[meteorite-list] Re: Sikhote Question, Impact Pits, Oriented Campo

From: Jim Strope <jim_at_meteoritecentral.com>
Date: Sun Nov 6 11:29:07 2005
Message-ID: <002401c5e2ef$3acb72c0$6401a8c0_at_DJQVK441>

Hi Geoff, Matt and other participants in this thread...........

Geoff, you mentioned that you have seen a few Sikhote-alin that exhibit the
characteristics of a regmaglyped individual as well as shrapnel. Here is an
example of one of my favorite pieces that I acquired years ago. It is an
oriented "individual" with a bottom that looks exactly like shrapnel.

http://209.238.151.128/sa526.htm

Jim Strope
421 Fourth Street
Glen Dale, WV 26038

http://www.catchafallingstar.com

----- Original Message -----
From: "Notkin" <geoking_at_notkin.net>
To: "Meteorite List" <meteorite-list_at_meteoritecentral.com>
Sent: Saturday, November 05, 2005 9:12 PM
Subject: [meteorite-list] Re: Sikhote Question, Impact Pits, Oriented Campo


> Dear Jim, Matt, and Listees:
>
> Jim, I enjoyed your good photo of that very unusual Sikhote, thanks, and
> was interested in Matt's explanation.
>
> Nice coincidence, as when you posted that I was about to photograph an
> usual Sikhote-Alin of my own.
>
> When I started collecting Sikhotes seven or eight years ago, I was under
> the impression that all individuals had come through the atmosphere on
> their own, and all shrapnel pieces were the result of explosive
> fragmentation around the craters (this view supported, I believe, by the
> fact that only shrapnel is found in the craters?). Over time, I've seen a
> few pieces that exhibit characteristics of both individuals *and*
> shrapnel, and I'm sure some of you have too. An example would be, say, a
> ~1kg otherwise completely regmaglypted individual that has one sheared,
> shrapnel-like face. I expect this is the result of a larger individual
> fragmenting in the air shortly before impact.
>
> Now I've come across something really interesting: it appears to be a
> normal shrapnel fragment, weight 266.4 grams, except it has a very
> distinct impact pit and splash rim. It seems to me that an impact pit
> could only have been formed during flight, meaning some "pure" shrapnel
> pieces must therefore have been created by mid-air fragmentation, not
> explosive fragmentation upon impact. Could such fragmentation be the
> result of mid-air collisions, or breaking up along planes as a result of
> atmospheric pressure?
>
> Have a look:
>
> http://www.aerolite.org/gallery/sikhote-alin-266-4.htm
>
>
> Of course, this is probably all explained in Krinov's lovely little book
> about Sikhote-Alin, but my Russian isn't up to it I'm afraid : )
>
> Any comments, theories, or explanations welcomed.
>
>
> And for those of you who -- like me -- dig impact pits, I have a lovely
> little Sikhote with TWO impact pits closing on Ebay tomorrow, and a
> gorgeous oriented regmaglypted Campo closing tonight in an hour. It's at
> 12 cents per gram now! A real bargain for someone.
>
> Here they are:
>
> http://search.ebay.com/_W0QQfgtpZ1QQfrppZ25QQsassZpsiloceras
>
>
> Best to all from Tucson,
>
> Geoff N.
>
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Received on Sun 06 Nov 2005 11:29:14 AM PST