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

[Jim Strope]

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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