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: <[email protected]> To: <[email protected]>; <[email protected]>; "Maurizio Eltri" <[email protected]>
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

---- [email protected] 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: <[email protected]>
>
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 <[email protected]> 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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