[meteorite-list] Sikhote-Alin Question

From: Martin Horejsi <accretiondesk_at_meteoritecentral.com>
Date: Tue Jul 11 14:22:24 2006
Message-ID: <9c2f96d20607111122n6fe35be5tdcca4b49a45e6ea9_at_mail.gmail.com>

Hi All,

I knew I had seen that feature somewhere, but I could not remember at the time.

Anyway I found it. It was in a 0.334g oriented Bensour individual I
have in my collection.

Here are three pics of the piece. While on an entirely different
scale, both in size and class, it does have a striking resemblance to
the feature in the Sikhote-Alin that caused this thread.

http://www.geocities.com/planetwhy/bensour1.jpg

http://www.geocities.com/planetwhy/bensour2.jpg

http://www.geocities.com/planetwhy/bensour3.jpg

Happy contemplating.

Martin




On 27 Jun 2006 20:38:24 UT, bernd.pauli_at_paulinet.de
<bernd.pauli_at_paulinet.de> wrote:
> 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?ViewItem&category=3239&item=230002162891>
>
> 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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Received on Tue 11 Jul 2006 02:22:20 PM PDT