Urspr?ngliche Nachricht-----
> Von: meteorite-list-bounces at meteoritecentral.com
> [mailto:meteorite-list-bounces at meteoritecentral.com] Im Auftrag von Jeff
> Grossman
> Gesendet: Dienstag, 13. Juli 2010 13:48
> An: meteorite-list at meteoritecentral.com
> Betreff: Re: [meteorite-list] Gebel Kamil iron is official now - 1.6
metric
> tons!?!?
>
> "Ataxite" is a structural term, like octahedrite and hexahedrite.
> Modern classification of iron meteorites is based on the chemical group,
> which can tell you something about the parent asteroid. ?The structural
> classification is quasi-independent of the chemical classification,
> inasmuch as members of each structural group can belong to multiple
> chemical groups. ?So "ataxite" has not been replaced with "iron,
> ungrouped." ?Both are correct.
>
> When I used to edit MetBull, the heading on the description of this
> meteorite would have said "Iron, ataxite (ungrouped)", but other editors
> have abandoned this.
>
> Jeff
>
>
>
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Received on Tue 13 Jul 2010 01:09:34 PM PDT