[meteorite-list] Patterns in Sikhote-Alin

From: meteoriteshow <meteoriteshow_at_meteoritecentral.com>
Date: Thu Apr 22 10:17:48 2004
Message-ID: <00e901c3c3c8$19af4be0$9bc5933e_at_monordinateur>

Dear David,

Melting while crossing the atmosphere is "superficial". Meteorites lose a
major part of their weight (less for irons than stones) that burns away to
ashes, but the inside of the meteorite remains at space temperature (i.e.
abour -270°C). This is the main reason whay they often break into fragments
in the atmosphere (because of high stresses due to temperature difference
btween the inside and the "burning skin"), and actually this is what
happened to Sikhote Alin, providing numerous fragments. As almost of all
them show regmaglypts, this means that it happened in the high atmosphere,
high enough to allow the fragments to keep on burning for a while. But the
inside did not melt. For smaller fragments, the inside most probably heated
up, but not to melting point.
This is my understanding, and should I be wrong, please do not heasitate to
let me know as I'm always open to learning more!

Frederic Beroud
www.meteoriteshow.com
IMCA #2491
----- Original Message -----
From: "David Hathaway" <dhathaway_at_peak.org>
To: <meteorite-list_at_meteoritecentral.com>
Sent: Tuesday, December 16, 2003 7:28 AM
Subject: [meteorite-list] Patterns in Sikhote-Alin


> I am a little curious about something.....
>
> I heard that the sikhote-alin meteorites have a Widmanstatten Pattern
> although large and difficult to see.
>
> I have also heard that the regmaglypts are created when a molten piece
cools
> while airborne.. As nearly all the fragments I have seen have regmaglypts
I
> assume all these pieces have been molten.
>
> So after melting and recooling on Earth do they really maintain the
pattern
> or is it only present on pieces large enough not to melt?
>
>
>
> ______________________________________________
> Meteorite-list mailing list
> Meteorite-list_at_meteoritecentral.com
> http://www.pairlist.net/mailman/listinfo/meteorite-list
>
Received on Tue 16 Dec 2003 06:31:07 AM PST