[meteorite-list] Question on oriented SA shrapnel

From: mark ford <markf_at_meteoritecentral.com>
Date: Wed Aug 10 07:31:49 2005
Message-ID: <6CE3EEEFE92F4B4085B0E086B2941B313B2FEC_at_s-southern01.s-southern.com>

Martin,

Thanks for the link, very interesting, (though somewhat simplified imho).

There have been quite a few oriented (with flow lines) SA shrapnel pieces pulled out of trees etc, it will be interesting to see if anyone has any idea's as to the formation mechanism. If the 3rd and 4th detonation/fragmentations where too low, (for there to be enough flight time for flowlines to form) and the explosion on impact (the normal shrapnel forming process) was not consistent with flowline formation, then the question is, how are they formed?

I guess the flowlines on my SA shrapnel could conceivably be shock induced lines formed by the explosive energy during impact? But some of the examples ive seen pictures of, look exactly like normal flow lines.

Best,
Mark Ford



-----O
riginal Message-----
From: Martin Altmann [mailto:Altmann_at_Meteorite-Martin.de]
Sent: Wednesday, August 10, 2005 11:08 AM
To: mark ford; meteorite-list_at_meteoritecentral.com
Subject: Re: [meteorite-list] Question on oriented SA shrapnel

G?ran, Mark, Jeff, List....

here a nice vizualisation of the fragmentation processes of Sikhote.
According to this model,
the pieces of the 3th and 4th fragmentation can't have flow lines.

http://www.geocities.com/diane_va/sikhote-alin/index_E.html
(click on "The fragmentation")

Martinho.

----- Original Message -----
From: "mark ford" <markf_at_ssl.gb.com>
To: <meteorite-list_at_meteoritecentral.com>
Sent: Wednesday, August 10, 2005 11:38 AM
Subject: RE: [meteorite-list] Question on oriented SA shrapnel



Hi G?ran,

Yep, I've also got a few sikhote shrapnels with definite flow lines, so must
have been due to detonation in the air, since I can't see how flow lines can
form whist imbedding in a tree etc...

Best
Mark


-----Original Message-----
From: Jeff Kuyken [mailto:info_at_meteorites.com.au]
Sent: Wednesday, August 10, 2005 2:20 AM
To: G?ran Axelsson; meteorite-list_at_meteoritecentral.com
Subject: Re: [meteorite-list] Question on oriented SA shrapnel

G'day G?ran,

My understanding (and I could be wrong here?) was that most Sikhote-Alin
shrapnel was formed when the piece/s detonated in the air during its fall.
Mike's piece is probably a good example of showing how the forces/pressure
on that piece grew to such a point, the structure of the meteorite (coarsest
octahedrite) was no longer able to support it.

Cheers,

Jeff


----- Original Message -----
From: G?ran Axelsson
To: meteorite-list_at_meteoritecentral.com
Sent: Wednesday, August 10, 2005 9:42 AM
Subject: Re: [meteorite-list] Question on oriented SA shrapnel


I was looking through some of Michael Farmers auctions on Ebay
and one piece made me puzzled.
It was a 7 kg oriented Sikhote-Alin that had flowlines. I thought that
all the shrapnel pieces were created when larger meteorites impacted
and tore the metal apart.
But flowlines should mean that this shrapnel were created in flight.

My question is if there are shrapnel pieces created in flight?

I have a neat oriented Sikhote-Alin in my collection, complete with
flowlines, thumbprinting and even fractured surfaces and teared metal.
It isn't a shrapnel and there still are some crust on the leading edge
with finer flowlines in the crust. If a shrapnel piece would have
crust with flowlines then I would be convinced that it was created
in flight but isn't it possible that there could be similar structures
without crust created when it hits the ground?

I'm just curious as this is the first shrapnel I've heard about with
flowlines.

Regards, G?ran

Michael Farmer wrote:

> I have loaded another 53 meteorites on ebay, most starting at...


   -- snipp --

>
> 7 kilo ORIENTED Sikhote-Alin piece. $4000.00 specimen, up for one cent.
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=6551087736


  -- snip --

> Mike Farmer
>
>

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Received on Wed 10 Aug 2005 07:30:44 AM PDT