Here a pic with a troilite in Sikhote.
http://it.geocities.com/mcomemeteoritecollection/SikhoteAlin.JPG
I would guess, that it would have been rather a lenticular troilite torn
out. Schreibersite surrounding troilite or alone, wouldn't mark such a sharp
border in my opinion, especially not in Sikhote, where we find it often in
large skeletons of crystals.
But where I have problems of understanding, is, how such a circular shape
could have survived in a shrapnel at those high forces at the impact?
Wouldn't be some deformation to be expect, as e.g. it happened to this
inclusion in a shrapnel?
http://www.meteorite.com/gallery/mh_sikhote-11.jpg
Unfortunately now the pics from that auction seems not to be available
anymore. Weren't there other regular shaped pits connected to that hole?
To me it looks like a later deformation.
Just a guess,
Buckelboo
-Ursprüngliche Nachricht-
Von: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Im Auftrag von Jeff
Kuyken
Gesendet: Mittwoch, 28. Juni 2006 11:23
An: Meteorite-list@meteoritecentral.com; [EMAIL PROTECTED]
Betreff: Re: [meteorite-list] Sikhote-Alin Question
That would make sense Bernd. I initially noticed that it looks like two of
them right next to each other.
formed parallel cylinders 10-40 mm in diameter
Cheers,
Jeff
- Original Message -
From: [EMAIL PROTECTED]
To: Meteorite-list@meteoritecentral.com
Sent: Wednesday, June 28, 2006 6:38 AM
Subject: [meteorite-list] Sikhote-Alin Question
Eric wrote:
Anyone want to take a stab at what it might be.
I have no good explanations. Here is a link to
the auction
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemcategory=3239item=2300021628
91
OK, ... taking a stab at what it might be. If it is NOT one of those
impact-produced surface craters that McHone and M. Killgore describe
in Impact-produced surface craters on Sikhote-Alin irons (cp. MAPS
33-4, Supplement, 1998, p. A101), it might be troilite surrounded by
schreibersite + swathing kamacite.
Buchwald wrote about Sikhote-Alin:
Troilite occurs in minor amounts, mostly associated with the
schreibersite skeleton crystals which in many instances may have
nucleated upon the troilite. The troilite forms 1-10 mm nodules
and lenticular bodies. In most cases it forms the central part
of cm-sized, intricate, lace-like textures where schreibersite
filaments and hieroglyphs radiate from the troilite in structures
that suggest coarse-grained eutectics (+). Similar structures are
present in, e.g., Sao Juliao, Sandia Mountains and S a n t a
L u z i a*.
.., and on p. 1074, Buchwald wrote about Santa Luzia*:
BUCHWALD V.F. (1975) Iron Meteorites (Univ. of
California, 1975, Vol.3, excerpts from p. 1074):
Not only is the troilite elongated parallel to the present exterior
surface,
but the schreibersite-metal eutectics (+) associated with it also appear to
have formed parallel cylinders 10-40 mm in diameter. Later, swathing
kamacite
has grown around these cylinders in the solid state to form concentric
shells,
5-15 mm thick. Troilite forms the central part of the cylinders, but, since
it pinches and swells irregularly, it may or may not be present in a given
section perpendicular to the cylinders.
(+) McSWEEN H.Y. (1999) Meteorites and Their Parent Planets
Cambridge University Press, Glossary, p. 290): the liquid that
occurs at the lowest temperature in a chemical system.
So, maybe, we are looking at a cross-section of such a cylinder.
Well, probably not quite as interesting as the ongoing discussion
about fraudulent trade practices, but, anyway, ... my stab ;-)
Bernd
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