[meteorite-list] Info on Sikhote Alin's shrapnel

From: Jeff Kuyken <info_at_meteoritecentral.com>
Date: Tue, 17 Nov 2009 23:43:52 +1100
Message-ID: <E8C3A05B3BA04D0FB6DBF82ADD3928D6_at_JeffPC>

Hi Graham, Jason, Fred, Maurizio and all,

I quote from the 50's Russian Academy of Sciences Sikhote Alin Recovery
Film...

"On some individuals, some of the freshly broken edges were slightly melted.
It indicated that all meteorites were from one mass which fragmented in the
Earth's atmosphere. The largest parts formed craters on impact and broke
into thousands of pieces."

So everyone is right! ;-) It has always been said that there were two
origins for Sikhote shrapnel... both atmospheric and ground fragments. You
may even find that many (if not most) of the tree embedded fragments were
from the small pieces spraying out from the crater forming events. But
that's just speculation on my part.

For anyone who has not seen the recovery film:
http://www.meteorites.com.au/odds&ends/sikhote-alin.html

Cheers,

Jeff Kuyken
Meteorites Australia
www.meteorites.com.au
Director - I.M.C.A. Inc.
www.imca.cc



----- Original Message -----
From: <ensoramanda at ntlworld.com>
To: <meteorite-list at meteoritecentral.com>; <debfred at att.net>; "Maurizio
Eltri" <maurizio.eltri at libero.it>
Sent: Tuesday, November 17, 2009 11:09 PM
Subject: Re: [meteorite-list] Info on Sikhote Alin's shrapnel


> Hi Fred, List,
>
> How does that explain all the shrapnel found in the sides of the trees or
> holes straight through standing trees? Surely shrapnel was produced both
> on the way down and on impact?
>
> I have pieces that seem to have no sign of ablation, just lots of shear
> lines.
>
> Graham, Uk
>
> ---- debfred at att.net wrote:
>> List, I have searched many Kilos of SA shrapnel without ever finding
>> ONE without some surface melting. From what I have seen shrapnel is ALL
>> air shredding with subsequent atmospheric frictional melting.
>> Cheers, Fred Olsen
>> -------------- Original message ----------------------
>> From: <ensoramanda at ntlworld.com>
>> >
>> I did not know heat was needed at all to form shrapnel...surely it is
>> just due
>> to shearing of fragments from the dramatic collisions of fragments on
>> impact or
>> during exposive events on the way down that did not leave enough time for
>> > ablation?
>> >
>> > Graham UK
>> >
>> > ---- Maurizio Eltri <maurizio.eltri at libero.it> wrote:
>> > > Hi all,
>> > >
>> > > I ask to those who are more experienced
>> > > than me,clarification about Sikhote Alin's
>> > > splinters formation.
>> > > In my opinion there can be two ways to
>> > > justify the origin of the fragments found in
>> > > the vicinity of the largest craters,
>> > > 1) The kinetic energy released at the contact
>> > > surfaces of meteorite/ground was enough to
>> > > melt the frontlayer of the meteorite with
>> > > the subsequent violent expulsion of fragments,
>> > > fused or partially fused.
>> > > 2) Having the meteorites reached the retardation
>> > > point at only 5 km of altitude, they would arrived
>> > > at an impact with their hot surfaces, this would
>> > > facilitate the expulsion of splinters.
>> > > I apologize for my bad English.
>> > > Maurizio Eltri
>> > >
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>>
>>
>>
>>
>
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Received on Tue 17 Nov 2009 07:43:52 AM PST